Headless UI Primitives & Unstyled Foundations

Building complex interactive components like Accessible Dropdowns, Dialogs, Comboboxes, and Tooltips from scratch takes hundreds of hours of edge-case testing (keyboard focus traps, ARIA attributes, screen reader announcements, collision detection).

Modern design system teams increasingly build on top of Headless UI Primitives (such as Radix UI, React Aria, Floating UI, or Headless UI):

• The Headless Layer: Manages 100% of the accessibility, state logic, keyboard events, and ARIA attributes without providing any CSS styling.
• The Design System Layer: Applies the company's brand tokens, animations, and visual styling on top of the headless primitive.

This division of labor allows design system teams to deliver bulletproof accessibility in days instead of months.