discourse/app/views/user_notifications/digest.html.erb

<div class="summary-email">

<span class="preheader" style="display:none!important;color:#f3f3f3;font-size:1px;line-height:1px;max-height:0;max-width:0;mso-hide:all!important;opacity:0;overflow:hidden;visibility:hidden">
  <%= @preheader_text %>
</span>

<%- if I18n.t('user_notifications.digest.custom.html.header').present? %>
  <table class="digest-header logo-header" dir="<%= rtl? ? 'rtl' : 'ltr' %>" style="width:100%;border-spacing:0;padding:0;">
    <tr>
      <td style="padding:0;">
        <%= raw(t 'user_notifications.digest.custom.html.header') %>
      </td>
    </tr>
  </table>
<%- else %>
<table class="digest-header text-header with-dir" style="background-color:#<%= @header_bgcolor -%>;width:100%;">
  <tr>
    <td align="center" style="text-align: center;padding: 20px 0; font-family:Arial,sans-serif;">

  <a href="<%= Discourse.base_url %>" style="color:#<%= @header_color -%>;font-size:22px;text-decoration:none;">
  <%- if logo_url.blank? %>
    <%= SiteSetting.title %>
  <%- else %>
    <img src="<%= logo_url %>" height="40" style="clear:both;display:block;height:40px;margin:auto;max-width:100%;outline:0;text-decoration:none;" alt="<%= SiteSetting.title %>">
  <%- end %>
  </a>

    </td>
  </tr>
</table>
<%- end %>

<table class="body digest-content with-dir" style="width:100%;background:#f3f3f3;padding:0;border-spacing:0;font-family:Arial,sans-serif;font-size:14px;font-weight:200;line-height:1.3;vertical-align:top;">
  <tr>
    <td class="side-spacer" style="width:5%;vertical-align:top;padding:0;">
      <div class="with-accent-colors">
        <table class="spacer with-accent-colors" style="border-spacing:0;padding:0;width:100%">
          <tbody>
            <tr>
              <td height="400px" style="height:400px;border-collapse:collapse!important;margin:0;mso-line-height-rule:exactly;padding:0;">&nbsp;</td>
            </tr>
          </tbody>
        </table>
      </div>
    </td>
    <td style="vertical-align:top;padding:0;font-family:Arial,sans-serif;">
      <table align="center" class="digest-content-header with-accent-colors with-dir" style="border-spacing:0;margin:0;padding:0;vertical-align:top;width:100%">
        <tbody>
          <tr>
            <td style="border-collapse:collapse!important;color:#0a0a0a;line-height:1.3;margin:0;padding:0;vertical-align:top;word-wrap:normal">

<br/>
<center class="header-since-last-visit with-accent-colors" style="font-size:22px;font-weight:400;mso-line-height-rule:exactly;line-height:36px;"><%=t 'user_notifications.digest.since_last_visit' %></center>



<table class="header-stats with-dir" style="table-layout:fixed;margin:10px 0 20px 0;padding:0;vertical-align:top;width:100%">
<tbody>
  <tr class="header-stat-count">
    <%- @counts.each do |count| -%>
      <td style="text-align:center;font-size:36px;font-weight:400;">
        <a class="with-accent-colors" href="<%= count[:href] -%>"><strong><%= count[:value] -%></strong></a>
      </td>
    <%- end -%>
  </tr>
  <tr class="header-stat-description">
    <%- @counts.each do |count| -%>
      <td style="font-size:14px;font-weight:400;text-align:center;">
        <a class="with-accent-colors" href="<%= count[:href] -%>"><strong><%=t count[:label_key] -%></strong></a>
      </td>
    <%- end -%>
  </tr>
</tbody>
</table>

<center class="header-popular-topics with-accent-colors" style="font-size:22px;font-weight:400;margin-bottom: 8px; mso-line-height-rule:exactly;line-height:36px;"><%=t 'user_notifications.digest.popular_topics' %></center>


