coss ui component library built on Base UI and Tailwind CSS for React applications. Copy-paste ownership model with 50+ accessible, composable components. Use when: (1) Building React UI with coss ui components (Accordion, Alert, Button, Dialog, Select, Tabs, Toast, etc.), (2) Installing or setting up coss ui in a project, (3) Styling coss ui components with CSS variables and color tokens, (4) Migrating from shadcn/ui or Radix UI to coss ui (asChild to render prop, component renaming), (5) Using Base UI primitives with coss ui wrappers, (6) Implementing forms with Field, Fieldset, Form, and validation, (7) Working with any @coss/* component package, (8) Writing React code that imports from @/components/ui/*.