diff --git a/backend/api/schemas/site.ts b/backend/api/schemas/site.ts
index c873aad6..6ced3e3e 100644
--- a/backend/api/schemas/site.ts
+++ b/backend/api/schemas/site.ts
@@ -34,6 +34,24 @@ export async function registerSchemas(app: FastifyInstance): Promise<void> {
       footerExtra: {
         type: 'string'
       },
+      banner: {
+        type: 'object',
+        description:
+          'A notice shown above the contents of every page of this site, styled as a caution admonition. The content is markdown, and is rendered by the app rather than stored as HTML.',
+        properties: {
+          isEnabled: {
+            type: 'boolean'
+          },
+          title: {
+            type: 'string',
+            maxLength: 255
+          },
+          content: {
+            type: 'string',
+            maxLength: 8192
+          }
+        }
+      },
       pageExtensions: {
         type: 'array',
         items: {
diff --git a/backend/api/sites.ts b/backend/api/sites.ts
index 4e50afa3..6bb02c29 100644
--- a/backend/api/sites.ts
+++ b/backend/api/sites.ts
@@ -18,6 +18,7 @@ const SITE_CONFIG_KEYS = [
   'company',
   'contentLicense',
   'footerExtra',
+  'banner',
   'pageExtensions',
   'logoText',
   'sitemap',
@@ -262,6 +263,7 @@ async function routes(app: FastifyInstance) {
       company?: string
       contentLicense?: string
       footerExtra?: string
+      banner?: { isEnabled?: boolean; title?: string; content?: string }
       pageExtensions?: string[]
       logoText?: boolean
       sitemap?: boolean
@@ -329,6 +331,9 @@ async function routes(app: FastifyInstance) {
             footerExtra: {
               type: 'string'
             },
+            banner: {
+              $ref: 'Site#/properties/banner'
+            },
             pageExtensions: {
               type: 'array',
               items: {
diff --git a/backend/locales/en.json b/backend/locales/en.json
index 6532f453..ce9084ce 100644
--- a/backend/locales/en.json
+++ b/backend/locales/en.json
@@ -297,6 +297,13 @@
   "admin.general.allowRatingsHint": "Can users leave ratings on pages? Can be restricted using Page Rules.",
   "admin.general.allowSearch": "Allow Search",
   "admin.general.allowSearchHint": "Can users search for content they have read access to?",
+  "admin.general.banner": "Site-wide Banner",
+  "admin.general.bannerContent": "Banner Contents",
+  "admin.general.bannerContentHint": "The text of the banner. Basic markdown is supported.",
+  "admin.general.bannerEnabled": "Show Banner",
+  "admin.general.bannerEnabledHint": "Display a notice at the top of every page of this site.",
+  "admin.general.bannerTitle": "Banner Title",
+  "admin.general.bannerTitleHint": "Heading shown above the banner contents. Leave empty to hide.",
   "admin.general.companyName": "Company / Organization Name",
   "admin.general.companyNameHint": "Name to use when displaying copyright notice in the footer. Leave empty to hide.",
   "admin.general.contentLicense": "Content License",
diff --git a/backend/models/sites.ts b/backend/models/sites.ts
index 7266e504..589d20b4 100644
--- a/backend/models/sites.ts
+++ b/backend/models/sites.ts
@@ -99,6 +99,11 @@ class Sites {
             company: '',
             contentLicense: '',
             footerExtra: '',
+            banner: {
+              isEnabled: false,
+              title: '',
+              content: ''
+            },
             pageExtensions: ['md', 'html', 'txt'],
             discoverable: false,
             defaults: {
@@ -351,6 +356,11 @@ class Sites {
         company: '',
         contentLicense: '',
         footerExtra: '',
+        banner: {
+          isEnabled: false,
+          title: '',
+          content: ''
+        },
         pageExtensions: ['md', 'html', 'txt'],
         discoverable: false,
         defaults: {
diff --git a/frontend/src/components/BlockPickerOverlay.vue b/frontend/src/components/BlockPickerOverlay.vue
index 20108928..e897ad2a 100644
--- a/frontend/src/components/BlockPickerOverlay.vue
+++ b/frontend/src/components/BlockPickerOverlay.vue
@@ -128,6 +128,9 @@ import { useSiteStore } from '@/stores/site'
  * `<block-name prop="value">` — the element the component registers itself as.
  */
 