            </td>
          </tr>
        </tbody>
      </table>
      <table class="with-dir" align="center" style="border-spacing:0;background:#fefefe;margin:0;padding:0;text-align:center;vertical-align:top;width:100%">
        <tbody>
          <tr>
            <td class="digest-popular-topic-wrapper with-dir" style="-moz-hyphens:auto;-webkit-hyphens:auto;border-collapse:collapse!important;color:#0a0a0a;hyphens:auto;line-height:1.3;margin:0;padding:0;vertical-align:top;word-wrap:normal">

<% @popular_topics.each_with_index do |t, i| %>
<!--   Beginning of Popular Topic   -->
<table class="digest-topic popular-topic with-dir" style="width:100%">
  <tbody>
    <tr>
      <td class="digest-topic-category with-dir" style="margin:0;padding:<%= rtl? ? '0 16px 0 0' : '0 0 0 16px' %>;vertical-align:top;">
        <p style="color:#8f8f8f;line-height:1.3;margin: 20px 0 0 0;">
          <%= category_badge(t.category, inline_style: true, absolute_url: true) %>
        </p>
      </td>
      <td class="with-dir" style="margin:0;padding:<%= rtl? ? '0 0 0 16px' : '0 16px 0 0' %>;text-align:<%= rtl? ? 'left' : 'right' %>;vertical-align:top;">
        <p class="text-right digest-created-at" style="color:#8f8f8f;line-height:1.3;margin:20px 0 0 0;font-weight:400;">
          <%= short_date(t.created_at) %>
        </p>
      </td>
    </tr>
  </tbody>
</table>

<table class="with-dir" style="vertical-align:top;width:100%">
  <tbody>
    <tr>
      <td class="with-dir" style="padding:<%= rtl? ? '0 16px 8px 8px' : '0 8px 8px 16px' %>;width:100%;">
        <h2 class="digest-topic-title" style="font-size:18px;font-weight:400;line-height:1.3;margin:0;padding:0;word-wrap:normal">
          <a href="<%= Discourse.base_url_no_prefix + t.relative_url %>" style="font-weight:400;line-height:1.3;margin:0;padding:0;text-decoration:none">
            <strong><%= gsub_emoji_to_unicode(t.title.truncate(100, separator: /\s/)) -%></strong>
          </a>
        </h2>
        <%- if SiteSetting.show_topic_featured_link_in_digest && t.featured_link %>
          <a class='topic-featured-link' href='<%= t.featured_link %>'><%= raw topic_featured_link_domain(t.featured_link) %></a>
        <%- end %>
      </td>
    </tr>
  </tbody>
</table>

<table class="with-dir" style="padding:0;position:relative;vertical-align:top;width:100%">
  <tbody>
    <tr>
      <td class="digest-topic-op" style="color:#0a0a0a;line-height:1.3;margin:0 auto;padding:<%= rtl? ? '0 16px 0 0' : '0 0 0 16px' %>;width:50px;vertical-align:top;">
        <img src="<%= t.user.small_avatar_url -%>" style="border-radius:50%;clear:both;display:block;float:none;height:50px;width:50px;margin:0;max-width:100%;outline:0;text-align:center;text-decoration:none;" align="center" alt="<%= t.user.username -%>">
      </td>
      <td style="color:#0a0a0a;padding:<%= rtl? ? '0 8px 0 16px' : '0 16px 0 8px' %>;vertical-align:top;">
        <% if t.user %>
          <% if SiteSetting.enable_names? && t.user.name.present? && t.user.name.downcase != t.user.username.downcase %>
            <h6 class="digest-topic-username" style="color:inherit;line-height:1.3;margin:0;padding:0;font-weight: normal;font-size:16px;"><%= t.user.name -%></h6>
          <% end %>
          <p class="digest-topic-name" style="color:inherit;font-size:14px;font-weight:400;line-height:1.3;margin:0 0 8px 0;padding:0;word-wrap:normal;"><%= t.user.username -%></p>
        <% end %>
      </td>
      <%- if show_image_with_url(t.image_url) && t.featured_link.nil? && !(@excerpts[t.first_post&.id]||"").include?(t.image_url) -%>
        <td style="margin:0;padding:<%= rtl? ? '0 8px 0 16px' : '0 16px 0 8px' %>;vertical-align:top;" align="right">
          <img src="<%= url_for_email(t.image_url) -%>" height="64" style="margin:auto;max-height:64px;max-width:100%;outline:0;text-decoration:none;" alt="topic image">
        </td>
      <%- end -%>
    </tr>
  </tbody>
</table>

