import { styled, createTheme, ThemeProvider } from '@mui/system'; const customTheme = createTheme({ palette: { primary: { main: '#1976d2', contrastText: 'white', }, }, }); const MyThemeComponent = styled('div')(({ theme }) => ({ color: theme.palette.primary.contrastText, backgroundColor: theme.palette.primary.main, padding: theme.spacing(1), borderRadius: theme.shape.borderRadius, })); export default function ThemeUsage() { return ( Styled div with theme ); }