UI And Theme Boundaries

Labkit UI is intentionally thin.

It provides:

• cx for class-name composition;
• typed theme definitions;
• theme-name validation;
• persisted theme controller mechanics;
• document root class application.

It does not provide buttons, fields, layouts, routes, surfaces, visual tokens, or product components.

Why

Product UI changes quickly and carries brand decisions. Sharing components too early creates false reuse. Labkit keeps only the mechanics that repeated apps need before they have a full design system.

When a second app creates real pressure to share components, create a separate design-system package rather than expanding Labkit runtime helpers into product UI.