<%- if t.first_post.present? && !t.first_post.user_deleted %>
<table class="digest-topic-body with-dir" style="border-bottom:1px solid #f3f3f3;mso-border-bottom-alt:none;padding:0;vertical-align:top;width:100%;">
  <tbody>
    <tr>
      <td class="post-excerpt" style="color:#0a0a0a;font-size:14px;padding:0 16px 0 16px;width:100%;font-weight:normal;mso-padding-alt: 16px;">
        <%= @excerpts[t.first_post.id] %>
      </td>
    </tr>
  </tbody>
</table>
<%- end %>

<table class="digest-topic-stats with-dir" style="padding:0;vertical-align:top;width:100%; margin-top:20px;">
  <tbody>
    <tr>
      <td class="digest-topic-stat" style="padding:<%= rtl? ? '0 16px 16px 8px' : '0 8px 16px 16px' %>;white-space:nowrap;vertical-align:top;width:75px">
        <img class="digest-icon" src="<%= email_image_url 'heart.png' -%>" style="clear:both;display:inline-block;float:<%= rtl? ? 'right' : 'left' %>;height:20px;margin:0;max-width:100%;opacity:.4;outline:0;text-decoration:none;width:auto" alt="likes">
        <span style="color:#8f8f8f;float:<%= rtl? ? 'right' : 'left' %>;line-height:1.3;margin:0 5px 10px 5px;padding:0;font-weight:400;">&nbsp;<%= t.like_count -%></span>
      </td>
      <td class="digest-topic-stat" style="padding:0 8px 16px 8px;white-space:nowrap;vertical-align:top;width:75px">
        <img class="digest-icon" src="<%= email_image_url 'comment.png' -%>" style="clear:none;display:inline-block;float:<%= rtl? ? 'right' : 'left' %>;height:20px;margin:0;max-width:100%;opacity:.4;outline:0;text-decoration:none;width:auto" alt="replies">
        <span style="color:#8f8f8f;float:<%= rtl? ? 'right' : 'left' %>;line-height:1.3;margin:0 5px 10px 5px;padding:0;font-weight:400;">&nbsp;<%= t.posts_count - 1 -%></span>
      </td>
      <td class="digest-topic-posters" style="padding:0 8px 16px 8px;white-space:nowrap;vertical-align:top;">
        <% t.posters_summary.each do |ps| %>
          <% if ps.user %>
            <img src="<%= ps.user.small_avatar_url -%>" style="border-radius:50%;clear:both;display:inline-block;height:20px;width:20px;outline:0;text-decoration:none;" height="20" width="20" alt="<%= ps.user.username -%>">
          <% end %>
        <% end %>
      </td>
      <td class="digest-read-more-wrap" style="line-height:1.3;padding:<%= rtl? ? '0 8px 0 16px' : '0 16px 0 8px' %>;text-align:<%= rtl? ? 'left' : 'right' %>;white-space:nowrap;vertical-align:top;">
        <span class="with_accent-colors mso-accent-link">
          <a href="<%= Discourse.base_url_no_prefix + t.relative_url %>" class="digest-button with-accent-colors" style="width:100%;text-decoration:none;padding:8px 16px;white-space:nowrap;">
            <%=t 'user_notifications.digest.join_the_discussion' %>
          </a>
        </span>
      </td>
    </tr>
  </tbody>
</table>
<div style="background-color:#f3f3f3;">
  <table class="spacer with-dir" style="padding:0;width:100%;background-color:#f3f3f3">
    <tbody><tr><td height="20px" style="border-collapse:collapse!important;line-height:20px;margin:0;mso-line-height-rule:exactly;padding:0;">&#xA0;</td></tr></tbody>
  </table>
</div>
<!--   End of Popular Topic   -->

