- CSS: pos-bottom-nav changed from flex row (height:52px, bottom bar) to flex column (width:64px, right sidebar) with vertical tab layout - Active tab indicator: top horizontal bar → left vertical bar - Tab hover: subtle background highlight - CafeDesktop.razor: wrap content + nav in flex row container - Mobile responsive: compact 52px width on small screens Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>