diff --git a/README.md b/README.md
index ecf0d19..2f840be 100644
--- a/README.md
+++ b/README.md
@@ -87,6 +87,13 @@ pinia@^3.0.2             # State management
 typescript@^5.8.2        # Typage statique
 ```
 
+Le frontend étend le layer partagé **`../../yvv-nuxt-base`** (`extends` dans
+`nuxt.config.ts`) : le composable `useMood` y centralise l'application DOM des
+palettes (variables CSS + classe `.palette-dark`), la persistance localStorage et
+le light/dark. Les palettes propres à SejeteralO (6 ambiances + variables SVG des
+graphiques) sont définies côté projet dans `app/composables/usePalette.ts`, qui
+délègue à `useMood` et synchronise l'état partagé `useState('theme-dark')`.
+
 ## Base de donnees
 
 **SQLite** en dev/production legere, configurable via `DATABASE_URL`.
diff --git a/frontend/app/components/DisplaySettings.vue b/frontend/app/components/DisplaySettings.vue
index 2cae298..b4055cc 100644
--- a/frontend/app/components/DisplaySettings.vue
+++ b/frontend/app/components/DisplaySettings.vue
@@ -61,8 +61,8 @@
 </template>
 
 <script setup lang="ts">
-// Global shared dark mode state (accessible from any component via useState)
-const isDark = useState('theme-dark', () => false)
+// Palette : identité + application DOM/persistance/dark déléguées à useMood.
+const { paletteList, currentPalette, setPalette, initPalette } = usePalette()
 
 const selectorRef = ref<HTMLElement>()
 const isOpen = ref(false)
@@ -101,92 +101,6 @@ function setDensity(d: string) {
   }
 }
 
-// ── Palette definitions ──
-interface Palette {
-  name: string; label: string; dark: boolean
-  primary: string; accent: string
-  bg: string; surface: string; text: string; textMuted: string; border: string
-  // SVG-specific
-  svgPlotBg: string; svgGrid: string; svgLegendBg: string; svgText: string; svgTextLight: string
-}
-
-const paletteList: Palette[] = [
-  // ── Light palettes ──
-  {
-    name: 'eau', label: 'Eau', dark: false,
-    primary: '#2563eb', accent: '#059669',
-    bg: '#f8fafc', surface: '#ffffff', text: '#1e293b', textMuted: '#64748b', border: '#e2e8f0',
-    svgPlotBg: '#f8fafc', svgGrid: '#e2e8f0', svgLegendBg: 'white', svgText: '#334155', svgTextLight: '#64748b',
-  },
-  {
-    name: 'terre', label: 'Terre', dark: false,
-    primary: '#92400e', accent: '#d97706',
-    bg: '#fefbf6', surface: '#ffffff', text: '#1c1917', textMuted: '#78716c', border: '#e7e5e4',
-    svgPlotBg: '#faf8f5', svgGrid: '#e7e5e4', svgLegendBg: 'white', svgText: '#44403c', svgTextLight: '#78716c',
-  },
-  {
-    name: 'foret', label: 'Foret', dark: false,
-    primary: '#166534', accent: '#65a30d',
-    bg: '#f7fdf9', surface: '#ffffff', text: '#14532d', textMuted: '#6b7c6e', border: '#d1e7d6',
-    svgPlotBg: '#f5fbf7', svgGrid: '#d1e7d6', svgLegendBg: 'white', svgText: '#2d4a35', svgTextLight: '#6b7c6e',
-  },
-  {
-    name: 'ardoise', label: 'Ardoise', dark: false,
-    primary: '#475569', accent: '#64748b',
-    bg: '#f8fafc', surface: '#ffffff', text: '#1e293b', textMuted: '#64748b', border: '#e2e8f0',
-    svgPlotBg: '#f8fafc', svgGrid: '#e2e8f0', svgLegendBg: 'white', svgText: '#334155', svgTextLight: '#64748b',
-  },
-  // ── Dark palettes ──
-  {
-    name: 'nuit', label: 'Nuit', dark: true,
-    primary: '#60a5fa', accent: '#34d399',
-    bg: '#0f172a', surface: '#1e293b', text: '#f1f5f9', textMuted: '#94a3b8', border: '#334155',
-    svgPlotBg: '#1e293b', svgGrid: '#334155', svgLegendBg: '#1e293b', svgText: '#cbd5e1', svgTextLight: '#94a3b8',
-  },
-  {
-    name: 'ocean', label: 'Ocean', dark: true,
-    primary: '#38bdf8', accent: '#2dd4bf',
-    bg: '#0c1222', surface: '#162032', text: '#e2e8f0', textMuted: '#7dd3fc', border: '#1e3a5f',
