/* Phase N (2026-04-22) — the horizontal-pill nav has been retired
       in favour of the /home app overview. This constant is kept empty so
       every route that still does `<style>{_BASE_CSS}{_NAV_CSS}...`
       keeps parsing; the shell itself now lives entirely inside
       _BASE_CSS (the .k6-shell / .k6-topbar rules).
       Delete this constant in a future cleanup once no route still
       interpolates it. */