Top nav — paper + navy variants
The 72-px tall site header in both surface variants. Identical structure (brand left, links centre, primary CTA right); only the colour palette flips between paper-on-light pages and navy-on-dark heroes.
Top nav · paper variant
Unless
Top nav · navy variant
Unless
Sub-nav — horizontal tab strip
Used inside the page body to slice a single surface into multiple views (Overview / Train / Test / Deploy / Analyze). Active tab carries the peak-blue underline; others sit in --fg-secondary.
Mobile drawer — full-height side-sheet
Below the md breakpoint, the top nav's link cluster collapses to a hamburger. Tap opens a full-height side-sheet from the right; backdrop fades in 120 ms, panel slides 200 ms.