+/** Blocks the editor's side toolbar inserts directly, so the picker leaves them out. */
+const TOOLBAR_BLOCKS = ['tabs']
+
 // STORES
 
 const siteStore = useSiteStore()
@@ -148,8 +151,16 @@ const state = reactive({
 
 // COMPUTED
 
-/** Only blocks this site has switched on: the rest cannot render, so offering them is a trap. */
-const blocks = computed(() => state.blocks.filter((block) => block.isEnabled))
+/**
+ * Blocks offered here: the ones this site has switched on, minus the ones the editor inserts itself.
+ *
+ * A block that is off cannot render, so offering it is a trap. Tabs is on but has its own button in
+ * the editor's side toolbar, which inserts the very same markup — listing it here as well is a second
+ * way to the same place.
+ */
+const blocks = computed(() =>
+  state.blocks.filter((block) => block.isEnabled && !TOOLBAR_BLOCKS.includes(block.block))
+)
 
 const markdown = computed(() => (state.selected ? blockMarkdown(state.selected, state.values) : ''))
 
diff --git a/frontend/src/components/SiteBanner.vue b/frontend/src/components/SiteBanner.vue
new file mode 100644
index 00000000..c9955395
--- /dev/null
+++ b/frontend/src/components/SiteBanner.vue
@@ -0,0 +1,195 @@
+<template>
+  <!--
+    Two classes doing two different jobs. `page-contents` is what draws the markdown INSIDE the notice
+    -- its paragraphs, lists, links and code -- exactly as the same markdown would read on a page, and
+    is also what zeroes the notice's own outer margins (`> :first-child`, `> :last-child`).
+
+    The notice itself is drawn by `site-banner-alert` in the style block below, which is a COPY of the
+    caution admonition rather than a use of it: a banner is chrome an administrator raises over a
+    whole site, an admonition is something an author wrote in one page, and the two only happen to
+    look alike today. Restyle either without touching the other.
+  -->
+  <div class="page-contents site-banner" v-if="html" v-html="html" />
+</template>
+
+<script setup>
+import { computed, ref, watch } from 'vue'
+
+import { escape } from 'es-toolkit/string'
+
+import { useSiteStore } from '@/stores/site'
+
+/**
+ * The site-wide banner, above the contents of every page.
+ *
+ * Site configuration rather than content: it is set in the admin area's General section, is the same
+ * on every page, and so never goes through the page renderer -- which renders ONE page, on the server,
+ * and stores the result. This renders here instead, on every view, which is also what lets a banner
+ * raised during an incident appear without every page being re-rendered.
+ *
+ * Only the inline parts of markdown are worth anything in a notice a few lines long, but the full
+ * block grammar comes free with the parser, so the whole of markdown-it is what runs -- with `html`
+ * OFF, unlike the page renderer. An administrator writing a banner is not writing a page, and
+ * markdown-it's own link validation (`javascript:` and friends) is then the only escape left to
+ * worry about, which it handles itself.
+ */
+
+// STORES
+
+const siteStore = useSiteStore()
+
+// DATA
+
+/**
+ * The parser, built on first use and kept.
+ *
+ * Imported dynamically so that markdown-it stays out of the bundle a reader downloads for a site with
+ * no banner, which is nearly all of them -- and so that it is fetched alongside the banner rather than
+ * ahead of the page.
+ */
+let md = null
+
+/** Which render is the current one, so that a slower earlier import cannot land on top of a later. */
+let generation = 0
+
+const html = ref('')
+
+// COMPUTED
+
+const banner = computed(() => siteStore.banner)
+
+// WATCHERS
+
+watch(banner, render, { deep: true, immediate: true })
+
+// METHODS
+
+async function render() {
+  const gen = ++generation
+  const { isEnabled, title, content } = banner.value
+  if (!isEnabled) {
+    html.value = ''
+    return
+  }
+
+  // -> Text, not markdown: a title is one line, and a heading inside a heading is not what an
+  //    administrator typing a sentence there means
+  const parts = title ? [`<p class="site-banner-title">${escape(title)}</p>`] : []
+
+  if (content) {
+    md ??= new (await import('markdown-it')).default({
+      html: false,
+      linkify: true,
+      breaks: true
+    })
+    parts.push(md.render(content))
+  }
+
+  /*
+    Built as a string rather than written in the template around a `v-html` element, because the
+    title has to be a DIRECT child of the notice: an element in the template could only hold the
+    render in a wrapper of its own, and every `>` selector below would then miss.
+  */
+  if (gen === generation) {
+    html.value = parts.length > 0 ? `<div class="site-banner-alert">${parts.join('')}</div>` : ''
+  }
+}
+</script>
+
+<!--
