diff --git a/app.vue b/app.vue
index 3b53cda..7b07ac8 100644
--- a/app.vue
+++ b/app.vue
@@ -1,12 +1,12 @@
 <template>
   <div class="flex flex-col h-screen overflow-hidden" :class="{ dark: isDark }" style="background: var(--nav-bg);">
 
-    <!-- ═══════════════════════════════════════ TOP NAV GLOBAL -->
+    <!-- ═══════════════════════════════════════ TOP NAV GLOBAL (B10 : échelles S / M / XL) -->
     <header
-      class="flex items-center justify-between px-4 py-2.5 shrink-0 relative z-[9999] shadow-sm gap-3"
+      class="app-header flex items-center px-4 shrink-0 relative z-[9999] shadow-sm gap-3"
       style="background: var(--nav-surface); border-bottom: 1px solid var(--nav-bg-alt);"
     >
-      <!-- Logo -->
+      <!-- Logo : texte complet sauf 768-1023 et 1280-1439 (place des onglets) -->
       <a href="/" class="logo-link flex items-center gap-2 hover:opacity-90 transition-opacity shrink-0" title="Architecture d'Écologie Politique">
         <div
           class="h-8 px-2 rounded-lg flex items-center justify-center shrink-0"
@@ -20,112 +20,38 @@
         </div>
       </a>
 
-      <!-- ── Onglets desktop (≥1024px) — remplace la barre de recherche ── -->
-      <nav class="hidden lg:flex flex-1 justify-center items-end gap-0 mx-6" aria-label="Navigation projets">
-        <NuxtLink
-          to="/outils"
-          class="nav-tab"
-          :class="{ 'nav-tab--active': route.path === '/outils' }"
-        >
-          Outils
-        </NuxtLink>
-        <NuxtLink
-          to="/"
-          class="nav-tab"
-          :class="{ 'nav-tab--active': route.path === '/' }"
-        >
-          Écosystème Entraide
-        </NuxtLink>
-        <NuxtLink
-          to="/agences"
-          class="nav-tab"
-          :class="{ 'nav-tab--active': route.path === '/agences' }"
-        >
-          Réseaux AEP
-        </NuxtLink>
-        <NuxtLink
-          to="/trouver-du-taf"
-          class="nav-tab"
-          :class="{ 'nav-tab--active': route.path === '/trouver-du-taf' }"
-        >
-          Jobs
-        </NuxtLink>
-        <NuxtLink
-          to="/codev"
-          class="nav-tab"
-          :class="{ 'nav-tab--active': route.path.startsWith('/codev') }"
-        >
-          Codev
-        </NuxtLink>
-        <NuxtLink
-          to="/media"
-          class="nav-tab"
-          :class="{ 'nav-tab--active': route.path.startsWith('/media') }"
-        >
-          recherche-média
-        </NuxtLink>
-      </nav>
-
-      <!-- ── Barre recherche mobile (640px–1024px) — masquée < 640px car accessible dans la sheet -->
-      <div class="hidden sm:flex lg:hidden flex-1 mx-2">
-        <label class="flex items-center gap-2 w-full px-3 py-1.5 rounded-xl border" style="background: var(--nav-bg); border-color: var(--nav-bg-alt);">
-          <svg width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true" style="color: var(--nav-text-muted); flex-shrink: 0;">
-            <circle cx="11" cy="11" r="8"/>
-            <line x1="21" y1="21" x2="16.65" y2="16.65"/>
-          </svg>
-          <input
-            v-model="headerSearch"
-            type="search"
-            placeholder="Rechercher…"
-            class="flex-1 bg-transparent border-0 outline-none text-sm"
-            style="color: var(--nav-text); font-family: var(--nav-font);"
-            autocomplete="off"
-            @input="onHeaderSearch"
-            @keydown.enter="onHeaderSearch"
-          />
-          <button
-            v-if="headerSearch"
-            type="button"
-            @click.stop="clearHeaderSearch"
-            class="flex-shrink-0"
-            style="color: var(--nav-text-muted);"
-            aria-label="Effacer la recherche"
-          >
-            <svg width="13" height="13" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round">
-              <line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/>
-            </svg>
-          </button>
-        </label>
-      </div>
+      <!-- Échelles : trois groupes ≥ 1280, groupe courant 768-1279, rien < 768 (fil d'échelle) -->
+      <NavEchelles />
+      <div class="flex-1 md:hidden" aria-hidden="true" />
 
