Sorry, but you either have no stories or none are selected somehow.
If the problem persists, check the browser console, or the terminal you've run Storybook from.
All components, primitives and templates in Sitecore Discover UI Components can be themed following general industry practices as they use commonly accepted CSS properties or variables. CSS variables add a dynamic nature to an otherwise static language.
Discover JS SDK assigns values to the styles at runtime. You do not need a CSS preprocessor like SASS. It is very simple to alter the look and feel of your application by changing the value of a CSS variable.
In this section, you can find details on: