My page

import React from 'react'; import PropTypes from 'prop-types'; import Head from 'next/head'; import { ThemeProvider } from '@material-ui/core/styles'; import CssBaseline from '@material-ui/core/CssBaseline'; import theme from '../src/theme'; import '../styles/globals.css' export default function MyApp(props) { const { Component, pageProps } = props; React.useEffect(() => { // Remove the server-side injected CSS. const jssStyles = document.querySelector('#jss-server-side'); if (jssStyles) { jssStyles.parentElement.removeChild(jssStyles); } }, []); return ( My page {/* CssBaseline kickstart an elegant, consistent, and simple baseline to build upon. */} ); } MyApp.propTypes = { Component: PropTypes.elementType.isRequired, pageProps: PropTypes.object.isRequired, };