Composition model
Components are designed to be combined rather than configured through long prop lists. Small, single-purpose pieces compose into the larger patterns you actually need on a page.
Layout primitives
Layout primitives handle spacing and alignment so individual components don't need to reimplement it. Reach for these first before adding custom spacing rules.
Interactive components
Interactive components manage their own internal state (open/closed, selected/unselected) but always expose a controlled mode for cases where the surrounding app needs to own that state instead.
Where to go from here
Revisit Theming to restyle any component
Return to the Quickstart for a refresher on the basics
Check Configuration for instance-level behavior options