       <!-- Actions droite -->
       <div class="flex items-center gap-2 shrink-0">
         <NuxtLink
           to="/manifeste"
-          class="px-3 py-1.5 rounded-lg text-sm font-medium transition-all hover:opacity-80 hidden md:inline-flex items-center gap-1"
-          :style="route.path === '/manifeste' ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text-muted);'"
+          class="header-lien hidden md:inline-flex"
+          :aria-current="route.path === '/manifeste' ? 'page' : undefined"
         >
           Manifeste
         </NuxtLink>
         <NuxtLink
           to="/a-propos"
-          class="px-3 py-1.5 rounded-lg text-sm font-medium transition-all hover:opacity-80 hidden md:inline-flex items-center gap-1"
-          style="color: var(--nav-text-muted);"
+          class="header-lien header-xl"
+          :aria-current="route.path === '/a-propos' ? 'page' : undefined"
         >
           À propos
         </NuxtLink>
-        <NuxtLink
-          to="/signaler"
-          class="px-3 py-1.5 rounded-lg text-sm font-medium transition-all hover:opacity-80 hidden lg:inline-flex items-center gap-1"
-          style="color: var(--nav-text-muted);"
+        <a
+          :href="SOUTENIR_URL"
+          target="_blank"
+          rel="noopener noreferrer"
+          class="header-soutenir header-xl"
         >
-          Signaler
-        </NuxtLink>
-        <!-- Proposer une ressource (5 onglets) -->
+          Soutenir
+        </a>
+        <!-- Proposer une ressource -->
         <NuxtLink
           to="/proposer"
-          class="px-3 py-1.5 rounded-lg text-sm font-semibold transition-all hover:opacity-80 hidden sm:inline-flex items-center gap-1"
-          style="background: var(--nav-accent); color: var(--nav-text);"
+          class="header-proposer hidden md:inline-flex"
         >
           + Proposer
         </NuxtLink>
@@ -153,68 +79,51 @@
         <!-- Mobile : proposer icône -->
         <NuxtLink
           to="/proposer"
-          class="sm:hidden p-2 rounded-lg"
-          style="background: var(--nav-accent); color: var(--nav-text);"
+          class="md:hidden p-2 rounded-lg"
+          style="background: var(--accent); color: var(--on-accent);"
           title="Proposer une ressource"
           aria-label="Proposer"
         >
-          <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round">
+          <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" stroke-linejoin="round" aria-hidden="true">
             <line x1="12" y1="5" x2="12" y2="19"/><line x1="5" y1="12" x2="19" y2="12"/>
           </svg>
         </NuxtLink>
 
-        <!-- Menu déroulant — toutes largeurs (les onglets n'y apparaissent qu'en dessous de 1024px) ; porte « Soutenir » -->
-        <div class="relative">
-          <button
-            @click="hamburgerOpen = !hamburgerOpen"
-            class="p-2 rounded-lg transition-all hover:opacity-80"
-            style="background: var(--nav-bg-alt); color: var(--nav-text-muted);"
-            :aria-label="hamburgerOpen ? 'Fermer le menu' : 'Menu'"
-            :aria-expanded="hamburgerOpen"
-          >
-            <svg v-if="!hamburgerOpen" width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" aria-hidden="true">
-              <line x1="3" y1="6" x2="21" y2="6"/><line x1="3" y1="12" x2="21" y2="12"/><line x1="3" y1="18" x2="21" y2="18"/>
-            </svg>
-            <svg v-else width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" aria-hidden="true">
-              <line x1="18" y1="6" x2="6" y2="18"/><line x1="6" y1="6" x2="18" y2="18"/>
-            </svg>
-          </button>
-          <div
-            v-if="hamburgerOpen"
-            class="absolute right-0 top-full mt-1 rounded-lg shadow-lg min-w-[210px] py-1"
-            style="background: var(--nav-surface); border: 1px solid var(--nav-bg-alt); z-index: 9999;"
-            @click="hamburgerOpen = false"
-          >
-            <NuxtLink to="/outils" class="lg:hidden block px-4 py-2.5 text-sm font-medium transition-opacity hover:opacity-70" :style="route.path === '/outils' ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text);'">Outils</NuxtLink>
-            <NuxtLink to="/" class="lg:hidden block px-4 py-2.5 text-sm font-medium transition-opacity hover:opacity-70" :style="route.path === '/' ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text);'">Écosystème Entraide</NuxtLink>
-            <NuxtLink to="/agences" class="lg:hidden block px-4 py-2.5 text-sm transition-opacity hover:opacity-70" :style="route.path === '/agences' ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text);'">Réseaux AEP</NuxtLink>
-            <NuxtLink to="/trouver-du-taf" class="lg:hidden block px-4 py-2.5 text-sm transition-opacity hover:opacity-70" :style="route.path === '/trouver-du-taf' ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text);'">Jobs</NuxtLink>
-            <NuxtLink to="/media" class="lg:hidden block px-4 py-2.5 text-sm transition-opacity hover:opacity-70" :style="route.path.startsWith('/media') ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text);'">recherche-média</NuxtLink>
-            <NuxtLink to="/codev" class="lg:hidden block px-4 py-2.5 text-sm transition-opacity hover:opacity-70" :style="route.path.startsWith('/codev') ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text);'">Codev</NuxtLink>
-            <div class="lg:hidden" style="height: 1px; background: var(--nav-bg-alt); margin: 4px 0;"></div>
-            <NuxtLink to="/manifeste" class="block px-4 py-2.5 text-sm transition-opacity hover:opacity-70" :style="route.path === '/manifeste' ? 'color: var(--nav-primary-solid); font-weight: 700;' : 'color: var(--nav-text-muted);'">Manifeste</NuxtLink>
-            <NuxtLink to="/a-propos" class="block px-4 py-2.5 text-sm transition-opacity hover:opacity-70" style="color: var(--nav-text-muted);">À propos</NuxtLink>
-            <a href="https://liberapay.com/trans-former.fr/donate" target="_blank" rel="noopener noreferrer" class="block mx-3 my-2 px-4 py-2 rounded-lg text-sm font-semibold text-center transition-opacity hover:opacity-80" style="background: var(--nav-accent); color: var(--nav-text);">Soutenir</a>
-            <NuxtLink to="/signaler" class="block px-4 py-2.5 text-sm transition-opacity hover:opacity-70" style="color: var(--nav-text-muted);">Signaler</NuxtLink>
-          </div>
-        </div>
+        <!-- Menu (< 1280) : ouvre le tiroir ; le mot est écrit à partir de 768 -->
+        <button
+          type="button"
+          class="header-menu"
+          aria-label="Ouvrir le menu"
+          aria-haspopup="dialog"
+          :aria-expanded="menuOpen"
+          @click="menuOpen = true"
+        >
+          <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" aria-hidden="true">
+            <line x1="3" y1="6" x2="21" y2="6"/><line x1="3" y1="12" x2="21" y2="12"/><line x1="3" y1="18" x2="21" y2="18"/>
+          </svg>
+          <span class="header-menu__mot" aria-hidden="true">Menu</span>
+        </button>
       </div>
     </header>
 
