How to use CSS in your application

Next.js provides several ways to use CSS in your application, including:

CSS Modules

CSS Modules locally scope CSS by generating unique class names. This allows you to use the same class in different files without worrying about naming collisions.

To start using CSS Modules, create a new file with the extension .module.css and import it into any component inside the app directory:

app/blog/styles.module.css

.blog {
  padding: 24px;
}

app/blog/page.tsx

import styles from './blog.module.css'
 
export default function Page() {
  return <main className={styles.blog}></main>
}

Global CSS

You can use global CSS to apply styles across your application.

Create a app/global.css file and import it in the root layout to apply the styles to every route in your application:

app/global.css

body {
  padding: 20px 20px 60px;
  max-width: 680px;
  margin: 0 auto;
}

app/layout.tsx

// These styles apply to every route in the application
import './global.css'
 
export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html lang="en">
      <body>{children}</body>
    </html>
  )
}

Good to know: Global styles can be imported into any layout, page, or component inside the app directory. However, since Next.js uses React's built-in support for stylesheets to integrate with Suspense, this currently does not remove stylesheets as you navigate between routes which can lead to conflicts. We recommend using global styles for truly global CSS, and CSS Modules for scoped CSS.

External stylesheets

Stylesheets published by external packages can be imported anywhere in the app directory, including colocated components:

app/layout.tsx

import 'bootstrap/dist/css/bootstrap.css'
 
export default function RootLayout({
  children,
}: {
  children: React.ReactNode
}) {
  return (
    <html lang="en">
      <body className="container">{children}</body>
    </html>
  )
}

Good to know: In React 19, <link rel="stylesheet" href="..." /> can also be used. See the React link documentationfor more information.

Ordering and Merging

Next.js optimizes CSS during production builds by automatically chunking (merging) stylesheets. The order of your CSS depends on the order you import styles in your code.

For example, base-button.module.css will be ordered before page.module.css since <BaseButton> is imported before page.module.css:

page.ts

import { BaseButton } from './base-button'
import styles from './page.module.css'
 
export default function Page() {
  return <BaseButton className={styles.primary} />
}

base-button.tsx

import styles from './base-button.module.css'
 
export function BaseButton() {
  return <button className={styles.primary} />
}

Recommendations

To keep CSS ordering predictable:

Try to contain CSS imports to a single JavaScript or TypeScript entry file
Import global styles and Tailwind stylesheets in the root of your application.
Use CSS Modules instead of global styles for nested components.
Use a consistent naming convention for your CSS modules. For example, using <name>.module.css over <name>.tsx.
Extract shared styles into shared components to avoid duplicate imports.
Turn off linters or formatters that auto-sort imports like ESLint’s sort-imports.
You can use the cssChunking option in next.config.js to control how CSS is chunked.

Development vs Production

In development (next dev), CSS updates apply instantly with Fast Refresh.
In production (next build), all CSS files are automatically concatenated into many minified and code-split .css files, ensuring the minimal amount of CSS is loaded for a route.
CSS still loads with JavaScript disabled in production, but JavaScript is required in development for Fast Refresh.
CSS ordering can behave differently in development, always ensure to check the build (next build) to verify the final CSS order.

How to use CSS in your application

CSS Modules

Global CSS

External stylesheets

Ordering and Merging

Recommendations

Development vs Production

Next Steps

Tailwind CSS

Sass

CSS-in-JS