text: import React from "react";
  import Document, { Html, Head, Main, NextScript } from "next/document";
  import { ServerStyleSheets } from "@material-ui/core/styles";
  import theme from "../src/theme";
  
  export default class MyDocument extends Document {
    render() {
      return (
        <Html lang="en">
          <Head>
            {/* PWA primary color */}
  
            <meta name="theme-color" content={theme.palette.primary.main} />
            <link
              rel="stylesheet"
              href="https://fonts.googleapis.com/css?family=Roboto:300,400,500,700&display=swap"
            />
            <link
              href="https://fonts.googleapis.com/css?family=Roboto+Condensed:300,400,700|Roboto+Mono:100,400,700|Roboto:100,400,700&display=swap"
              rel="stylesheet"
            />
            <link
              rel="icon"
              href="https://emojipedia-us.s3.dualstack.us-west-1.amazonaws.com/thumbs/120/google/241/thinking-face_1f914.png"
            />
          </Head>
          <body>
            <Main />
            <NextScript />
          </body>
        </Html>
      );
    }
  }
  
  // `getInitialProps` belongs to `_document` (instead of `_app`),
  // it's compatible with server-side generation (SSG).
  MyDocument.getInitialProps = async (ctx) => {
    // Resolution order
    //
    // On the server:
    // 1. app.getInitialProps
    // 2. page.getInitialProps
    // 3. document.getInitialProps
    // 4. app.render
    // 5. page.render
    // 6. document.render
    //
    // On the server with error:
    // 1. document.getInitialProps
    // 2. app.render
    // 3. page.render
    // 4. document.render
    //
    // On the client
    // 1. app.getInitialProps
    // 2. page.getInitialProps
    // 3. app.render
    // 4. page.render
  
    // Render app and page and get the context of the page with collected side effects.
    const sheets = new ServerStyleSheets();
    const originalRenderPage = ctx.renderPage;
  
    ctx.renderPage = () =>
      originalRenderPage({
        enhanceApp: (App) => (props) => sheets.collect(<App {...props} />),
      });
  
    const initialProps = await Document.getInitialProps(ctx);
  
    return {
      ...initialProps,
      // Styles fragment is rendered after the app and page rendering finish.
      styles: [
        ...React.Children.toArray(initialProps.styles),
        sheets.getStyleElement(),
      ],
    };
  };
  