-    svgPlotBg: '#162032', svgGrid: '#1e3a5f', svgLegendBg: '#162032', svgText: '#bae6fd', svgTextLight: '#7dd3fc',
-  },
-]
-const currentPalette = ref('eau')
-
-function setPalette(name: string) {
-  currentPalette.value = name
-  const p = paletteList.find(x => x.name === name)
-  if (!p || !import.meta.client) return
-  localStorage.setItem('sej-palette', name)
-
-  const root = document.documentElement
-  const s = root.style
-  s.setProperty('--color-primary', p.primary)
-  s.setProperty('--color-primary-dark', darken(p.primary))
-  s.setProperty('--color-secondary', p.accent)
-  s.setProperty('--color-bg', p.bg)
-  s.setProperty('--color-surface', p.surface)
-  s.setProperty('--color-text', p.text)
-  s.setProperty('--color-text-muted', p.textMuted)
-  s.setProperty('--color-border', p.border)
-  // SVG theme vars
-  s.setProperty('--svg-plot-bg', p.svgPlotBg)
-  s.setProperty('--svg-grid', p.svgGrid)
-  s.setProperty('--svg-legend-bg', p.svgLegendBg)
-  s.setProperty('--svg-text', p.svgText)
-  s.setProperty('--svg-text-light', p.svgTextLight)
-
-  root.classList.toggle('palette-dark', p.dark)
-  isDark.value = p.dark
-}
-
-function darken(hex: string): string {
-  const r = parseInt(hex.slice(1, 3), 16)
-  const g = parseInt(hex.slice(3, 5), 16)
-  const b = parseInt(hex.slice(5, 7), 16)
-  const f = 0.82
-  return `#${Math.round(r * f).toString(16).padStart(2, '0')}${Math.round(g * f).toString(16).padStart(2, '0')}${Math.round(b * f).toString(16).padStart(2, '0')}`
-}
-
 // ── Init from localStorage ──
 onMounted(() => {
   if (!import.meta.client) return
@@ -194,8 +108,8 @@ onMounted(() => {
   if (savedFont) setFontSize(savedFont)
   const savedDensity = localStorage.getItem('sej-density')
   if (savedDensity) setDensity(savedDensity)
-  const savedPalette = localStorage.getItem('sej-palette')
-  if (savedPalette) setPalette(savedPalette)
+  // Palette : restauration + application déléguées au composable partagé.
+  initPalette()
 })
 
 // ── Click outside to close ──
diff --git a/frontend/app/composables/usePalette.ts b/frontend/app/composables/usePalette.ts
new file mode 100644
index 0000000..6a26a81
--- /dev/null
+++ b/frontend/app/composables/usePalette.ts
@@ -0,0 +1,131 @@
+import type { MoodDef } from '#imports'
+
+/**
+ * Palettes SejeteralO — identité couleur du projet.
+ * L'application DOM (variables CSS + classe .palette-dark), la persistance et
+ * le light/dark sont délégués au mécanisme partagé `useMood` (@yvv/nuxt-base).
+ * Chaque palette injecte AUSSI ses variables SVG (thème des graphiques) et un
+ * `--color-primary-dark` dérivé — d'où le précalcul en `vars`.
+ */
+export interface Palette {
+  name: string
+  label: string
+  dark: boolean
+  primary: string
+  accent: string
+  bg: string
+  surface: string
+  text: string
+  textMuted: string
+  border: string
+  // SVG-specific (thème des graphiques)
+  svgPlotBg: string
+  svgGrid: string
+  svgLegendBg: string
+  svgText: string
+  svgTextLight: string
+}
+
+export const paletteList: Palette[] = [
+  // ── Light palettes ──
+  {
+    name: 'eau', label: 'Eau', dark: false,
+    primary: '#2563eb', accent: '#059669',
+    bg: '#f8fafc', surface: '#ffffff', text: '#1e293b', textMuted: '#64748b', border: '#e2e8f0',
+    svgPlotBg: '#f8fafc', svgGrid: '#e2e8f0', svgLegendBg: 'white', svgText: '#334155', svgTextLight: '#64748b',
+  },
+  {
+    name: 'terre', label: 'Terre', dark: false,
+    primary: '#92400e', accent: '#d97706',
+    bg: '#fefbf6', surface: '#ffffff', text: '#1c1917', textMuted: '#78716c', border: '#e7e5e4',
