@maa/monkey-sass v0.1.1
Next.js + Sass
Import .sass or .scss files in your Next.js project
Installation
npm install --save @zeit/next-sass node-sassor
yarn add @zeit/next-sass node-sassUsage
The stylesheet is compiled to .next/static/css. Next.js will automatically add the css file to the HTML. 
In production a chunk hash is added so that styles are updated when a new version of the stylesheet is deployed.
Without CSS modules
Create a next.config.js in your project
// next.config.js
const withSass = require('@zeit/next-sass')
module.exports = withSass({
  /* config options here */
})Create a Sass file styles.scss
$font-size: 50px;
.example {
  font-size: $font-size;
}Create a page file pages/index.js
import "../styles.scss"
export default () => <div className="example">Hello World!</div>With CSS modules
// next.config.js
const withSass = require('@zeit/next-sass')
module.exports = withSass({
  cssModules: true
})Create a Sass file  styles.scss
$font-size: 50px;
.example {
  font-size: $font-size;
}Create a page file pages/index.js
import css from "../styles.scss"
export default () => <div className={css.example}>Hello World!</div>With CSS modules and options
You can also pass a list of options to the css-loader by passing an object called cssLoaderOptions.
For instance, to enable locally scoped CSS modules, you can write:
// next.config.js
const withSass = require('@zeit/next-sass')
module.exports = withSass({
  cssModules: true,
  cssLoaderOptions: {
    importLoaders: 1,
    localIdentName: "[local]___[hash:base64:5]",
  }
})Create a SCSS file style.scss
.example {
  font-size: 50px;
}Create a page file pages/index.js that imports your stylesheet and uses the hashed class name from the stylesheet
import css from "../style.scss"
const Component = props => {
  return (
    <div className={css.example}>
      ...
    </div>
  )
}
export default ComponentYour exported HTML will then reflect locally scoped CSS class names.
For a list of supported options, refer to the webpack css-loader README.
With SASS loader options
You can pass options from node-sass
// next.config.js
const withSass = require('@zeit/next-sass')
module.exports = withSass({
  sassLoaderOptions: {
    includePaths: ["absolute/path/a", "absolute/path/b"]
  }
})PostCSS plugins
Create a next.config.js in your project
// next.config.js
const withSass = require('@zeit/next-sass')
module.exports = withSass({
  /* config options here */
})Create a postcss.config.js
module.exports = {
  plugins: {
    // Illustrational
    'postcss-css-variables': {}
  }
}Create a CSS file styles.scss the CSS here is using the css-variables postcss plugin.
:root {
  --some-color: red;
}
.example {
  /* red */
  color: var(--some-color);
}When postcss.config.js is not found postcss-loader will not be added and will not cause overhead.
You can also pass a list of options to the postcss-loader by passing an object called postcssLoaderOptions.
For example, to pass theme env variables to postcss-loader, you can write:
// next.config.js
const withSass = require('@zeit/next-sass')
module.exports = withSass({
  postcssLoaderOptions: {
    parser: true,
    config: {
      ctx: {
        theme: JSON.stringify(process.env.REACT_APP_THEME)
      }
    }
  }
})Configuring Next.js
Optionally you can add your custom Next.js configuration as parameter
// next.config.js
const withSass = require('@zeit/next-sass')
module.exports = withSass({
  webpack(config, options) {
    return config
  }
})