react-test/docs/data/material/customization/theming/ThemeNesting.tsx

import { createTheme, ThemeProvider } from '@mui/material/styles';
import Checkbox from '@mui/material/Checkbox';
import { green, orange } from '@mui/material/colors';

const outerTheme = createTheme({
  palette: {
    primary: {
      main: orange[500],
    },
  },
});

const innerTheme = createTheme({
  palette: {
    primary: {
      main: green[500],
    },
  },
});

export default function ThemeNesting() {
  return (
    <ThemeProvider theme={outerTheme}>
      <Checkbox defaultChecked />
      <ThemeProvider theme={innerTheme}>
        <Checkbox defaultChecked />
      </ThemeProvider>
    </ThemeProvider>
  );
}