Recently I've been building a site using Ionic 2 (which sits on top of Angular 2). The way it is structured encourages a single scss file per page/component. It feels much clearer to create and apply the css to individual components. So if you apply an enclosing class to the component with the name of the component you avoid any clashing styles. You do end up writing duplicate css but you don't have to keep track of it across a huge file.