diff --git a/src/theme/theme.ts b/src/theme/theme.ts
index 71a42e9b..353dd1a7 100644
--- a/src/theme/theme.ts
+++ b/src/theme/theme.ts
@@ -7,14 +7,11 @@ export const drawerWidth = 240;
 
 export const createCustomTheme = (mode: PaletteMode, brandPalette?: Interactiveness) => {
   const basePalette = mode == 'light' ? lightModePalette : darkModePalette;
-  const themePalette = brandPalette
-    ? Object.assign({}, basePalette, {
-        background: {
-          brand: brandPalette
-        }
-      })
-    : basePalette;
+  const themePalette = structuredClone(basePalette);
 
+  if (brandPalette && themePalette.background) {
+    themePalette.background.brand = brandPalette;
+  }
   return createTheme({
     palette: {
       mode,