From a491f2ffec53d2f7abcfeef9046ea0f30b34c1e9 Mon Sep 17 00:00:00 2001
From: epoberezkin <epoberezkin@users.noreply.github.com>
Date: Sat, 27 Jan 2024 16:52:34 +0000
Subject: [PATCH] deploy: c4cbb49f5756e6ba00f028a13af1d0048aac47a7

---
 ar/contact/index.html         | 20 ++++++++++++++++----
 ar/invitation/index.html      | 20 ++++++++++++++++----
 bg/contact/index.html         | 20 ++++++++++++++++----
 bg/invitation/index.html      | 20 ++++++++++++++++----
 contact/index.html            | 20 ++++++++++++++++----
 cs/contact/index.html         | 20 ++++++++++++++++----
 cs/invitation/index.html      | 20 ++++++++++++++++----
 css/style.css                 |  4 ++++
 css/tailwind.css              |  9 +++++++++
 de/contact/index.html         | 20 ++++++++++++++++----
 de/invitation/index.html      | 20 ++++++++++++++++----
 en/contact/index.html         | 20 ++++++++++++++++----
 en/invitation/index.html      | 20 ++++++++++++++++----
 es/contact/index.html         | 20 ++++++++++++++++----
 es/invitation/index.html      | 20 ++++++++++++++++----
 fi/contact/index.html         | 20 ++++++++++++++++----
 fi/invitation/index.html      | 20 ++++++++++++++++----
 fr/contact/index.html         | 20 ++++++++++++++++----
 fr/invitation/index.html      | 20 ++++++++++++++++----
 he/contact/index.html         | 20 ++++++++++++++++----
 he/invitation/index.html      | 20 ++++++++++++++++----
 invitation/index.html         | 20 ++++++++++++++++----
 it/contact/index.html         | 20 ++++++++++++++++----
 it/invitation/index.html      | 20 ++++++++++++++++----
 ja/contact/index.html         | 20 ++++++++++++++++----
 ja/invitation/index.html      | 20 ++++++++++++++++----
 nl/contact/index.html         | 20 ++++++++++++++++----
 nl/invitation/index.html      | 20 ++++++++++++++++----
 pl/contact/index.html         | 20 ++++++++++++++++----
 pl/invitation/index.html      | 20 ++++++++++++++++----
 pt_BR/contact/index.html      | 20 ++++++++++++++++----
 pt_BR/invitation/index.html   | 20 ++++++++++++++++----
 ru/contact/index.html         | 20 ++++++++++++++++----
 ru/invitation/index.html      | 20 ++++++++++++++++----
 uk/contact/index.html         | 20 ++++++++++++++++----
 uk/invitation/index.html      | 20 ++++++++++++++++----
 zh_Hans/contact/index.html    | 20 ++++++++++++++++----
 zh_Hans/invitation/index.html | 20 ++++++++++++++++----
 zh_Hant/contact/index.html    | 20 ++++++++++++++++----
 zh_Hant/invitation/index.html | 20 ++++++++++++++++----
 40 files changed, 621 insertions(+), 152 deletions(-)

diff --git a/ar/contact/index.html b/ar/contact/index.html
index abd06839b..bc2b6b5f0 100644
--- a/ar/contact/index.html
+++ b/ar/contact/index.html
@@ -596,8 +596,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">امسح رمز QR من تطبيق الجوال</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -627,7 +631,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">تواصل في التطبيق</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">تواصل في التطبيق</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">افتح تطبيق Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -635,7 +643,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">اضغط على زر<span class="text-active-blue"> "اتصال"</span> في التطبيق</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -647,7 +655,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -765,6 +773,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/ar/invitation/index.html b/ar/invitation/index.html
index 1f5e13c93..d5ad4a67b 100644
--- a/ar/invitation/index.html
+++ b/ar/invitation/index.html
@@ -596,8 +596,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">امسح رمز QR من تطبيق الجوال</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -627,7 +631,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">تواصل في التطبيق</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">تواصل في التطبيق</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">افتح تطبيق Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -635,7 +643,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">اضغط على زر<span class="text-active-blue"> "اتصال"</span> في التطبيق</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -647,7 +655,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -765,6 +773,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/bg/contact/index.html b/bg/contact/index.html
index e7c277af6..6ab08f97d 100644
--- a/bg/contact/index.html
+++ b/bg/contact/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/bg/invitation/index.html b/bg/invitation/index.html
index e82dd9e1b..901d4b776 100644
--- a/bg/invitation/index.html
+++ b/bg/invitation/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/contact/index.html b/contact/index.html
index 32de8ed00..c1619428a 100644
--- a/contact/index.html
+++ b/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/cs/contact/index.html b/cs/contact/index.html
index 8de27273d..c5a443561 100644
--- a/cs/contact/index.html
+++ b/cs/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Naskenujte QR kód z mobilní aplikace</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Se připojit v aplikaci</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Se připojit v aplikaci</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Otevřete aplikaci Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Klepněte na tlačítko <span class="text-active-blue">‘připojit‘</span> v aplikaci</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/cs/invitation/index.html b/cs/invitation/index.html
