Now we'll have to add Bootstrap's CSS code to our application. Of course ,we can simply add a link to the CSS code on CDN in index.html, but doing that does not enable us to profit from the underlying Sass code.

Each component in our app can have its own styles sheets. The main styles of our app are loaded via the styles.css file in the root. We'll set up a build system that compiles Bootstrap's SCSS code and our own modification into the styles.css file.

First, we install Bootstrap's source code via npm by running the following command:

npm install bootstrap --save-dev

Then we set up a similar file structure as we have done already in the preceding chapters of this book:

scss/styles.scss 
scss/includes/_bootstrap.sccs 
scss/includes/_variables.sccs 
 

The scss/_includes/_variables.scss file enables us to override Bootstrap's default values and the scss/_includes/_bootstrap.scss file is a copy of the original bootstrap...