style(site): near-black button hover keeping 10% brand colour; no underline on buttons

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

site/assets/css/style.css

@@ -309,6 +309,7 @@ section[id] {
 
 /* ── Buttons ───────────────────────────────────────────────────────────────── */
 .site-btn {
+  text-decoration: none;   /* Bootstrap underlines every <a>; buttons never */
   display: inline-block;
   border: none;
   font-size: 1rem;
@@ -393,15 +394,15 @@ section[id] {
   }
 }
 
-/* Hover: white text on a deepened brand colour (≈5:1 contrast) — the bright
+/* Hover: white text on an almost-black face keeping ~10% of the brand colour —
-   neon faces around it then stand out against the darker face. The dark and
+   the bright neon faces around it then stand out against it. The dark and
    ghost variants keep their own backgrounds. */
 .site-btn:not(.sb-dark):not(.sb-line):not(.sb-ghost):hover,
 .site-btn:not(.sb-dark):not(.sb-line):not(.sb-ghost):focus-visible,
 .gym-switch-btn:hover,
 .gym-switch-btn:focus-visible {
-  background: color-mix(in srgb, var(--fitme-accent) 50%, #000);
+  background: color-mix(in srgb, var(--fitme-accent) 10%, #000);
-  border-color: color-mix(in srgb, var(--fitme-accent) 50%, #000);
+  border-color: color-mix(in srgb, var(--fitme-accent) 10%, #000);
   color: #fff;
   text-shadow: 0 1px 2px rgba(0, 0, 0, .35);
 }