index e72b748d4..f6dd6a0a9 100644
--- a/cs/invitation/index.html
+++ b/cs/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Naskenujte QR kód z mobilní aplikace</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Se připojit v aplikaci</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Se připojit v aplikaci</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Otevřete aplikaci Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Klepněte na tlačítko <span class="text-active-blue">‘připojit‘</span> v aplikaci</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/css/style.css b/css/style.css
index 986d5fe00..b9a77a59d 100644
--- a/css/style.css
+++ b/css/style.css
@@ -957,3 +957,7 @@ p a{
     top: calc(66px + 2rem);
   }
 }
+
+.d-none-if-js-disabled{
+  display: none !important;
+}
\ No newline at end of file
diff --git a/css/tailwind.css b/css/tailwind.css
index ac69371dc..34d10c476 100644
--- a/css/tailwind.css
+++ b/css/tailwind.css
@@ -728,6 +728,10 @@ video {
   margin-bottom: 0.75rem;
 }
 
+.mb-32 {
+  margin-bottom: 8rem;
+}
+
 .mb-4 {
   margin-bottom: 1rem;
 }
@@ -1751,6 +1755,11 @@ video {
   text-align: center;
 }
 
+.text-2xl {
+  font-size: 1.5rem;
+  line-height: 2rem;
+}
+
 .text-3xl {
   font-size: 1.875rem;
   line-height: 2.25rem;
diff --git a/de/contact/index.html b/de/contact/index.html
index 925806aef..ecacbb6ff 100644
--- a/de/contact/index.html
+++ b/de/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scannen Sie den QR-Code aus der mobilen Applikation</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Verbinden Sie sich in der Applikation</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Verbinden Sie sich in der Applikation</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Öffnen Sie die SimpleX Applikation</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Drücken Sie die <span class="text-active-blue">‘Verbinden’</span> Taste in der Applikation</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/de/invitation/index.html b/de/invitation/index.html
index 1b2673032..dd3a2fc87 100644
--- a/de/invitation/index.html
+++ b/de/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scannen Sie den QR-Code aus der mobilen Applikation</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Verbinden Sie sich in der Applikation</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Verbinden Sie sich in der Applikation</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Öffnen Sie die SimpleX Applikation</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Drücken Sie die <span class="text-active-blue">‘Verbinden’</span> Taste in der Applikation</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/en/contact/index.html b/en/contact/index.html
index 32de8ed00..c1619428a 100644
--- a/en/contact/index.html
+++ b/en/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/en/invitation/index.html b/en/invitation/index.html
index a0550f843..6065d8f0c 100644
--- a/en/invitation/index.html
+++ b/en/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/es/contact/index.html b/es/contact/index.html
index 198c87228..0605b76dd 100644
--- a/es/contact/index.html
+++ b/es/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Escanear el código QR desde la aplicación móvil</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Conectar en la aplicación</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Conectar en la aplicación</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Abrir la aplicación Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Pulse el botón <span class="text-active-blue">‘conectar’</span> en la aplicación</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/es/invitation/index.html b/es/invitation/index.html
index 158350f97..0e89b54c9 100644
--- a/es/invitation/index.html
+++ b/es/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Escanear el código QR desde la aplicación móvil</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Conectar en la aplicación</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Conectar en la aplicación</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Abrir la aplicación Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Pulse el botón <span class="text-active-blue">‘conectar’</span> en la aplicación</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/fi/contact/index.html b/fi/contact/index.html
index a8a3c810e..8e1b30283 100644
--- a/fi/contact/index.html
+++ b/fi/contact/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Skannaa QR-koodi mobiilisovelluksesta</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Yhdisty sovelluksessa</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Yhdisty sovelluksessa</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Avaa Simplex-sovellus</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Napauta sovelluksessa olevaa <span class="text-active-blue">‘yhdistä’</span>-painiketta</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/fi/invitation/index.html b/fi/invitation/index.html
index e8829b2f7..67a7710ad 100644
--- a/fi/invitation/index.html
+++ b/fi/invitation/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Skannaa QR-koodi mobiilisovelluksesta</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Yhdisty sovelluksessa</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Yhdisty sovelluksessa</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Avaa Simplex-sovellus</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