<% if i < 5 %>
<%= digest_custom_html("below_post_#{i+1}") %>
<% end %>

<% end %>

            </td>
          </tr>
        </tbody>
      </table>
    </td>
    <td class="side-spacer" style="width:5%;vertical-align:top;padding:0;">
      <!-- Background that goes down part-way behind content -->
      <div class="with-accent-colors">
        <table class="spacer with-dir with-accent-colors" style="border-spacing:0;padding:0;width:100%">
          <tbody>
            <tr>
              <td height="400px" style="height:400px;border-collapse:collapse!important;margin:0;mso-line-height-rule:exactly;padding:0;">&nbsp;</td>
            </tr>
          </tbody>
        </table>
      </div>
    </td>
  </tr>
</table>

<% if @popular_posts.present? %>

<center class="header-popular-posts" style="color:#0a0a0a;background:#f3f3f3;font-size:22px;font-weight:400;padding: 20px 0;font-family:Arial,sans-serif;">
  <%=t 'user_notifications.digest.popular_posts' %>
</center>

<table class="body with-dir" style="width:100%;background:#f3f3f3;border-spacing:0;border-collapse:collapse!important;font-family:Arial,sans-serif;font-size:14px;font-weight:200;line-height:1.3;padding:0;vertical-align:top;">
  <tr>
    <td class="side-spacer" style="width:5%;padding:0;">&nbsp;</td>
    <td class="with-dir" align="center" valign="top" style="width:90%;border-collapse:collapse!important;line-height:1.3;margin:0;padding:0;vertical-align:top;">

<% @popular_posts.each do |post| %>

<!--   Beginning of Popular Post   -->
<table class="popular-post-excerpt with-dir" style="width:100%;background:#fefefe;border-spacing:0;padding:0;vertical-align:top;">
  <tbody>
    <tr>
      <td class="post-excerpt with-dir" style="color:#0a0a0a;font-size:14px;font-weight:normal;padding:16px;width:100%;">
        <%= email_excerpt(post.cooked, post) %>
      </td>
    </tr>
  </tbody>
</table>

<table class="popular-post-spacer with-dir" style="border-spacing:0;background-color:#f3f3f3;padding:0;vertical-align:top;width:100%">
  <tbody>
    <tr>
      <td style="border-spacing:0;padding:0;color:#0a0a0a;line-height:1.3;padding:<%= rtl? ? '0 65px 0 0' : '0 0 0 65px' %>;">
        <img src="<%= email_image_url 'right_triangle.png' -%>" style="clear:both;display:block;height:20px;width:20px;outline:0;text-decoration:none;" alt="">
      </td>
    </tr>
  </tbody>
</table>