+    <!-- Fil d'échelle (< 768) : dans le flux de la colonne, hors du conteneur de page -->
+    <FilEchelle />
+
     <!-- Contenu page (flex-1 pour remplir l'espace) -->
-    <div class="flex-1" :class="route.path === '/' ? 'overflow-hidden' : 'overflow-y-auto'">
+    <div class="flex-1 min-h-0" :class="route.path === '/' ? 'overflow-hidden' : 'overflow-y-auto'">
       <NuxtPage />
     </div>
 
+    <NavTiroir :open="menuOpen" @close="menuOpen = false" />
   </div>
 </template>
 
 <script setup lang="ts">
-const router = useRouter()
+import { SOUTENIR_URL } from '~/utils/liens'
+
 const route = useRoute()
 
-const hamburgerOpen = ref(false)
-watch(() => route.path, () => { hamburgerOpen.value = false })
+const menuOpen = ref(false)
 
 // ── Dark mode ─────────────────────────────────────────────────────────────
 const isDark = ref(false)
@@ -237,40 +146,14 @@ function toggleDark() {
     localStorage.setItem('aep_theme', 'light')
   }
 }
-
-// ── Barre de recherche header mobile ─────────────────────────────────────
-const headerSearch = ref((route.query.q as string) ?? '')
-
-// Sync depuis URL quand la route change
-watch(() => route.query.q, (v) => {
-  headerSearch.value = (v as string) ?? ''
-})
-
-function onHeaderSearch() {
-  const q = headerSearch.value.trim()
-  if (route.path === '/') {
-    router.replace({ query: q ? { ...route.query, q } : { ...route.query, q: undefined } })
-  } else if (q) {
-    router.push({ path: '/', query: { q } })
-  }
-}
-
-function clearHeaderSearch() {
-  headerSearch.value = ''
-  if (route.path === '/') {
-    const q = { ...route.query }
-    delete q.q
-    router.replace({ query: Object.keys(q).length ? q : undefined })
-  }
-}
-
-// ── Fiche aléatoire ───────────────────────────────────────────────────────
-function goRandom() {
-  router.push({ path: '/', query: { random: '1' } })
-}
 </script>
 
 <style>
+/* ── En-tête ──────────────────────────────────────────────────────────── */
+.app-header {
+  min-height: 52px;
+}
+
 /* ── Logo header (texte 2 lignes) ─────────────────────────────────────── */
 .logo-text {
   line-height: 1.05;
@@ -285,39 +168,96 @@ function goRandom() {
 @media (min-width: 1024px) {
   .logo-line-1, .logo-line-2 { font-size: 0.85rem; }
 }
+/* Le groupe courant (768-1023) et les trois groupes (1280-1439) prennent la place du texte */
+@media (min-width: 768px) and (max-width: 1023px), (min-width: 1280px) and (max-width: 1439px) {
+  .logo-text { display: none; }
+}
 