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-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Napauta sovelluksessa olevaa <span class="text-active-blue">‘yhdistä’</span>-painiketta</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/fr/contact/index.html b/fr/contact/index.html
index ce198cd90..b3beb22c1 100644
--- a/fr/contact/index.html
+++ b/fr/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scanner le code QR depuis l'application mobile</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Se connecter dans l'application</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Se connecter dans l'application</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Ouvrir l'application SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Appuyez sur le bouton <span class="text-active-blue">'se connecter'</span> dans l'application</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/fr/invitation/index.html b/fr/invitation/index.html
index 46be468f8..8608a30d3 100644
--- a/fr/invitation/index.html
+++ b/fr/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scanner le code QR depuis l'application mobile</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Se connecter dans l'application</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Se connecter dans l'application</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Ouvrir l'application SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Appuyez sur le bouton <span class="text-active-blue">'se connecter'</span> dans l'application</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/he/contact/index.html b/he/contact/index.html
index 1357553d0..f8d88a961 100644
--- a/he/contact/index.html
+++ b/he/contact/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">סרקו קוד QR באפליקציה לנייד</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">התחברו באפליקציה</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">התחברו באפליקציה</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">פתחו את אפליקציית Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">הקישו על הלחצן <span class="text-active-blue">'התחבר'</span> באפליקציה</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/he/invitation/index.html b/he/invitation/index.html
index 780a2856b..ae13efc7b 100644
--- a/he/invitation/index.html
+++ b/he/invitation/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">סרקו קוד QR באפליקציה לנייד</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">התחברו באפליקציה</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">התחברו באפליקציה</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">פתחו את אפליקציית Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">הקישו על הלחצן <span class="text-active-blue">'התחבר'</span> באפליקציה</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/invitation/index.html b/invitation/index.html
index a0550f843..6065d8f0c 100644
--- a/invitation/index.html
+++ b/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/it/contact/index.html b/it/contact/index.html
index 64a7bb506..e731f54c1 100644
--- a/it/contact/index.html
+++ b/it/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scansiona il codice QR dall'app mobile</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connettiti nell'app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connettiti nell'app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Apri l'app SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tocca il pulsante <span class="text-active-blue">'connetti'</span> nell'app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/it/invitation/index.html b/it/invitation/index.html
index 2be4c0ba7..86ea76bef 100644
--- a/it/invitation/index.html
+++ b/it/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scansiona il codice QR dall'app mobile</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connettiti nell'app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connettiti nell'app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Apri l'app SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tocca il pulsante <span class="text-active-blue">'connetti'</span> nell'app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/ja/contact/index.html b/ja/contact/index.html
index d0bdfbdf0..37c78fdf2 100644
--- a/ja/contact/index.html
+++ b/ja/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">モバイルアプリからQRコードをスキャン</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">アプリで接続する</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">アプリで接続する</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">SimpleXアプリを開く</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">アプリの <span class="text-active-blue">「接続」</span> ボタンをタップします</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/ja/invitation/index.html b/ja/invitation/index.html
index 08e3cd9e1..f73b69ba9 100644
--- a/ja/invitation/index.html
+++ b/ja/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">モバイルアプリからQRコードをスキャン</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">アプリで接続する</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">アプリで接続する</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">SimpleXアプリを開く</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">アプリの <span class="text-active-blue">「接続」</span> ボタンをタップします</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/nl/contact/index.html b/nl/contact/index.html
index bb174cee0..2abd41587 100644
--- a/nl/contact/index.html
