The header's "Post a job" button (and "Sign in" when signed out) was unreadable
until you hovered it.
.nav a is more specific than .btn, so the button painted the nav link's
--muted-foreground on the button's own --primary background: oklch lightness
0.53 on 0.52 in light, 0.71 on 0.72 in dark, a contrast ratio of about 1.05:1
either way. Hover only looked like a fix because the nav's hover rule repainted
the element as a plain grey pill, throwing away the button's background and its
own hover state with it.
The nav link rules are now scoped with :not(.btn), so a button in the nav is
left to .btn and its --primary / --primary-foreground pair: 4.89:1 in
light, 8.32:1 in dark, with the darker-green hover a button should have.
The service worker VERSION follows the shell asset hash, so returning readers
get the new stylesheet instead of the cached one.