content: import React from 'react';
  import App from 'next/app';
  import Head from 'next/head';
  import { ThemeProvider } from '@material-ui/styles';
  import CssBaseline from '@material-ui/core/CssBaseline';
  import theme from '../src/theme';
  
  export default class MyApp extends App {
    componentDidMount() {
      // Remove the server-side injected CSS.
      const jssStyles = document.querySelector('#jss-server-side');
      if (jssStyles) {
        jssStyles.parentNode.removeChild(jssStyles);
      }
    }
  
    render() {
      const { Component, pageProps } = this.props;
  
      return (
        <React.Fragment>
          <Head>
            <title>My page</title>
          </Head>
          <ThemeProvider theme={theme}>
            {/* CssBaseline kickstart an elegant, consistent, and simple baseline to build upon. */}
            <CssBaseline />
            <Component {...pageProps} />
          </ThemeProvider>
        </React.Fragment>
      );
    }
  }
  