.ui-navbar is a 44px sticky bar: brand (display face, with an optional mono .ui-navbar__version), .ui-navbar__items links, and .ui-navbar__actions at the right.

Add data-autohide and the bar slides up out of view while scrolling down and returns when scrolling up; at the top of the page it is always shown. It stays visible while its menu is open or a control has keyboard focus. design.js wires it (initNavbar); React uses Navbar and NavbarLink.

Below 768px the items fold into a menu behind .ui-navbar__toggle, and .ui-navbar__wide (readouts, clocks) is hidden. Keep tier badges and other long labels out of the bar. Actions stay visible: use an icon-only button at phone width. Mark the current link with aria-current.