# Basics

- [MVU](/3.0-preview/basics/mvu.md): Model-View-Update
- [Application state](/3.0-preview/basics/application-state.md)
- [Commands](/3.0-preview/basics/application-state/commands.md)
- [State validation](/3.0-preview/basics/application-state/state-validation.md)
- [User interface](/3.0-preview/basics/user-interface.md)
- [Widgets and modifiers](/3.0-preview/basics/user-interface/widgets-and-modifiers.md): The building blocks of a declarative UI
- [Styling](/3.0-preview/basics/user-interface/styling.md)
- [Animations](/3.0-preview/basics/user-interface/animations.md)
- [Testing](/3.0-preview/basics/testing.md)
- [Error monitoring](/3.0-preview/basics/error-monitoring.md)