+  Not scoped: the notice and its title are written by `v-html`, and scoped styles reach only the
+  elements Vue itself renders. Every selector is under `.site-banner`, which is what keeps it to this
+  component -- and what carries the specificity, since these rules sit inside `.page-contents` and
+  have to out-weigh its own (`.page-contents p` and friends are two components, so one class is not
+  enough).
+-->
+<style lang="scss">
+.site-banner {
+  /*
+    Flush to the top of the column, a hairline of it left showing either side, and the article's own
+    distance below.
+
+    All three are measured off the padding `page-container-body` puts around the article -- 1rem, or
+    0.5rem on a phone, which is why the breakpoint here is the 600px `Index.vue` switches that padding
+    at. The band takes the whole of it back at the top and all but a pixel of it at the sides, so the
+    property below is that padding and the margins are what is left of it.
+  */
+  --site-banner-pad: 1rem;
+
+  margin: calc(-1 * var(--site-banner-pad)) calc(1px - var(--site-banner-pad)) 1.5rem;
+
+  @media (max-width: $breakpoint-xs-max) {
+    --site-banner-pad: 0.5rem;
+  }
+
+  /*
+    Descended from the caution admonition in `css/_page-contents.scss` and now drawn on its own terms:
+    a wash, a heavier rule and an icon -- colour alone would leave a reader who cannot separate the
+    hues with nothing to go on, and the icon is a masked SVG rather than a glyph because the app ships
+    no icon webfont.
+
+    The rule runs along the BOTTOM and the corners are square, which is where it parts company with an
+    admonition: this is a band across the top of the page rather than a block within it, so it reads
+    as a strip the article begins under -- squared off to the column's own edges, and closed by a line
+    that says where the page's own content starts.
+
+    Its colours are declared here as the banner's OWN two properties rather than read from the content
+    palette, so that re-tinting the banner is these two lines (plus the two in the dark block) and
+    reaches nothing else.
+  */
+  .site-banner-alert {
+    --site-banner-hue: #c02636;
+    --site-banner-wash: rgba(192, 38, 54, 0.08);
+
+    position: relative;
+    padding: 0.9em 1.1em 0.9em 3.1em;
+    border-bottom: 4px solid var(--site-banner-hue);
+    background-color: var(--site-banner-wash);
+
+    /* -> Lighter, because the notice sits on a dark page rather than in the flow of one */
+    @at-root .body--dark & {
+      --site-banner-hue: #ff8b8b;
+      --site-banner-wash: rgba(255, 139, 139, 0.12);
+    }
+
+    &::before {
+      content: '';
+      position: absolute;
+      /*
+        Centred on the CAP BAND of the first line rather than on the line box holding it: a line box
+        is ascent plus descent, and a title inks only what is between the cap line and the baseline,
+        so an icon centred on the box reads as sitting a pixel high. `0.9em` is the padding above the
+        first line, `0.79em` the middle of the cap band within it, and `0.625em` half the icon.
+      */
+      top: calc(0.9em + 0.79em - 0.625em);
+      left: 1.1em;
+      width: 1.25em;
+      height: 1.25em;
+      /*
+        The warning triangle, drawn here as a mask rather than referenced as an icon: a name would be
+        resolved at runtime through `/_icons`, and a banner raised because something is wrong is the
+        last thing that should depend on a fetch.
+      */
+      background-color: var(--site-banner-hue);
+      mask-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24'%3E%3Cpath d='M13 14h-2V9h2m0 9h-2v-2h2M1 21h22L12 2z'/%3E%3C/svg%3E");
+      mask-repeat: no-repeat;
+      mask-size: contain;
+    }
+
+    /* -> The notice ends where its box does; the last block's own margin would show as a gap */
+    > :last-child {
+      margin-bottom: 0;
+    }
+
+    /*
+      The banner's heading, in the notice's colour since that is what it names, and close above the
+      text it introduces rather than a paragraph's distance from it.
+    */
+    > .site-banner-title {
+      margin-bottom: 0.3em;
+      color: var(--site-banner-hue);
+      font-weight: 600;
+    }
+  }
+}
+</style>
diff --git a/frontend/src/components/UtilCodeEditor.vue b/frontend/src/components/UtilCodeEditor.vue
index 57e122ec..bc85e00b 100644
--- a/frontend/src/components/UtilCodeEditor.vue
+++ b/frontend/src/components/UtilCodeEditor.vue
@@ -49,6 +49,7 @@ import hljs from 'highlight.js/lib/core'
 import css from 'highlight.js/lib/languages/css'
 import javascript from 'highlight.js/lib/languages/javascript'
 import json from 'highlight.js/lib/languages/json'
+import markdown from 'highlight.js/lib/languages/markdown'
 import xml from 'highlight.js/lib/languages/xml'
 import yaml from 'highlight.js/lib/languages/yaml'
 
