diff --git a/frontend-prep/src/context/ThemeContext.tsx b/frontend-prep/src/context/ThemeContext.tsx
index ca50e7b4..1ed0e76a 100644
--- a/frontend-prep/src/context/ThemeContext.tsx
+++ b/frontend-prep/src/context/ThemeContext.tsx
@@ -1,4 +1,4 @@
-import { createContext, useContext, useEffect, useState } from "react";
+import { createContext, useContext, useEffect, useRef, useState } from "react";
 import type { ReactNode } from "react";
 import { getPublicSettings } from "../api/api";
 
@@ -22,12 +22,43 @@ function hexToRgba(hex: string, alpha: number): string {
     return `rgba(${r}, ${g}, ${b}, ${alpha})`;
 }
 
-function applyClientColors(s: { client_color_primary: string; client_color_secondary: string; client_color_success: string; client_color_danger: string; client_color_warning: string }) {
+// Mélange une couleur de teinte sur un fond noir
+function tintOnBlack(tintHex: string, ratio: number): string {
+    const h = tintHex.replace("#", "");
+    const r = Math.min(255, Math.round(parseInt(h.substring(0, 2), 16) * ratio));
+    const g = Math.min(255, Math.round(parseInt(h.substring(2, 4), 16) * ratio));
+    const b = Math.min(255, Math.round(parseInt(h.substring(4, 6), 16) * ratio));
+    return `#${r.toString(16).padStart(2, "0")}${g.toString(16).padStart(2, "0")}${b.toString(16).padStart(2, "0")}`;
+}
+
+type ColorSettings = {
+    client_color_primary: string;
+    client_color_secondary: string;
+    client_color_success: string;
+    client_color_danger: string;
+    client_color_warning: string;
+};
+
+function applyClientColors(s: ColorSettings) {
     const root = document.documentElement;
+    const isDark = root.getAttribute("data-theme") !== "light";
+
     if (s.client_color_primary) {
-        root.style.setProperty("--primary", s.client_color_primary);
-        root.style.setProperty("--primary-soft", hexToRgba(s.client_color_primary, 0.12));
-        root.style.setProperty("--primary-glow", hexToRgba(s.client_color_primary, 0.25));
+        const p = s.client_color_primary;
+        root.style.setProperty("--primary", p);
+        root.style.setProperty("--primary-soft", hexToRgba(p, 0.12));
+        root.style.setProperty("--primary-glow", hexToRgba(p, 0.25));
+        if (isDark) {
+            // Teinter le fond avec la couleur primaire
+            root.style.setProperty("--bg",       tintOnBlack(p, 0.20));
+            root.style.setProperty("--surface",   tintOnBlack(p, 0.25));
+            root.style.setProperty("--surface-2", tintOnBlack(p, 0.32));
+        } else {
+            // En mode clair, réinitialiser pour laisser le CSS prendre le contrôle
+            root.style.removeProperty("--bg");
+            root.style.removeProperty("--surface");
+            root.style.removeProperty("--surface-2");
+        }
     }
     if (s.client_color_secondary) {
         root.style.setProperty("--cyan", s.client_color_secondary);
@@ -44,16 +75,25 @@ export function ThemeProvider({ children }: { children: ReactNode }) {
         if (stored === "light" || stored === "dark") return stored;
         return "dark";
     });
+    const lastSettings = useRef<ColorSettings | null>(null);
 
     useEffect(() => {
         document.documentElement.setAttribute("data-theme", theme);
         localStorage.setItem("theme", theme);
     }, [theme]);
 
+    // Re-appliquer les couleurs quand le thème change (le tinting bg dépend du mode)
+    useEffect(() => {
+        if (lastSettings.current) {
+            applyClientColors(lastSettings.current);
+        }
+    }, [theme]);
+
     useEffect(() => {
         const fetchColors = async () => {
             try {
                 const settings = await getPublicSettings();
+                lastSettings.current = settings;
                 applyClientColors(settings);
             } catch { /* ignore */ }
         };