<table class="popular-post-meta with-dir" style="background-color:#f3f3f3;padding:0;position:relative;vertical-align:top;width:100%">
  <tbody>
    <tr>
      <td style="padding:0 8px 8px 8px;width:50px;vertical-align:top;">
        <img src="<%= post.user.small_avatar_url -%>" style="border-radius:50%;clear:both;display:block;height:50px;width:50px;outline:0;" alt="<%= post.user.username -%>">
      </td>
      <td style="color:#0a0a0a;line-height:1.3;padding:0 8px 8px 8px;vertical-align:top;">
        <% if post.user %>
          <% if SiteSetting.enable_names? && post.user.name && post.user.name.downcase != post.user.username.downcase %>
            <h6 style="color:inherit;line-height:1.3;margin:0;padding:0;font-weight: normal;font-size:16px;"><%= post.user.name -%></h6>
          <% end %>
          <p style="color:inherit;font-size:14px;font-weight:400;line-height:1.3;margin:0 0 8px 0;padding:0;word-wrap:normal;"><%= post.user.username -%></p>
        <% end %>
      </td>
      <td style="color:#0a0a0a;line-height:1.3;padding:0 8px 8px 8px;text-align:<%= rtl? ? 'left' : 'right' %>;">
        <p style="color:#8f8f8f;line-height:1.3;margin:0 0 10px 0;padding:0;">
          <a href="<%= post.full_url -%>" style="font-weight:400;line-height:1.3;margin:0;padding:0;text-decoration:none"><%= gsub_emoji_to_unicode(post.topic.title.truncate(100, separator: /\s/)) -%></a>
        </p>
        <a href="<%= post.full_url -%>" class="digest-button with-accent-colors" style="width:100%;text-decoration:none;padding:8px 16px;white-space: nowrap;">
          <%=t 'user_notifications.digest.join_the_discussion' %>
        </a>
      </td>
    </tr>
  </tbody>
</table>

<div style="background-color:#f3f3f3">
  <table class="spacer with-dir" style="padding:0;vertical-align:top;width:100%;background-color:#f3f3f3">
    <tbody><tr><td height="40" style="-moz-hyphens:auto;-webkit-hyphens:auto;border-collapse:collapse!important;color:#0a0a0a;font-size:40px;font-weight:400;hyphens:auto;line-height:40px;margin:0;mso-line-height-rule:exactly;padding:0;vertical-align:top;word-wrap:normal">&#xA0;</td></tr></tbody>
  </table>
</div>
<!--   End of Popular Post   -->

<% end %>

    </td>
    <td class="side-spacer" style="width:5%;padding:0;">&nbsp;</td>
  </tr>
</table>

<% end %>


<%= digest_custom_html("above_popular_topics") %>

<% if @other_new_for_you.present? %>
<center class="digest-new-header" style="color:#0a0a0a;background:#f3f3f3;font-size:22px;font-weight:400;padding-bottom: 8px;font-family:Arial,sans-serif;mso-line-height-rule:exactly;line-height:36px;"><%=t 'user_notifications.digest.more_new' %></center>

<table class="digest-new-topics body with-dir" style="width:100%;background:#f3f3f3;border-spacing:0;border-collapse:collapse!important;font-family:Arial,sans-serif;font-size:14px;font-weight:200;line-height:1.3;padding:0;vertical-align:top;">
  <tr>
    <td class="side-spacer" style="width:5%;padding:0;">&nbsp;</td>
    <td align="center" valign="top" style="width:90%;border-collapse:collapse!important;margin:0;padding:0;">

<table class="digest-new-topic with-dir" style="padding:0;vertical-align:top;width:100%">
  <tbody>