+    svgPlotBg: '#faf8f5', svgGrid: '#e7e5e4', svgLegendBg: 'white', svgText: '#44403c', svgTextLight: '#78716c',
+  },
+  {
+    name: 'foret', label: 'Foret', dark: false,
+    primary: '#166534', accent: '#65a30d',
+    bg: '#f7fdf9', surface: '#ffffff', text: '#14532d', textMuted: '#6b7c6e', border: '#d1e7d6',
+    svgPlotBg: '#f5fbf7', svgGrid: '#d1e7d6', svgLegendBg: 'white', svgText: '#2d4a35', svgTextLight: '#6b7c6e',
+  },
+  {
+    name: 'ardoise', label: 'Ardoise', dark: false,
+    primary: '#475569', accent: '#64748b',
+    bg: '#f8fafc', surface: '#ffffff', text: '#1e293b', textMuted: '#64748b', border: '#e2e8f0',
+    svgPlotBg: '#f8fafc', svgGrid: '#e2e8f0', svgLegendBg: 'white', svgText: '#334155', svgTextLight: '#64748b',
+  },
+  // ── Dark palettes ──
+  {
+    name: 'nuit', label: 'Nuit', dark: true,
+    primary: '#60a5fa', accent: '#34d399',
+    bg: '#0f172a', surface: '#1e293b', text: '#f1f5f9', textMuted: '#94a3b8', border: '#334155',
+    svgPlotBg: '#1e293b', svgGrid: '#334155', svgLegendBg: '#1e293b', svgText: '#cbd5e1', svgTextLight: '#94a3b8',
+  },
+  {
+    name: 'ocean', label: 'Ocean', dark: true,
+    primary: '#38bdf8', accent: '#2dd4bf',
+    bg: '#0c1222', surface: '#162032', text: '#e2e8f0', textMuted: '#7dd3fc', border: '#1e3a5f',
+    svgPlotBg: '#162032', svgGrid: '#1e3a5f', svgLegendBg: '#162032', svgText: '#bae6fd', svgTextLight: '#7dd3fc',
+  },
+]
+
+/** Assombrit une couleur hex (facteur 0.82) — variante `--color-primary-dark`. */
+function darken(hex: string): string {
+  const r = parseInt(hex.slice(1, 3), 16)
+  const g = parseInt(hex.slice(3, 5), 16)
+  const b = parseInt(hex.slice(5, 7), 16)
+  const f = 0.82
+  return `#${Math.round(r * f).toString(16).padStart(2, '0')}${Math.round(g * f).toString(16).padStart(2, '0')}${Math.round(b * f).toString(16).padStart(2, '0')}`
+}
+
+const paletteMoods: MoodDef[] = paletteList.map(p => ({
+  id: p.name,
+  label: p.label,
+  isDark: p.dark,
+  vars: {
+    '--color-primary': p.primary,
+    '--color-primary-dark': darken(p.primary),
+    '--color-secondary': p.accent,
+    '--color-bg': p.bg,
+    '--color-surface': p.surface,
+    '--color-text': p.text,
+    '--color-text-muted': p.textMuted,
+    '--color-border': p.border,
+    // Thème SVG (graphiques)
+    '--svg-plot-bg': p.svgPlotBg,
+    '--svg-grid': p.svgGrid,
+    '--svg-legend-bg': p.svgLegendBg,
+    '--svg-text': p.svgText,
+    '--svg-text-light': p.svgTextLight,
+  },
+}))
+
+export function usePalette() {
+  const { currentMood, setMood, initMood } = useMood(paletteMoods, {
+    storageKey: 'sej-palette',
+    defaultId: 'eau',
+    syncColorMode: false, // pas de @nuxtjs/color-mode
+    lightDarkClasses: false, // le CSS ne stylise que .palette-dark
+    darkClass: 'palette-dark',
+  })
+
+  // État dark partagé, lu par la page graphiques (commune/[slug]) pour le thème SVG.
+  const isDark = useState('theme-dark', () => false)
+
+  function syncDark(id: string) {
+    const m = paletteMoods.find(x => x.id === id)
+    if (m) isDark.value = m.isDark
+  }
+
+  const currentPalette = computed(() => currentMood.value || 'eau')
+
+  function setPalette(name: string) {
+    setMood(name)
+    syncDark(name)
+  }
+
+  function initPalette() {
+    initMood()
+    syncDark(currentMood.value || 'eau')
+  }
+
+  return { paletteList, currentPalette, setPalette, initPalette, isDark }
+}
diff --git a/frontend/nuxt.config.ts b/frontend/nuxt.config.ts
index 5d5adcc..653bad4 100644
--- a/frontend/nuxt.config.ts
+++ b/frontend/nuxt.config.ts
@@ -1,4 +1,6 @@
 export default defineNuxtConfig({
+  extends: ['../../yvv-nuxt-base'],
+
   compatibilityDate: '2025-01-01',
   future: { compatibilityVersion: 4 },