@@ -59,7 +60,10 @@ const props = defineProps({
     type: String,
     default: ''
   },
-  /** `css` | `html` | `javascript` | `json` | `yaml`; anything else renders unhighlighted. */
+  /**
+   * `css` | `html` | `javascript` | `json` | `markdown` | `yaml`; anything else renders
+   * unhighlighted.
+   */
   language: {
     type: String,
     default: 'plaintext'
@@ -102,6 +106,7 @@ const inputEl = ref(null)
 hljs.registerLanguage('css', css)
 hljs.registerLanguage('javascript', javascript)
 hljs.registerLanguage('json', json)
+hljs.registerLanguage('markdown', markdown)
 hljs.registerLanguage('xml', xml)
 hljs.registerLanguage('yaml', yaml)
 
@@ -115,6 +120,7 @@ const HLJS_LANGUAGES = {
   html: 'xml',
   javascript: 'javascript',
   json: 'json',
+  markdown: 'markdown',
   yaml: 'yaml'
 }
 
diff --git a/frontend/src/components/shared/WItem.vue b/frontend/src/components/shared/WItem.vue
index 1681230b..f70e10a0 100644
--- a/frontend/src/components/shared/WItem.vue
+++ b/frontend/src/components/shared/WItem.vue
@@ -66,7 +66,14 @@ const props = defineProps({
     type: Boolean,
     default: false
   },
-  /** Underlying element when this is not a link. */
+  /**
+   * Underlying element when this is not a link.
+   *
+   * Nullable, and null means the default rather than nothing. Callers write
+   * `:tag="condition ? 'label' : null"` to say "a label only when the row is operable", and a prop
+   * default does not cover that: Vue applies one for `undefined` alone, so the null arrived intact
+   * and `<component :is="null">` rendered the row away to nothing. See `tagName`.
+   */
   tag: {
     type: String,
     default: 'div'
@@ -105,7 +112,8 @@ const showsAffordance = computed(
 // -> A disabled link must stop being a link, or the browser will still navigate on click
 const tagName = computed(() => {
   if (!isAnchor.value) {
-    return props.tag
+    // -> `?? 'div'` rather than the prop default, which Vue only applies to `undefined`; see `tag`
+    return props.tag ?? 'div'
   }
   return props.to ? 'router-link' : 'a'
 })
diff --git a/frontend/src/components/shared/WSelect.vue b/frontend/src/components/shared/WSelect.vue
index 8c549957..8572a596 100644
--- a/frontend/src/components/shared/WSelect.vue
+++ b/frontend/src/components/shared/WSelect.vue
@@ -162,18 +162,19 @@
             class="w-select-option flex w-full cursor-pointer flex-nowrap items-center gap-2 px-4 text-left hover:bg-black/5 dark:hover:bg-white/8"
             :class="[
               optionsDense ? 'min-h-8 py-1 text-body2' : 'min-h-10 py-2',
-              isSelected(opt.value) ? 'text-primary' : '',
+              isSelected(opt.value) ? selectedOptionClass : '',
               idx === activeIndex ? 'bg-black/8 dark:bg-white/12' : ''
             ]"
             @click.stop="select(opt.value)"
             @mousemove="activeIndex = idx">
             <!--
               A check, not a checkbox. The icon takes the row's own font size unless told otherwise,
-              which made a 14px square that read as a rendering fault rather than a control -- and the
-              row already announces its state by colouring itself. The column is held open when
-              nothing is drawn, so labels line up whatever is selected.
+              which made a 14px square that read as a rendering fault rather than a control. Drawn for
+              a single selection too: colour alone is a weak marker, and the one the row used to rely
+              on could not be strong enough on a dark panel to carry the state by itself. The column is
+              held open when nothing is drawn, so labels line up whatever is selected.
             -->
-            <span v-if="multiple" class="flex w-5 shrink-0 justify-center">
+            <span class="flex w-5 shrink-0 justify-center">
               <w-icon v-if="isSelected(opt.value)" name="mdi:check" size="20px" />
             </span>
             <span class="min-w-0 flex-1">
@@ -747,6 +748,17 @@ const floatColorClass = computed(() => {
   return isOpen.value ? 'text-primary dark:text-primary-light' : 'text-black/60 dark:text-white/70'
 })
 
