Fuse fully takes advantage of Angular Material's theming.
To simply explain, every component that comes with Fuse has a separate *.theme.scss file
which has everything theming related. These files are separate from the component's scss files simply
because they have theming mixins and they need to be imported in app.theme.scss. Having those
mixins in the component's scss file would have caused duplicate content when imported.
Below, you can see an example theme (calendar.theme.scss) file. When you create a component, or
move one from the Demo app, you need to import this scss file in the app.theme.scss file and add it
to the component-theme mixin array.
calendar.theme.scss
app.theme.scss
The components-theme mixin will be called when you define a new theme so that the components
can be styles according to that theme.