+++ b/nl/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan de QR-code van de mobiele app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Maak verbinding met de app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Maak verbinding met de app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open de Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tik op de knop <span class="text-active-blue">'verbinden'</span> in de app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/nl/invitation/index.html b/nl/invitation/index.html
index 653d149a1..fa2491ea2 100644
--- a/nl/invitation/index.html
+++ b/nl/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan de QR-code van de mobiele app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Maak verbinding met de app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Maak verbinding met de app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open de Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tik op de knop <span class="text-active-blue">'verbinden'</span> in de app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/pl/contact/index.html b/pl/contact/index.html
index 822d0e35d..40bca2fe0 100644
--- a/pl/contact/index.html
+++ b/pl/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Zeskanuj kod QR z aplikacji mobilnej</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Połącz się w aplikacji</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Połącz się w aplikacji</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Otwórz aplikację Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Stuknij przycisk <span class="text-active-blue">'połącz się'</span> w aplikacji</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/pl/invitation/index.html b/pl/invitation/index.html
index d7b8d8bb9..896a7927b 100644
--- a/pl/invitation/index.html
+++ b/pl/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Zeskanuj kod QR z aplikacji mobilnej</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Połącz się w aplikacji</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Połącz się w aplikacji</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Otwórz aplikację Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Stuknij przycisk <span class="text-active-blue">'połącz się'</span> w aplikacji</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/pt_BR/contact/index.html b/pt_BR/contact/index.html
index da3a7d87e..7121f2dfe 100644
--- a/pt_BR/contact/index.html
+++ b/pt_BR/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Escanear o QR code do aplicativo</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Conectar no aplicativo</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Conectar no aplicativo</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Abra o aplicativo Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Toque no botão <span class="text-active-blue">"conectar"</span> no aplicativo</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/pt_BR/invitation/index.html b/pt_BR/invitation/index.html
index 36ec24159..c1737dad7 100644
--- a/pt_BR/invitation/index.html
+++ b/pt_BR/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Escanear o QR code do aplicativo</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Conectar no aplicativo</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Conectar no aplicativo</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Abra o aplicativo Simplex</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Toque no botão <span class="text-active-blue">"conectar"</span> no aplicativo</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/ru/contact/index.html b/ru/contact/index.html
index e774d0a0b..a2429509a 100644
--- a/ru/contact/index.html
+++ b/ru/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Отсканируйте QR-код в мобильном приложении</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Подключитесь в приложении</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Подключитесь в приложении</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Откройте приложение SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Нажмите на кнопку <span class="text-active-blue">’подключиться’</span> в приложении</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/ru/invitation/index.html b/ru/invitation/index.html
index 75b308242..eabfbd7c9 100644
--- a/ru/invitation/index.html
+++ b/ru/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Отсканируйте QR-код в мобильном приложении</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Подключитесь в приложении</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Подключитесь в приложении</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Откройте приложение SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Нажмите на кнопку <span class="text-active-blue">’подключиться’</span> в приложении</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/uk/contact/index.html b/uk/contact/index.html
index 5d804cb10..6857163f6 100644
--- a/uk/contact/index.html
+++ b/uk/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Сканувати QR-код з мобільного додатка</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Підключитися в додатку</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Підключитися в додатку</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Відкрити додаток SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Торкніться кнопки <span class="text-active-blue">‘підключити’</span> в додатку</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/uk/invitation/index.html b/uk/invitation/index.html
