Install @once-ui-system/core, wrap your app in providers, and you're ready to build.
Install
Once UI targets Next.js App Router (React 18+). The package includes components, SCSS tokens, contexts, and the AI harness under @once-ui-system/core/ai/.
Minimal setup
Wrap your root layout with the theme and layout providers from the package:
Import @once-ui-system/core/styles once in your root layout
Wrap children with ThemeProvider and LayoutProvider from @once-ui-system/core
Full setup code and provider options are in the config guide.
Config (optional)
Most projects work with defaults. When you need customization:
Theme — color scheme, accent, border style, surface fill via provider props or data attributes on the html element
Layout — max content widths, breakpoint values via the layout provider
Dev workflow
To iterate on the library while building an app:The apps/dev sandbox in the monorepo is a live component playground — useful for seeing variants before you write docs or lessons.