-/* ── Onglets header desktop ───────────────────────────────────────────── */
-.nav-tab {
-  position: relative;
-  display: inline-flex;
-  flex-direction: column;
+/* ── Liens et boutons de droite ───────────────────────────────────────── */
+.header-lien {
   align-items: center;
-  padding: 6px 16px 8px;
-  font-size: 0.8rem;
-  font-weight: 500;
-  color: var(--nav-text-muted);
+  padding: 6px 8px;
+  border-radius: var(--radius-md);
+  font-size: var(--fs-sm);
+  font-weight: var(--fw-medium);
+  white-space: nowrap;
   text-decoration: none;
-  transition: color 0.15s;
-  border-bottom: 2px solid transparent;
-  gap: 2px;
+  color: color-mix(in srgb, var(--text) 78%, transparent);
+}
+.header-lien:hover,
+.header-lien[aria-current="page"] {
+  color: var(--text);
+}
+.header-lien[aria-current="page"] {
+  font-weight: var(--fw-bold);
 }
 
-.nav-tab:hover {
-  color: var(--nav-text);
+.header-soutenir {
+  align-items: center;
+  padding: 5px 10px;
+  border: 1.5px solid var(--accent);
+  border-radius: var(--radius-md);
+  font-size: var(--fs-sm);
+  font-weight: var(--fw-semibold);
+  white-space: nowrap;
+  text-decoration: none;
+  color: var(--text);
 }
 
-.nav-tab--active {
-  color: var(--nav-text);
-  border-bottom-color: var(--nav-primary-solid);
-  font-weight: 600;
+.header-proposer {
+  align-items: center;
+  padding: 6px 11px;
+  border-radius: var(--radius-md);
+  background: var(--accent);
+  color: var(--on-accent);
+  font-size: var(--fs-sm);
+  font-weight: var(--fw-semibold);
+  white-space: nowrap;
+  text-decoration: none;
 }
 