index db457286e..2d194f89b 100644
--- a/uk/invitation/index.html
+++ b/uk/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Сканувати QR-код з мобільного додатка</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Підключитися в додатку</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Підключитися в додатку</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Відкрити додаток SimpleX</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Торкніться кнопки <span class="text-active-blue">‘підключити’</span> в додатку</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/zh_Hans/contact/index.html b/zh_Hans/contact/index.html
index 6f8157fa2..4f48ad8b0 100644
--- a/zh_Hans/contact/index.html
+++ b/zh_Hans/contact/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">从移动应用程序扫描二维码</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">在应用程序中连接</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">在应用程序中连接</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">打开 Simplex 应用程序</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">点按应用中的 <span class="text-active-blue">“连接”</span> 按钮</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/zh_Hans/invitation/index.html b/zh_Hans/invitation/index.html
index cbd38d624..784dadf06 100644
--- a/zh_Hans/invitation/index.html
+++ b/zh_Hans/invitation/index.html
@@ -594,8 +594,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">从移动应用程序扫描二维码</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -625,7 +629,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">在应用程序中连接</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">在应用程序中连接</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">打开 Simplex 应用程序</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -633,7 +641,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">点按应用中的 <span class="text-active-blue">“连接”</span> 按钮</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -645,7 +653,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -763,6 +771,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/zh_Hant/contact/index.html b/zh_Hant/contact/index.html
index 95937f593..f8f1d3e50 100644
--- a/zh_Hant/contact/index.html
+++ b/zh_Hant/contact/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>
diff --git a/zh_Hant/invitation/index.html b/zh_Hant/invitation/index.html
index 4f089771c..67ad8ee18 100644
--- a/zh_Hant/invitation/index.html
+++ b/zh_Hant/invitation/index.html
@@ -586,8 +586,12 @@ window.addEventListener('scroll',changeHeaderBg);
                 <div class="absolute mt-[-100px]">
                     <img class="" src="/img/new/contact_page_mobile.png" alt="">
                 </div>
+                
+                <noscript class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                    <p class="text-2xl font-medium text-center max-w-[234px] mb-32">Please enable JavaScript to see the QR code.</p>
+                </noscript>
 
-                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px]">
+                <div class="z-10 flex flex-col items-center pt-[40px] ml-[-15px] d-none-if-js-disabled">
                     <p class="text-base font-medium text-center max-w-[234px]">Scan QR code from mobile app</p>
                     <canvas class="conn_req_uri_qrcode"></canvas>
                 </div>
@@ -617,7 +621,11 @@ window.addEventListener('scroll',changeHeaderBg);
             </div>
 
             <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 mb-6 relative">
-                <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Connect in app</p>
+                <p class="text-xl font-medium text-grey-black dark:text-white mb-4 d-none-if-js-disabled">Connect in app</p>
+                <noscript>
+                    <p class="text-xl font-medium text-grey-black dark:text-white mb-4">Please use the link in the mobile app</p>
+                </noscript>
+
                 <a id="mobile_conn_req_uri" class="bg-[#0053D0] text-white py-3 px-8 rounded-[34px] h-[44px] text-[16px] leading-[19px] tracking-[0.02em]">Open Simplex app</a>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -625,7 +633,7 @@ window.addEventListener('scroll',changeHeaderBg);
                 </div>
             </div>
 
-            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative">
+            <div class="flex flex-col justify-center items-center w-full max-w-[468px] h-[131px] rounded-[30px] border-[1px] border-[#A8B0B4] dark:border-white border-opacity-60 relative d-none-if-js-disabled">
                 <p class="text-xl font-medium text-grey-black dark:text-white max-w-[230px] text-center">Tap the <span class="text-active-blue">‘connect’</span> button in the app</p>
 
                 <div class="absolute bg-[#0197FF] h-[44px] w-[44px] rounded-full flex items-center justify-center top-0 left-0 translate-x-[-30%] translate-y-[-30%]">
@@ -637,7 +645,7 @@ window.addEventListener('scroll',changeHeaderBg);
 </section>
 
 
-<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px]">
+<section class="hidden md:block bg-secondary-bg-light dark:bg-secondary-bg-dark py-[20px] d-none-if-js-disabled">
     <div class="container px-5">
         <div class="text-grey-black dark:text-white">
             
@@ -755,6 +763,10 @@ window.addEventListener('scroll',changeHeaderBg);
         </div>
     </div>
 </section>
+
+<script>
