Import [Bootstrap's JavaScript]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/javascript/) by adding this line to your app's entry point (usually `index.js` or `app.js`):
First, create your own `_custom.scss` and use it to override the [built-in custom variables]({{ site.baseurl }}/docs/{{ site.docs_version }}/getting-started/theming/). Then, use your main Sass file to import your custom variables, followed by Bootstrap:
For Bootstrap to compile, make sure you install and use the required loaders: [sass-loader](https://github.com/webpack-contrib/sass-loader), [postcss-loader](https://github.com/webpack-contrib/postcss-loader) with [Autoprefixer](https://github.com/postcss/autoprefixer#webpack). With minimal setup, your webpack config should include this rule or similar:
In this case you may use your existing rule for `css` without any special modifications to webpack config, except you don't need `sass-loader` just [style-loader](https://github.com/webpack-contrib/style-loader) and [css-loader](https://github.com/webpack-contrib/css-loader).