CSS Boundaries Layouts

Use boundary files to keep CSS scoped to app sections.

Example structure

src/
  app/
    app.boss.css
    page.tsx
    admin/
      admin.boss.css
      page.tsx
  marketing/
    marketing.boss.css
    page.tsx

Import boundaries

// src/app/layout.tsx
import './app.boss.css'

// src/app/admin/layout.tsx
import './admin.boss.css'

// src/marketing/layout.tsx
import './marketing.boss.css'

Tips

• Keep boundary files empty; Boss overwrites them.
• Use css.boundaries.ignore to skip build artifacts.
• Shared rules are hoisted to the nearest common ancestor boundary or .bo$$/styles.css.