+    document.querySelectorAll('.d-none-if-js-disabled').forEach(el => el.classList.remove('d-none-if-js-disabled'));
+</script>
 <div id="address-portability" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Address portability</h1><div class="overlay-content"><p>Similarly to <a href="https://en.wikipedia.org/wiki/Local_number_portability">phone number portability</a> (the ability of the customer to transfer the service to another provider without changing the number), the address portability means the ability of a communication service customer to change the service provider without changing the service address. Many <a href="#federated-network">federated networks</a> support SRV records to provide address portability, but allowing service users to set up their own domains for the addresses is not as commonly supported by the available server and client software as for email.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="federated-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Federated network</h1><div class="overlay-content"><p>Federated network is provided by several entities that agree upon the standards and operate the network collectively. This allows the users to choose their provider, that will hold their account, their messaging history and contacts, and communicate with other providers' servers on behalf of the user. The examples are email, XMPP, Matrix and Mastodon.</p><p>The advantage of that design is that there is no single organization that all users depend on, and the standards are more difficult to change, unless it benefits all users. There are several disadvantages: 1) the innovation is slower, 2) each user account still depends on a single organization, and in most cases can't move to another provider without changing their network address – there is no <a href="#address-portability">address portability</a>, 3) the security and privacy are inevitably worse than with the centralized networks.</p><p><a href="https://en.wikipedia.org/wiki/Federation_(information_technology)">Federation on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="anonymous-credentials" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Anonymous credentials</h1><div class="overlay-content"><p>The credential that allows proving something, e.g. the right to access some resource, without identifying the user. This credential can either be generated by a trusted party or by the user themselves and provided together with the request to create the resource. The first approach creates some centralized dependency in most cases. The second approach does not require any trust - this is used in SimpleX network to authorize access to the messaging queues.</p><p><a href="https://en.wikipedia.org/wiki/Digital_credential">Digital credential on Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="blockchain" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Blockchain</h1><div class="overlay-content"><p>In a wide sense, blockchain means a sequence of blocks of data, where each block contains a cryptographic hash of the previous block, thus providing integrity to the whole chain. Blockchains are used in many communication and information storage systems to provide integrity and immutability of the data. For example, BluRay disks use blockchain. SimpleX messaging queues also use blockchain - each message includes the hash of the previous message, to ensure the integrity – if any message is modified it will be detected by the recipient when the next message is received. Blockchains are a subset of <a href="#merkle-directed-acyclic-graph">Merkle directed acyclic graphs</a>.</p><p>In a more narrow sense, particularly in media, blockchain is used to refer specifically to distributed ledger, where each record also includes the hash of the previous record, but the blocks have to be agreed by the participating peers using some <a href="https://en.wikipedia.org/wiki/Consensus_(computer_science)">consensus protocol</a>.</p><p><a href="https://en.wikipedia.org/wiki/Blockchain">Wikipedia</a></p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="merkle-directed-acyclic-graph" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Merkle directed acyclic graph</h1><div class="overlay-content"><p>Also known as Merkle DAG, a data structure based on a general graph structure where node contains the cryptographic hashes of the previous nodes that point to it. Merkle trees are a subset of Merkle DAGs - in this case each leaf contains a cryptographic hash of the parent.</p><p>This structure by design allows to verify the integrity of the whole structure by computing its hashes and comparing with the hashes included in the nodes, in the same way as with <a href="#blockchain">blockchain</a>.</p><p>The motivation to use DAG in distributed environments instead of a simpler linear blockchain is to allow concurrent additions, when there is no requirement for a single order of added items. Merkle DAG is used, for example, in <a href="https://en.wikipedia.org/wiki/InterPlanetary_File_System">IPFS</a> and will be used in decentralized SimpleX groups.</p><p><a href="https://en.wikipedia.org/wiki/Merkle_tree">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="break-in-recovery" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Break-in recovery</h1><div class="overlay-content"><p>Also known as break-in recovery, it is the quality of the end-to-end encryption scheme allowing to recover security against a passive attacker who observes encrypted messages after compromising one (or both) of the parties. Also known as recovery from compromise or break-in recovery. <a href="#double-ratchet-algorithm">Double-ratchet algorithm</a> has this quality.