+/*
+  Brand blue is a *dark* colour, so on the dark panel it sat at roughly 3:1 against `dark-3` and the
+  selected row read as the least legible one in the list. The lightened blue is the same colour the
+  floating label and `.w-section-header` switch to on dark, and it carries the emphasis without the
+  contrast loss. `dark` is checked separately from the `dark:` variant because a menu opened from a
+  dark surface renders dark whatever the app theme -- which is exactly the admin sidebar's case.
+*/
+const selectedOptionClass = computed(() =>
+  props.dark ? 'text-primary-light' : 'text-primary dark:text-primary-light'
+)
+
 const controlClasses = computed(() => [
   props.dense ? 'w-input-control--dense min-h-9 px-2 py-1' : 'min-h-11 px-3 py-2',
   // -> Its own surface, white or a dark well, matching WInput; see the note there
diff --git a/frontend/src/pages/AdminDashboard.vue b/frontend/src/pages/AdminDashboard.vue
index ab857a1c..96f7a5ab 100644
--- a/frontend/src/pages/AdminDashboard.vue
+++ b/frontend/src/pages/AdminDashboard.vue
@@ -19,7 +19,7 @@
           flat
           color="grey"
           :aria-label="t(`common.actions.viewDocs`)"
-          :href="siteStore.docsBase + `/admin`"
+          :href="siteStore.docsBase + `/admin/dashboard`"
           target="_blank">
           <w-tooltip>{{ t(`common.actions.viewDocs`) }}</w-tooltip>
         </w-btn>
diff --git a/frontend/src/pages/AdminGeneral.vue b/frontend/src/pages/AdminGeneral.vue
index fa14f830..8f8a2378 100644
--- a/frontend/src/pages/AdminGeneral.vue
+++ b/frontend/src/pages/AdminGeneral.vue
@@ -415,6 +415,55 @@
           </w-item>
         </w-card>
         <!-- ----------------------- -->
+        <!-- Site-wide Banner -->
+        <!-- ----------------------- -->
+        <w-card class="pb-2 mt-4">
+          <w-card-header>{{ t('admin.general.banner') }}</w-card-header>
+          <w-item tag="label">
+            <blueprint-icon icon="flag-filled" />
+            <w-item-section>
+              <w-item-label>{{ t(`admin.general.bannerEnabled`) }}</w-item-label>
+              <w-item-label caption>{{ t(`admin.general.bannerEnabledHint`) }}</w-item-label>
+            </w-item-section>
+            <w-item-section avatar>
+              <w-toggle
+                v-model="state.config.banner.isEnabled"
+                :aria-label="t(`admin.general.bannerEnabled`)" />
+            </w-item-section>
+          </w-item>
+          <w-separator class="my-2" inset />
+          <w-item>
+            <blueprint-icon icon="typography" />
+            <w-item-section>
+              <w-item-label>{{ t(`admin.general.bannerTitle`) }}</w-item-label>
+              <w-item-label caption>{{ t(`admin.general.bannerTitleHint`) }}</w-item-label>
+            </w-item-section>
+            <w-item-section>
+              <w-input
+                outlined
+                v-model="state.config.banner.title"
+                dense
+                :aria-label="t(`admin.general.bannerTitle`)" />
+            </w-item-section>
+          </w-item>
+          <w-separator class="my-2" inset />
+          <w-item>
+            <blueprint-icon icon="markdown" class="self-start" />
+            <w-item-section>
+              <w-item-label>{{ t(`admin.general.bannerContent`) }}</w-item-label>
+              <w-item-label caption>{{ t(`admin.general.bannerContentHint`) }}</w-item-label>
+            </w-item-section>
+          </w-item>
+          <w-item>
+            <w-item-section>
+              <util-code-editor
+                v-model="state.config.banner.content"
+                language="markdown"
+                :aria-label="t(`admin.general.bannerContent`)" />
+            </w-item-section>
+          </w-item>
+        </w-card>
+        <!-- ----------------------- -->
         <!-- Discovery -->
         <!-- ----------------------- -->
         <w-card class="pb-2 mt-4">
@@ -538,6 +587,8 @@ import { loading } from '@/composables/loading'
 import { useAdminStore } from '@/stores/admin'
 import { useSiteStore } from '@/stores/site'
 