<% @other_new_for_you.each do |t| %>

<!--   Begin new topic  -->
    <tr style="vertical-align:top;">
      <td class="digest-new-topic-title with-dir" style="padding:8px;">
        <a href="<%= Discourse.base_url_no_prefix + t.relative_url %>" style="font-weight:400;line-height:1.3;margin:0;padding:0;text-decoration:none;">
          <strong><%= gsub_emoji_to_unicode(t.title.truncate(100, separator: /\s/)) -%></strong>
        </a>
        <%- if SiteSetting.show_topic_featured_link_in_digest && t.featured_link %>
          <a class='topic-featured-link' href='<%= t.featured_link %>'><%= raw topic_featured_link_domain(t.featured_link) %></a>
        <%- end %>
        <p class="digest-new-topic-category" style="color:#0a0a0a;line-height:1.3;margin:0 0 10px 0;padding:0;">
          <%= category_badge(t.category, inline_style: true, absolute_url: true) %>
        </p>
      </td>
      <td class="digest-new-topic-posters with-dir" style="padding:8px;">
        <% t.posters_summary[0,2].each do |ps| %>
          <% if ps.user %>
            <img src="<%= ps.user.small_avatar_url -%>" style="height:20px;width:20px;margin:<%= rtl? ? '0 0 5px 5px' : '0 5px 5px 0' %>;border-radius:50%;clear:both;display:inline-block;outline:0;text-decoration:none;" alt="<%= ps.user.username -%>">
          <% end %>
        <% end %>
      </td>
      <td class="digest-new-topic-stat with-dir" style="padding:8px;">
        <img class="digest-icon" src="<%= email_image_url 'heart.png' -%>" style="clear:both;display:inline-block;float:<%= rtl? ? 'right' : 'left' %>;height:20px;margin:0;max-width:100%;opacity:.4;outline:0;text-decoration:none;width:auto" alt="likes">
        <p style="color:#8f8f8f;float:<%= rtl? ? 'right' : 'left' %>;line-height:1.3;margin:0 5px 10px 5px;padding:0;font-weight:400;"><%= t.like_count -%></p>
      </td>
      <td class="digest-new-topic-stat digest-replies with-dir" style="padding:8px;">
        <img class="digest-icon" src="<%= email_image_url 'comment.png' -%>" style="clear:none;display:inline-block;float:<%= rtl? ? 'right' : 'left' %>;height:20px;margin:0;max-width:100%;opacity:.4;outline:0;text-decoration:none;width:auto" alt="replies">
        <p style="color:#8f8f8f;float:<%= rtl? ? 'right' : 'left' %>;line-height:1.3;margin:0 5px 10px 5px;padding:0;font-weight:400;"><%= t.posts_count - 1 -%></p>
      </td>
    </tr>

    <tr class="digest-new-topic-spacer"><td colspan="6" height="10px" style="border-collapse:collapse!important;line-height:10px;margin:0;mso-line-height-rule:exactly;padding:0;">&#xA0;</td></tr>

<!--   End new topic  -->

<% end %>

</tbody>
</table>

    </td>
    <td class="side-spacer" style="width:5%;padding:0;">&nbsp;</td>
  </tr>
</table>

<% end %>

<%= digest_custom_html("below_popular_topics") %>


    </td>
    <td class="side-spacer" style="width:5%;padding:0;">&nbsp;</td>
  </tr>
</table>
<style>
  @media only screen {
    html {
      min-height: 100%;
      background: #f3f3f3
    }
  }

  @media only screen and (max-width:900px) {
    table.body img {
      width: auto;
      height: auto
    }
    table.body center {
      min-width: 0!important;
    }
    table.body .side-spacer {
      width: 2.5%!important;
    }
    table.body .column,
    table.body .columns {
      height: auto!important;
      -moz-box-sizing: border-box;
      -webkit-box-sizing: border-box;
      box-sizing: border-box;
      padding-left: 16px!important;
      padding-right: 16px!important
    }
    table.body .column .column,
    table.body .column .columns,
    table.body .columns .column,
    table.body .columns .columns {
      padding-left: 0!important;
      padding-right: 0!important
    }
  }
</style>


<%= digest_custom_html("above_footer") %>

<table class='summary-footer with-dir' style="width: 100%">
  <tr>
    <td align="center">
  <%=raw(t 'user_notifications.digest.unsubscribe',
           site_link: html_site_link,
           email_preferences_link: link_to(t('user_notifications.digest.your_email_settings'), Discourse.base_url + '/my/preferences/emails'),
           unsubscribe_link: link_to(t('user_notifications.digest.click_here'), "#{Discourse.base_url}/email/unsubscribe/#{@unsubscribe_key}"))  %>
    </td>
  </tr>
</table>

<%= digest_custom_html("below_footer") %>

</div>