The icon-only rail forced first-time users to guess (usertest:
Senior, a11y, UX personas). Three changes:
- Nav tooltips appear instantly and carry the page shortcut
(Cmd+1..9, Ctrl on non-mac — Ctrl activators added); expanded
labels show the same hint. Explicit button semantics for
screen readers on every destination.
- A visible 'Search & commands' row above the footer opens the
existing Cmd+K palette, which nothing in the UI advertised.
- Settings -> Appearance gains 'Keep the navigation expanded':
pins the rail with permanent labels (persisted preference).
Footer strip and pillar toggle made overflow-safe for the
animating rail; responsive test scrolls the by-design scrollable
destinations list.
Signed-off-by: flemming-it <stefan.a.flemming@googlemail.com>
