On viewports < 768px (md breakpoint): - Sidebar slides in as a drawer with dark overlay backdrop - Hamburger button in the header toggles the sidebar - Nav link clicks auto-close the drawer - Sidebar items get 44px min-height for touch-friendly tapping - Search input uses fluid width instead of fixed 320px Desktop (>= 768px) behavior is unchanged: sidebar always visible, main content offset by 260px, no hamburger button. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>