Below sm the sidebar had no replacement (nav was inaccessible on phones). The sidebar aside is now a responsive drawer: fixed + off-canvas with a hamburger toggle and backdrop on mobile, static in-flow on sm+ (same markup, no duplication). Closes on nav-click, backdrop, Esc, or route change. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01FRgehjoz7Yv8LkUfADxACm