-.nav-tab-badge {
-  font-size: 0.6rem;
-  font-weight: 600;
-  text-transform: uppercase;
-  letter-spacing: 0.04em;
-  color: var(--nav-text-muted);
-  opacity: 0.65;
+.header-soutenir:hover,
+.header-proposer:hover {
+  opacity: 0.85;
+}
+
+.header-lien:focus-visible,
+.header-soutenir:focus-visible,
+.header-proposer:focus-visible,
+.header-menu:focus-visible {
+  outline: 2px solid var(--focus-ring);
+  outline-offset: 2px;
+}
+
+/* À propos et Soutenir : barre complète seulement (≥ 1280), sinon dans le tiroir */
+.header-xl { display: none; }
+@media (min-width: 1280px) {
+  .header-xl { display: inline-flex; }
+}
+
+.header-menu {
+  display: inline-flex;
+  align-items: center;
+  gap: 6px;
+  padding: 8px;
+  border: 1px solid transparent;
+  border-radius: var(--radius-md);
+  background: var(--bg-alt);
+  color: var(--text);
+  font-size: var(--fs-sm);
+  font-weight: var(--fw-semibold);
+  cursor: pointer;
+}
+.header-menu__mot { display: none; }
+@media (min-width: 768px) {
+  .header-menu {
+    padding: 5px 10px;
+    border-color: var(--border);
+    background: transparent;
+  }
+  .header-menu__mot { display: inline; }
+}
+@media (min-width: 1280px) {
+  .header-menu { display: none; }
 }
 </style>
diff --git a/components/FilEchelle.vue b/components/FilEchelle.vue
new file mode 100644
index 0000000..34d98ef
--- /dev/null
+++ b/components/FilEchelle.vue
@@ -0,0 +1,84 @@
+<!--
+  FilEchelle — B10-M4
+  < 768 px : une ligne de 28 px sous la barre, « S · Partir de soi · Outils · Jobs » :
+  l'échelle courante, l'onglet courant, puis ses voisins du groupe (liens).
+  Absente sur les pages hors groupe (Manifeste, À propos, Proposer, Signaler, fiche).
+  Montée dans le flux de la colonne d'app.vue, AVANT le conteneur de page : la carte
+  de / perd ces 28 px à vue, jamais en dessous de la ligne de flottaison.
+-->
+<template>
+  <nav v-if="courant" class="fil-echelle" aria-label="Échelle courante">
+    <span class="fil-echelle__pastille">{{ courant.echelle }}</span>
+    <span class="fil-echelle__titre">{{ ECHELLES[courant.echelle].titre }}</span>
+    <span class="fil-echelle__sep" aria-hidden="true">·</span>
+    <span class="fil-echelle__courant" aria-current="page">{{ courant.onglet.libelle }}</span>
+    <template v-for="o in voisins" :key="o.to">
+      <span class="fil-echelle__sep" aria-hidden="true">·</span>
+      <NuxtLink :to="o.to" class="fil-echelle__lien">{{ o.libelle }}</NuxtLink>
+    </template>
+  </nav>
+</template>
+
+<script setup lang="ts">
+import { ECHELLES, echelleDeRoute } from '~/utils/echelles'
+
+const route = useRoute()
+const courant = computed(() => echelleDeRoute(route))
+const voisins = computed(() =>
+  courant.value ? ECHELLES[courant.value.echelle].onglets.filter((o) => o !== courant.value!.onglet) : [],
+)
+</script>
+
+<style scoped>
+.fil-echelle {
+  display: flex;
+  align-items: center;
+  flex-shrink: 0;
+  height: 28px;
+  padding: 0 var(--space-sm);
+  gap: 5px;
+  overflow-x: auto;
+  scrollbar-width: none;
+  white-space: nowrap;
+  font-size: 0.72rem;
+  line-height: 1;
+  background: var(--surface);
+  border-bottom: 1px solid var(--bg-alt);
+  color: color-mix(in srgb, var(--text) 78%, transparent);
+}
+
+.fil-echelle::-webkit-scrollbar {
+  display: none;
+}
+
+.fil-echelle__pastille {
+  padding: 2px 5px;
+  border-radius: var(--radius-sm);
+  background: var(--accent);
+  color: var(--on-accent);
+  font-weight: var(--fw-bold);
+}
+
+.fil-echelle__courant {
+  font-weight: var(--fw-bold);
+  color: var(--text);
+}
+
+.fil-echelle__lien {
+  color: inherit;
+  text-decoration: underline;
+  text-decoration-color: var(--border);
+  text-underline-offset: 3px;
+}
+
+.fil-echelle__lien:focus-visible {
+  outline: 2px solid var(--focus-ring);
+  outline-offset: 1px;
+}
+
+@media (min-width: 768px) {
+  .fil-echelle {
+    display: none;
+  }
+}
+</style>
diff --git a/components/NavEchelles.vue b/components/NavEchelles.vue
new file mode 100644
index 0000000..3ad272c
--- /dev/null
+++ b/components/NavEchelles.vue
@@ -0,0 +1,148 @@
+<!--
+  NavEchelles — B10-M2
+  Barre des trois échelles S / M / XL, lue depuis utils/echelles.ts (source unique).
+  ≥ 1280 px : les trois groupes ; 768-1279 px : le seul groupe de la page courante ;
+  < 768 px : rien (FilEchelle + NavTiroir prennent le relais).
