Summary

Makes the mobile documentation sidebar fully dismissible while preserving its existing design, animation, and desktop behavior.

What

• Adds dismissal through the hamburger trigger, backdrop, navigation links, and Escape.
• Restores focus to the hamburger trigger after dismissal.
• Exposes the drawer state with accurate accessible attributes and labels.
• Prevents interaction and scrolling behind the open drawer while keeping the sidebar scrollable.
• Safely handles Escape when the playground samples popover is absent.
• Adds focused mobile and desktop regression coverage.

Why

The reason I made these changes is that navigating the documentation becomes difficult when I split my screen between the browser and my IDE.

Validation

• pnpm --filter=typescriptlang-org test
• pnpm test
• Manually tested at 390×844 in Helium:
  • trigger, backdrop, navigation-link, and Escape dismissal
  • focus restoration and accessible state
  • background interaction and scroll locking
  • independently scrollable sidebar
  • mobile-to-desktop and desktop-to-mobile resizing
  • repeated open/close cycles with no runtime errors