import Document from "next/document" ; import { ServerStyleSheet } from "styled-components" ; export default class MyDocument extends Document { static async getInitialProps ( ctx ) { const sheet = new ServerStyleSheet ( ) ; const originalRenderPage = ctx . renderPage ; try { ctx . renderPage = ( ) => originalRenderPage ( { enhanceApp : App => props => sheet . collectStyles ( < App { ... props } / > ) } ) ; const initialProps = await Document . getInitialProps ( ctx ) ; return { ... initialProps , styles : ( < > { initialProps . styles } { sheet . getStyleElement ( ) } < />) } ; } finally { sheet . seal ( ) ; } } }