+  Chaque groupe = <ul> étiqueté par son accroche (pastille + titre de l'échelle).
+-->
+<template>
+  <nav class="nav-echelles" aria-label="Échelles">
+    <div
+      v-for="id in ORDRE_ECHELLES"
+      :key="id"
+      class="nav-echelles__grp"
+      :class="{ 'nav-echelles__grp--courant': courant?.echelle === id }"
+    >
+      <span :id="`nav-echelle-${id}`" class="nav-echelles__kick">
+        <span class="nav-echelles__pastille">{{ id }}</span>{{ ECHELLES[id].titre }}
+      </span>
+      <ul class="nav-echelles__tabs" :aria-labelledby="`nav-echelle-${id}`">
+        <li v-for="o in ECHELLES[id].onglets" :key="o.to">
+          <NuxtLink
+            :to="o.to"
+            class="nav-echelles__tab"
+            :class="{ 'nav-echelles__tab--actif': o.actif(route) }"
+            :aria-current="o.actif(route) ? 'page' : undefined"
+          >{{ o.libelle }}</NuxtLink>
+        </li>
+      </ul>
+    </div>
+  </nav>
+</template>
+
+<script setup lang="ts">
+import { ECHELLES, ORDRE_ECHELLES, echelleDeRoute } from '~/utils/echelles'
+
+const route = useRoute()
+const courant = computed(() => echelleDeRoute(route))
+</script>
+
+<style scoped>
+.nav-echelles {
+  display: none;
+  align-self: stretch;
+  flex: 1 1 auto;
+  min-width: 0;
+  gap: var(--space-lg);
+}
+
+.nav-echelles__grp {
+  position: relative;
+  display: none;
+  flex-direction: column;
+  justify-content: flex-end;
+  min-width: 0;
+}
+
+.nav-echelles__kick {
+  padding: 0 var(--space-xs);
+  font-size: 0.66rem;
+  font-weight: var(--fw-semibold);
+  letter-spacing: 0.04em;
+  line-height: 1.3;
+  white-space: nowrap;
+  color: color-mix(in srgb, var(--text) 78%, transparent);
+}
+
+.nav-echelles__grp--courant .nav-echelles__kick {
+  color: var(--text);
+}
+
+.nav-echelles__pastille {
+  display: inline-block;
+  margin-right: 5px;
+  padding: 0 5px;
+  border-radius: var(--radius-sm);
+  background: var(--accent);
+  color: var(--on-accent);
+  font-weight: var(--fw-bold);
+}
+
+.nav-echelles__tabs {
+  display: flex;
+  margin: 0;
+  padding: 0;
+  list-style: none;
+}
+
+.nav-echelles__tab {
+  display: inline-block;
+  padding: 4px 9px 9px;
+  font-size: 0.8rem;
+  font-weight: var(--fw-medium);
+  white-space: nowrap;
+  text-decoration: none;
+  color: color-mix(in srgb, var(--text) 78%, transparent);
+  border-bottom: 2px solid transparent;
+  transition: color var(--dur-fast) var(--ease-out);
+}
+
+.nav-echelles__tab:hover {
+  color: var(--text);
+}
+
+.nav-echelles__tab:focus-visible {
+  outline: 2px solid var(--focus-ring);
+  outline-offset: -2px;
+  border-radius: var(--radius-sm);
+}
+
+.nav-echelles__tab--actif {
+  color: var(--text);
+  font-weight: var(--fw-semibold);
+  border-bottom-color: var(--nav-primary-solid);
+}
+
+/* 768-1279 : le seul groupe courant, aligné à gauche après le logo */
+@media (min-width: 768px) {
+  .nav-echelles {
+    display: flex;
+    justify-content: flex-start;
+  }
+  .nav-echelles__grp--courant {
+    display: flex;
+  }
+}
+
+/* ≥ 1280 : les trois groupes, centrés, séparés par un filet */
+@media (min-width: 1280px) {
+  .nav-echelles {
+    justify-content: center;
+  }
+  .nav-echelles__grp {
+    display: flex;
+  }
+  .nav-echelles__grp + .nav-echelles__grp::before {
+    content: "";
+    position: absolute;
+    left: calc(var(--space-lg) / -2);
+    top: 10px;
+    bottom: 10px;
+    border-left: 1px solid var(--border);
+  }
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .nav-echelles__tab { transition: none; }
+}
+</style>
diff --git a/components/NavTiroir.vue b/components/NavTiroir.vue
new file mode 100644
index 0000000..14ca19f
--- /dev/null
+++ b/components/NavTiroir.vue
@@ -0,0 +1,313 @@
+<!--
+  NavTiroir — B10-M3
+  Menu < 1280 px : tiroir pleine hauteur à droite, voile, Échap, focus piégé,
+  focus rendu à l'élément qui l'a ouvert. Les trois échelles dans l'ordre de la
+  barre (utils/echelles.ts), puis Manifeste, À propos, Signaler, et Soutenir.
+  Se ferme seul au changement de route et si la fenêtre passe à ≥ 1280 px.
+-->
+<template>
+  <Teleport to="body">
+    <Transition name="nav-tiroir">
+      <div v-if="open" class="nav-tiroir" @keydown="onKeydown">
+        <div class="nav-tiroir__voile" aria-hidden="true" @click="fermer" />
+        <div
+          ref="panneau"
+          class="nav-tiroir__panneau"
+          role="dialog"