+import UtilCodeEditor from '@/components/UtilCodeEditor.vue'
+
 import {
   clearSiteImage,
   isAcceptedSiteImage,
@@ -576,6 +627,11 @@ function defaultConfig() {
     company: '',
     contentLicense: '',
     footerExtra: '',
+    banner: {
+      isEnabled: false,
+      title: '',
+      content: ''
+    },
     pageExtensions: '',
     logoText: false,
     ratings: {
@@ -695,6 +751,11 @@ async function save() {
         company: state.config.company ?? '',
         contentLicense: state.config.contentLicense ?? '',
         footerExtra: state.config.footerExtra ?? '',
+        banner: {
+          isEnabled: state.config.banner?.isEnabled ?? false,
+          title: state.config.banner?.title ?? '',
+          content: state.config.banner?.content ?? ''
+        },
         pageExtensions: parsePageExtensions(state.config.pageExtensions),
         logoText: state.config.logoText ?? false,
         sitemap: state.config.sitemap ?? false,
diff --git a/frontend/src/pages/Index.vue b/frontend/src/pages/Index.vue
index 1805fc3f..c5acca8a 100644
--- a/frontend/src/pages/Index.vue
+++ b/frontend/src/pages/Index.vue
@@ -115,6 +115,11 @@
           <!-- -> Half the padding on a phone, where 16px a side is 8% of the window spent on margin;
                   the stylesheet has `--content-bleed` to match -->
           <div class="page-container-body p-2 sm:p-4">
+            <!--
+              Above the article rather than above the toolbars: what an administrator raises a banner
+              about is the content, and this is where a reader is already looking.
+            -->
+            <site-banner />
             <!--
               Delegated rather than bound per link: the anchors are written by `v-html`, so there is
               nothing here to put a handler on, and they are replaced wholesale on every render.
@@ -363,6 +368,7 @@ import PageTags from '@/components/PageTags.vue'
 import PageToc from '@/components/PageToc.vue'
 import PageUnlockDialog from '@/components/PageUnlockDialog.vue'
 import SideDialog from '@/components/SideDialog.vue'
+import SiteBanner from '@/components/SiteBanner.vue'
 
 const editorComponents = {
   markdown: defineAsyncComponent({
@@ -1058,13 +1064,22 @@ $toc-overlay-max: 749.98px;
   }
 }
 
+/*
+  A hairline of the page's OWN background between the header and whatever the column starts with, in
+  each theme's colour -- so it is invisible against the article, which is that colour, and reads as one
+  pixel of daylight under anything that starts flush to the top of the column. A site banner does
+  exactly that, and against the header's bottom border it needs the gap.
+
+  Both themes: with the dark one left out the banner butted straight into the header there and not in
+  the light theme, which is the sort of difference that reads as a bug in whichever one you see second.
+*/
 .page-container {
   @at-root .body--light & {
     border-top: 1px solid #fff;
   }
-  // @at-root .body--dark & {
-  //   border-top: 1px solid $dark-6;
-  // }
+  @at-root .body--dark & {
+    border-top: 1px solid $dark-6;
+  }
 }
 /*
   The Tags heading's edit toggle. `visibility` is transitioned alongside the opacity so it still fades
diff --git a/frontend/src/stores/site.js b/frontend/src/stores/site.js
index 554889f5..b7d9e35c 100644
--- a/frontend/src/stores/site.js
+++ b/frontend/src/stores/site.js
@@ -47,6 +47,16 @@ export const useSiteStore = defineStore('site', {
     company: '',
     contentLicense: '',
     footerExtra: '',
+    /**
+     * The notice an administrator can raise above the contents of every page — an outage, a freeze,
+     * a wiki being moved. `content` is markdown, rendered by `SiteBanner.vue` at display time rather
+     * than stored as HTML: it is site configuration, and never goes through the page renderer.
+     */
+    banner: {
+      isEnabled: false,
+      title: '',
+      content: ''
+    },
     dark: false,
     title: '',
     description: '',
@@ -191,6 +201,10 @@ export const useSiteStore = defineStore('site', {
         company: siteInfo.company,
         contentLicense: siteInfo.contentLicense,
         footerExtra: siteInfo.footerExtra,
+        banner: {
+          ...this.banner,
+          ...siteInfo.banner
+        },
         features: {
           ...this.features,
           ...siteInfo.features