# Adding a Global Stylesheet

To add a stylesheet to your application, import the CSS file within `pages/_app.js`.

For example, consider the following stylesheet named `styles.css`:

```css
body {
  font-family: 'SF Pro Text', 'SF Pro Icons', 'Helvetica Neue', 'Helvetica',
    'Arial', sans-serif;
  padding: 20px 20px 60px;
  max-width: 680px;
  margin: 0 auto;
}
```

&#x20;Create a `pages/_app.js` file if not already present. Then, [`import`](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Statements/import) the `styles.css` file.

```javascript
import '../styles.css'

// This default export is required in a new `pages/_app.js` file.
export default function MyApp({ Component, pageProps }) {
  return <Component {...pageProps} />
}
```

These styles (`styles.css`) will apply to all pages and components in your application. Due to the global nature of stylesheets, and to avoid conflicts, you may **only import them inside** [**`pages/_app.js`**](https://nextjs.org/docs/advanced-features/custom-app).

In development, expressing stylesheets this way allows your styles to be hot reloaded as you edit them—meaning you can keep application state.

In production, all CSS files will be automatically concatenated into a single minified `.css` file.

### Adding Component-Level CSS

Next.js supports CSS Modules using the `[name].module.css` file naming convention.

CSS Modules locally scope CSS by automatically creating a unique class name. This allows you to use the same CSS class name in different files without worrying about collisions.

This behavior makes CSS Modules the ideal way to include component-level CSS. CSS Module files **can be imported anywhere in your application**.

For example, consider a reusable `Button` component in the `components/` folder:

First, create `components/Button.module.css` with the following content:

```css
/*
You do not need to worry about .error {} colliding with any other `.css` or
`.module.css` files!
*/
.error {
  color: white;
  background-color: red;
}
```

&#x20;Then, create `components/Button.js`, importing and using the above CSS file:

```javascript
import styles from './Button.module.css'

export function Button() {
  return (
    <button
      type="button"
      className={styles.error}
    >
      Destroy
    </button>
  )
}
```

CSS Modules are an *optional feature* and are **only enabled for files with the `.module.css` extension**. Regular `<link>` stylesheets and global CSS files are still supported.

In production, all CSS Module files will be automatically concatenated into **many minified and code-split** `.css` files. These `.css` files represent hot execution paths in your application, ensuring the minimal amount of CSS is loaded for your application to paint.

### Sass Support

Next.js allows you to import Sass using both the `.scss` and `.sass` extensions. You can use component-level Sass via CSS Modules and the `.module.scss` or `.module.sass` extension.

Before you can use Next.js' built-in Sass support, be sure to install `sass`:

```
npm install sass
```

Sass support has the same benefits and restrictions as the built-in CSS support detailed above.

#### Customizing Sass Options

If you want to configure the Sass compiler you can do so by using `sassOptions` in `next.config.js`.

For example to add `includePaths`:

```javascript
const path = require('path')

module.exports = {
  sassOptions: {
    includePaths: [path.join(__dirname, 'styles')],
  },
}
```

### Less and Stylus Support

To support importing `.less` or `.styl` files you can use the following plugins:

* [@zeit/next-less](https://github.com/zeit/next-plugins/tree/master/packages/next-less)
* [@zeit/next-stylus](https://github.com/zeit/next-plugins/tree/master/packages/next-stylus)

If using the less plugin, don't forget to add a dependency on less as well, otherwise you'll see an error like:

```
Error: Cannot find module 'less'
```

### CSS-in-JS

**Examples**

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

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

export default HiThere
```

We bundle [styled-jsx](https://github.com/zeit/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](https://github.com/w3c/webcomponents/issues/71).

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

A component using `styled-jsx` looks like this:

```javascript
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](https://github.com/zeit/styled-jsx) for more examples.

### Related

For more information on what to do next, we recommend the following sections:
