import * as React from 'react'; import { CssVarsProvider, extendTheme, useColorScheme } from '@mui/material/styles'; import AppBar from '@mui/material/AppBar'; import Box from '@mui/material/Box'; import Paper from '@mui/material/Paper'; import Toolbar from '@mui/material/Toolbar'; function LightMode() { const { setMode } = useColorScheme(); React.useEffect(() => { setMode('light'); }, [setMode]); return null; } const theme = extendTheme({ defaultColorScheme: 'dark', colorSchemeSelector: '.mode-%s' }); export default function MaterialUIDefaultDark() { return ( div': { placeSelf: 'center', }, }} > The color should be secondary. You should not see overlay. ); }