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="double-ratchet-algorithm" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Double ratchet algorithm</h1><div class="overlay-content"><p>It is used by two parties to exchange <a href="#end-to-end-encryption">end-to-end encrypted</a> messages. The parties will use some <a href="#key-agreement-protocol">key agreement protocol</a> to agree on the initial shared secret key.</p><p>Double Ratchet algorithm provides <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>. It is <a href="https://signal.org/docs/specifications/doubleratchet">designed by Signal</a>, and used in SimpleX Chat and many other secure messengers. Most experts consider it the state-of-the-art encryption protocol in message encryption.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="centralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Centralized network</h1><div class="overlay-content"><p>Centralized networks are provided or controlled by a single entity. The examples are Threema, Signal, WhatsApp and Telegram. The advantage of that design is that the provider can innovate faster, and has a centralized approach to security. But the disadvantage is that the provider can change or discontinue the service, and leak, sell or disclose in some other way all users' data, including who they are connected with.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="content-padding" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Content padding</h1><div class="overlay-content"><p>Also known as content padding, it is the process of adding data to the beginning or the end of a message prior to encryption. Padding conceals the actual message size from any eavesdroppers. SimpleX has several encryption layers, and prior to each encryption the content is padded to a fixed size.</p><p><a href="https://en.wikipedia.org/wiki/Padding_(cryptography)">Wikipedia</a>.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="decentralized-network" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Decentralized network</h1><div class="overlay-content"><p>Decentralized network is often used to mean "the network based on decentralized blockchain". In its original meaning, decentralized network means that there is no central authority or any other point of centralization in the network, other than network protocols specification. The advantage of decentralized networks is that they are resilient to censorship and to the provider going out of business. The disadvantage is that they are often slower to innovate, and the security may be worse than with the centralized network.</p><p>The examples of decentralized networks are email, web, DNS, XMPP, Matrix, BitTorrent, etc. All these examples have a shared global application-level address space. Cryptocurrency blockchains not only have a shared address space, but also a shared state, so they are more centralized than email. Tor network also has a shared global address space, but also a central authority. SimpleX network does not have a shared application-level address space (it relies on the shared transport-level addresses - SMP relay hostnames or IP addresses), and it does not have any central authority or any shared state.</p></div><svg class="close-overlay-btn" id="cross" width="16" height="16" viewBox="0 0 13 13" xmlns="http://www.w3.org/2000/svg"><path d="M12.7973 11.5525L7.59762 6.49833L12.7947 1.44675C13.055 1.19371 13.0658 0.771991 12.8188 0.505331C12.5718 0.238674 12.1602 0.227644 11.8999 0.480681L6.65343 5.58028L1.09979 0.182228C0.805 0.002228 0.430001 0.002228 0.135211 0.182228C-0.159579 0.362228 -0.159579 0.697228 0.135211 0.877228L5.68885 6.27528L0.4918 11.3295C0.231501 11.5825 0.220703 12.0042 0.467664 12.2709C0.714625 12.5376 1.12625 12.5486 1.38655 12.2956L6.63302 7.196L12.1867 12.5941C12.4815 12.7741 12.8565 12.7741 13.1513 12.5941C13.4461 12.4141 13.4461 12.0791 13.1513 11.8991L12.7973 11.5525Z"></path></svg></div></div><div id="defense-in-depth" class="overlay glossary-overlay hidden"><div class="overlay-card"><h1 class="overlay-title">Defense in depth</h1><div class="overlay-content"><p>Originally, it is a military strategy that seeks to delay rather than prevent the advance of an attacker, buying time and causing additional casualties by yielding space.</p><p>In information security, defense in depth represents the use of multiple computer security techniques to help mitigate the risk of one component of the defense being compromised or circumvented. An example could be anti-virus software installed on individual workstations when there is already virus protection on the firewalls and servers within the same environment.</p><p>SimpleX network applies defense in depth approach to security by having multiple layers for the communication security and privacy:</p><ul>
 <li>double ratchet algorithm for <a href="#end-to-end-encryption">end-to-end encryption</a> with <a href="#forward-secrecy">perfect forward secrecy</a> and <a href="#post-compromise-security">post-compromise security</a>,</li>
 <li>additional layer of end-to-end encryption for each messaging queue and another encryption layer of encryption from the server to the recipient inside TLS to prevent correlation by ciphertext,</li>