+          aria-modal="true"
+          aria-labelledby="nav-tiroir-titre"
+        >
+          <div class="nav-tiroir__tete">
+            <h2 id="nav-tiroir-titre" class="nav-tiroir__titre">Menu</h2>
+            <button type="button" class="nav-tiroir__fermer" aria-label="Fermer le menu" @click="fermer">
+              <svg width="18" height="18" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2.5" stroke-linecap="round" aria-hidden="true">
+                <line x1="18" y1="6" x2="6" y2="18" /><line x1="6" y1="6" x2="18" y2="18" />
+              </svg>
+            </button>
+          </div>
+
+          <nav class="nav-tiroir__corps" aria-label="Échelles et pages">
+            <p class="nav-tiroir__cadre">{{ ECHELLES_CADRE_COURT }}</p>
+
+            <div v-for="id in ORDRE_ECHELLES" :key="id" class="nav-tiroir__grp">
+              <span :id="`nav-tiroir-echelle-${id}`" class="nav-tiroir__kick">
+                <span class="nav-tiroir__pastille">{{ id }}</span>{{ ECHELLES[id].titre }}
+              </span>
+              <ul class="nav-tiroir__liste" :aria-labelledby="`nav-tiroir-echelle-${id}`">
+                <li v-for="o in ECHELLES[id].onglets" :key="o.to">
+                  <NuxtLink
+                    :to="o.to"
+                    class="nav-tiroir__lien"
+                    :class="{ 'nav-tiroir__lien--actif': o.actif(route) }"
+                    :aria-current="o.actif(route) ? 'page' : undefined"
+                    @click="fermer"
+                  >{{ o.libelle }}</NuxtLink>
+                </li>
+              </ul>
+            </div>
+
+            <hr class="nav-tiroir__sep" />
+
+            <ul class="nav-tiroir__liste">
+              <li v-for="p in PAGES" :key="p.to">
+                <NuxtLink
+                  :to="p.to"
+                  class="nav-tiroir__second"
+                  :aria-current="route.path === p.to ? 'page' : undefined"
+                  @click="fermer"
+                >{{ p.libelle }}</NuxtLink>
+              </li>
+            </ul>
+
+            <a :href="SOUTENIR_URL" target="_blank" rel="noopener noreferrer" class="nav-tiroir__soutenir">Soutenir</a>
+          </nav>
+        </div>
+      </div>
+    </Transition>
+  </Teleport>
+</template>
+
+<script setup lang="ts">
+import { ECHELLES, ECHELLES_CADRE_COURT, ORDRE_ECHELLES } from '~/utils/echelles'
+import { SOUTENIR_URL } from '~/utils/liens'
+
+const props = defineProps<{ open: boolean }>()
+const emit = defineEmits<{ close: [] }>()
+
+const PAGES = [
+  { libelle: 'Manifeste', to: '/manifeste' },
+  { libelle: 'À propos', to: '/a-propos' },
+  { libelle: 'Signaler', to: '/signaler' },
+]
+
+const route = useRoute()
+const panneau = ref<HTMLElement | null>(null)
+let retourFocus: HTMLElement | null = null
+
+function fermer() {
+  emit('close')
+}
+
+function focusables(): HTMLElement[] {
+  if (!panneau.value) return []
+  return [...panneau.value.querySelectorAll<HTMLElement>('a[href], button:not([disabled])')]
+}
+
+function onKeydown(e: KeyboardEvent) {
+  if (e.key === 'Escape') {
+    e.preventDefault()
+    fermer()
+    return
+  }
+  if (e.key !== 'Tab') return
+  const els = focusables()
+  if (!els.length) return
+  const premier = els[0]
+  const dernier = els[els.length - 1]
+  if (e.shiftKey && document.activeElement === premier) {
+    e.preventDefault()
+    dernier.focus()
+  } else if (!e.shiftKey && document.activeElement === dernier) {
+    e.preventDefault()
+    premier.focus()
+  }
+}
+
+watch(() => props.open, async (ouvert) => {
+  if (ouvert) {
+    retourFocus = document.activeElement as HTMLElement | null
+    await nextTick()
+    focusables()[0]?.focus()
+  } else if (retourFocus) {
+    // Le bouton d'ouverture peut ne plus être visible (fenêtre élargie) : focus() est alors sans effet.
+    retourFocus.focus()
+    retourFocus = null
+  }
+})
+
+watch(() => route.fullPath, () => { if (props.open) fermer() })
+
+let mq: MediaQueryList | null = null
+function onLarge(e: MediaQueryListEvent) { if (e.matches && props.open) fermer() }
+onMounted(() => {
+  mq = window.matchMedia('(min-width: 1280px)')
+  mq.addEventListener('change', onLarge)
+})
+onBeforeUnmount(() => mq?.removeEventListener('change', onLarge))
+</script>
+
+<style scoped>
+.nav-tiroir {
+  position: fixed;
+  inset: 0;
+  z-index: 10000;
+}
+
+.nav-tiroir__voile {
