How to use CSS-in-JS libraries — Next.js

{/* The content of this doc is shared between the app and pages router. You can use the <PagesOnly>Content</PagesOnly> component to add content that is specific to the Pages Router. Any shared content should not be wrapped in a component. */}

Warning: Using CSS-in-JS with newer React features like Server Components and Streaming requires library authors to support the latest version of React, including concurrent rendering.

The following libraries are supported in Client Components in the app directory (alphabetical):

The following are currently working on support:

emotion

Good to know: We're testing out different CSS-in-JS libraries and we'll be adding more examples for libraries that support React 18 features and/or the app directory.

Configuring CSS-in-JS in `app`

Configuring CSS-in-JS is a three-step opt-in process that involves:

A style registry to collect all CSS rules in a render.
The new useServerInsertedHTML hook to inject rules before any content that might use them.
A Client Component that wraps your app with the style registry during initial server-side rendering.

`styled-jsx`

Using styled-jsx in Client Components requires using v5.1.0. First, create a new registry:

'use client'

import React, { useState } from 'react'
import { useServerInsertedHTML } from 'next/navigation'
import { StyleRegistry, createStyleRegistry } from 'styled-jsx'

export default function StyledJsxRegistry({
  children,
}: {
  children: React.ReactNode
}) {
  // Only create stylesheet once with lazy initial state
  // x-ref: https://reactjs.org/docs/hooks-reference.html#lazy-initial-state
  const [jsxStyleRegistry] = useState(() => createStyleRegistry())

  useServerInsertedHTML(() => {
    const styles = jsxStyleRegistry.styles()
    jsxStyleRegistry.flush()
    return <>{styles}</>
  })

  return <StyleRegistry registry={jsxStyleRegistry}>{children}</StyleRegistry>
}

'use client'

import React, { useState } from 'react'
import { useServerInsertedHTML } from 'next/navigation'
import { StyleRegistry, createStyleRegistry } from 'styled-jsx'

export default function StyledJsxRegistry({ children }) {
  // Only create stylesheet once with lazy initial state
  // x-ref: https://reactjs.org/docs/hooks-reference.html#lazy-initial-state
  const [jsxStyleRegistry] = useState(() => createStyleRegistry())

  useServerInsertedHTML(() => {
    const styles = jsxStyleRegistry.styles()
    jsxStyleRegistry.flush()
    return <>{styles}</>
  })

  return <StyleRegistry registry={jsxStyleRegistry}>{children}</StyleRegistry>
}

Then, wrap your root layout with the registry:

import StyledJsxRegistry from './registry'

export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html>
      <body>
        <StyledJsxRegistry>{children}</StyledJsxRegistry>
      </body>
    </html>
  )
}

import StyledJsxRegistry from './registry'

export default function RootLayout({ children }) {
  return (
    <html>
      <body>
        <StyledJsxRegistry>{children}</StyledJsxRegistry>
      </body>
    </html>
  )
}

View an example here.

Styled Components

Below is an example of how to configure styled-components@6 or newer:

First, enable styled-components in next.config.js.

module.exports = {
  compiler: {
    styledComponents: true,
  },
}

Then, use the styled-components API to create a global registry component to collect all CSS style rules generated during a render, and a function to return those rules. Then use the useServerInsertedHTML hook to inject the styles collected in the registry into the <head> HTML tag in the root layout.

'use client'

import React, { useState } from 'react'
import { useServerInsertedHTML } from 'next/navigation'
import { ServerStyleSheet, StyleSheetManager } from 'styled-components'

export default function StyledComponentsRegistry({
  children,
}: {
  children: React.ReactNode
}) {
  // Only create stylesheet once with lazy initial state
  // x-ref: https://reactjs.org/docs/hooks-reference.html#lazy-initial-state
  const [styledComponentsStyleSheet] = useState(() => new ServerStyleSheet())

  useServerInsertedHTML(() => {
    const styles = styledComponentsStyleSheet.getStyleElement()
    styledComponentsStyleSheet.instance.clearTag()
    return <>{styles}</>
  })

  if (typeof window !== 'undefined') return <>{children}</>

  return (
    <StyleSheetManager sheet={styledComponentsStyleSheet.instance}>
      {children}
    </StyleSheetManager>
  )
}

'use client'

import React, { useState } from 'react'
import { useServerInsertedHTML } from 'next/navigation'
import { ServerStyleSheet, StyleSheetManager } from 'styled-components'

export default function StyledComponentsRegistry({ children }) {
  // Only create stylesheet once with lazy initial state
  // x-ref: https://reactjs.org/docs/hooks-reference.html#lazy-initial-state
  const [styledComponentsStyleSheet] = useState(() => new ServerStyleSheet())

  useServerInsertedHTML(() => {
    const styles = styledComponentsStyleSheet.getStyleElement()
    styledComponentsStyleSheet.instance.clearTag()
    return <>{styles}</>
  })

  if (typeof window !== 'undefined') return <>{children}</>

  return (
    <StyleSheetManager sheet={styledComponentsStyleSheet.instance}>
      {children}
    </StyleSheetManager>
  )
}

Wrap the children of the root layout with the style registry component:

import StyledComponentsRegistry from './lib/registry'

export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html>
      <body>
        <StyledComponentsRegistry>{children}</StyledComponentsRegistry>
      </body>
    </html>
  )
}

import StyledComponentsRegistry from './lib/registry'

export default function RootLayout({ children }) {
  return (
    <html>
      <body>
        <StyledComponentsRegistry>{children}</StyledComponentsRegistry>
      </body>
    </html>
  )
}

View an example here.

Good to know:

During server rendering, styles will be extracted to a global registry and flushed to the <head> of your HTML. This ensures the style rules are placed before any content that might use them. In the future, we may use an upcoming React feature to determine where to inject the styles.

During streaming, styles from each chunk will be collected and appended to existing styles. After client-side hydration is complete, styled-components will take over as usual and inject any further dynamic styles.

We specifically use a Client Component at the top level of the tree for the style registry because it's more efficient to extract CSS rules this way. It avoids re-generating styles on subsequent server renders, and prevents them from being sent in the Server Component payload.

For advanced use cases where you need to configure individual properties of styled-components compilation, you can read our Next.js styled-components API reference to learn more.

It's possible to use any existing CSS-in-JS solution. The simplest one is inline styles:

function HiThere() {
  return <p style={{ color: 'red' }}>hi there</p>
}

export default HiThere

We bundle styled-jsx to provide support for isolated scoped CSS. The aim is to support "shadow CSS" similar to Web Components, which unfortunately do not support server-rendering and are JS-only.

See the above examples for other popular CSS-in-JS solutions (like Styled Components).

A component using styled-jsx looks like this:

function HelloWorld() {
  return (
    <div>
      Hello world
      <p>scoped!</p>
      <style jsx>{`
        p {
          color: blue;
        }
        div {
          background: red;
        }
        @media (max-width: 600px) {
          div {
            background: blue;
          }
        }
      `}</style>
      <style global jsx>{`
        body {
          background: black;
        }
      `}</style>
    </div>
  )
}

export default HelloWorld

Please see the styled-jsx documentation for more examples.

Disabling JavaScript

Yes, if you disable JavaScript the CSS will still be loaded in the production build (next start). During development, we require JavaScript to be enabled to provide the best developer experience with Fast Refresh.

Source: docs/01-app/02-guides/css-in-js.mdx

Configuring CSS-in-JS in app

styled-jsx

Styled Components

Disabling JavaScript

Configuring CSS-in-JS in `app`

`styled-jsx`