Top bar at 320px (mock)
Panel A (proposed): below 375px the gaps between the bar's controls drop from 10px to 4px, so navigation, the Beta lockup, Search, Ask Holoh, Update and the account menu fit in 320px. Tap targets keep their current sizes: the icon buttons stay 44px and the account menu stays 32px. 375px and up is unchanged.
A · tighter gaps below 375px
B (alternative) · Update in the account menu
Gaps stay at 10px; below 375px Update leaves the bar and becomes the first row of the account menu, one tap further away.