+  position: absolute;
+  inset: 0;
+  background: rgba(var(--nav-primary-raw), 0.35);
+}
+
+.nav-tiroir__panneau {
+  position: absolute;
+  top: 0;
+  right: 0;
+  bottom: 0;
+  width: min(320px, 88vw);
+  display: flex;
+  flex-direction: column;
+  background: var(--surface);
+  color: var(--text);
+  box-shadow: var(--shadow-lg);
+}
+
+.nav-tiroir__tete {
+  display: flex;
+  align-items: center;
+  justify-content: space-between;
+  flex-shrink: 0;
+  padding: var(--space-xs) var(--space-sm) var(--space-xs) var(--space-md);
+  border-bottom: 1px solid var(--border);
+}
+
+.nav-tiroir__titre {
+  margin: 0;
+  font-size: var(--fs-sm);
+  font-weight: var(--fw-semibold);
+}
+
+.nav-tiroir__fermer {
+  display: grid;
+  place-items: center;
+  width: 44px;
+  height: 44px;
+  border: 0;
+  border-radius: var(--radius-md);
+  background: transparent;
+  color: var(--text);
+  cursor: pointer;
+}
+
+.nav-tiroir__corps {
+  flex: 1;
+  min-height: 0;
+  overflow-y: auto;
+  padding: var(--space-sm) var(--space-md) var(--space-lg);
+}
+
+.nav-tiroir__cadre {
+  margin: 0 0 var(--space-xs);
+  font-size: var(--fs-xs);
+  line-height: var(--lh-base);
+  color: color-mix(in srgb, var(--text) 78%, transparent);
+}
+
+.nav-tiroir__grp {
+  margin-top: var(--space-sm);
+}
+
+.nav-tiroir__kick {
+  display: block;
+  margin-bottom: var(--space-2xs);
+  font-size: 0.72rem;
+  font-weight: var(--fw-bold);
+  letter-spacing: 0.04em;
+  text-transform: uppercase;
+  color: color-mix(in srgb, var(--text) 78%, transparent);
+}
+
+.nav-tiroir__pastille {
+  display: inline-block;
+  margin-right: 6px;
+  padding: 0 5px;
+  border-radius: var(--radius-sm);
+  background: var(--accent);
+  color: var(--on-accent);
+}
+
+.nav-tiroir__liste {
+  margin: 0;
+  padding: 0;
+  list-style: none;
+}
+
+.nav-tiroir__lien,
+.nav-tiroir__second {
+  display: flex;
+  align-items: center;
+  min-height: 44px;
+  padding: 0 var(--space-xs);
+  border-radius: var(--radius-md);
+  text-decoration: none;
+}
+
+.nav-tiroir__lien {
+  font-size: var(--fs-base);
+  color: var(--text);
+}
+
+.nav-tiroir__lien--actif {
+  background: var(--bg-alt);
+  font-weight: var(--fw-semibold);
+}
+
+.nav-tiroir__second {
+  font-size: var(--fs-sm);
+  color: color-mix(in srgb, var(--text) 78%, transparent);
+}
+
+.nav-tiroir__lien:focus-visible,
+.nav-tiroir__second:focus-visible,
+.nav-tiroir__soutenir:focus-visible,
+.nav-tiroir__fermer:focus-visible {
+  outline: 2px solid var(--focus-ring);
+  outline-offset: 2px;
+}
+
+.nav-tiroir__sep {
+  margin: var(--space-sm) 0;
+  border: 0;
+  border-top: 1px solid var(--border);
+}
+
+.nav-tiroir__soutenir {
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  min-height: 44px;
+  margin-top: var(--space-sm);
+  border-radius: var(--radius-md);
+  background: var(--accent);
+  color: var(--on-accent);
+  font-size: var(--fs-sm);
+  font-weight: var(--fw-semibold);
+  text-decoration: none;
+}
+
+.nav-tiroir-enter-active,
+.nav-tiroir-leave-active {
+  transition: opacity var(--dur-base) var(--ease-out);
+}
+.nav-tiroir-enter-active .nav-tiroir__panneau,
+.nav-tiroir-leave-active .nav-tiroir__panneau {
+  transition: transform var(--dur-base) var(--ease-out);
+}
+.nav-tiroir-enter-from,
+.nav-tiroir-leave-to {
+  opacity: 0;
+}
+.nav-tiroir-enter-from .nav-tiroir__panneau,
+.nav-tiroir-leave-to .nav-tiroir__panneau {
+  transform: translateX(100%);
+}
+
+@media (prefers-reduced-motion: reduce) {
+  .nav-tiroir-enter-active,
+  .nav-tiroir-leave-active,
+  .nav-tiroir-enter-active .nav-tiroir__panneau,
+  .nav-tiroir-leave-active .nav-tiroir__panneau {
+    transition: none;
+  }
+}
+</style>
diff --git a/nuxt.config.ts b/nuxt.config.ts
index b9761e8..769f2ce 100644
--- a/nuxt.config.ts
+++ b/nuxt.config.ts
@@ -3,6 +3,7 @@ export default defineNuxtConfig({
 
   app: {
     head: {
+      htmlAttrs: { lang: 'fr' },
       link: [
         { rel: 'icon', type: 'image/svg+xml', href: '/favicon.svg' },
         { rel: 'icon', type: 'image/png', sizes: '32x32', href: '/favicon-32.png' },
diff --git a/utils/liens.ts b/utils/liens.ts
new file mode 100644
index 0000000..03ab44d
--- /dev/null
+++ b/utils/liens.ts
@@ -0,0 +1,2 @@
+/** Lien de don (Liberapay), partagé par la barre, le tiroir et À propos. */
+export const SOUTENIR_URL = 'https://liberapay.com/trans-former.fr/donate'