Normalize the chat content rail around the input composer as the width baseline. This introduces shared rail variables, compensates message content for the actual scrollbar gutter, and separates mobile/webview behavior so desktop, mobile web, and app shell layouts stay centered consistently.
Align assistant text, markdown blocks, tables, minimal-mode summaries, expanded minimal steps, slash/runtime/git floating UI, and brief-message separators to the same horizontal rail. Remove the collapsed right resize handle and mobile menu glow while preserving the intended percentage widths for floating composer affordances.
Validation: npm run build --silent 2>&1 | tail -n 5
JOJO
d095531bb8