silverstripe-webpack/app/client/src/scss/app.scss

// Your custom variables
@import "_variables";

@import "_components/_ui.bootstrap";

// By default we prefer font awesome CDN
//@import "_components/_ui.fontawesome";
@import "_components/_ui.lightbox";

@import "_components/_ui.main";
@import "_components/_ui.elemental";

// Your custom styling
@import "_typography";
@import "_layout";