feat(gyms): per-gym brand colour; CrossFit pill follows it

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

site/assets/css/style.css

@@ -28,6 +28,8 @@
      (WCAG AA needs 4.5:1), so text uses this darker olive. Bright accent stays
      for dark sections and button backgrounds. */
   --fitme-accent-ink: #667000;
+  /* readable text colour on top of --fitme-accent (a gym's brand colour may be dark) */
+  --fitme-on-accent: #0B0B0D;
   /* deeper moss for hover / active */
 
   /* The Anchor — Void Black, and a cool ramp lifting toward Charcoal Slate. */
@@ -314,7 +316,7 @@ section[id] {
   min-width: 200px;
   padding: 16px 36px;
   background: var(--fitme-accent);
-  color: var(--fitme-dark);
+  color: var(--fitme-on-accent);
   text-align: center;
   cursor: pointer;
   border-radius: var(--fitme-radius);
@@ -325,7 +327,7 @@ section[id] {
 
 .site-btn:hover {
   background: var(--fitme-accent-dark);
-  color: var(--fitme-dark);
+  color: var(--fitme-on-accent);
   transform: translateY(-1px);
   box-shadow: 0 4px 16px rgba(var(--fitme-accent-rgb), .35);
 }
@@ -384,13 +386,13 @@ section[id] {
   background: transparent !important;
 }
 
-/* ── CrossFit nav pill ─────────────────────────────────────────────────────── */
+/* ── CrossFit nav pill (follows the gym's brand colour) ─────────────────────────────────────────────────────── */
 .crossfit-nav-link {
-  color: #b71c1c !important;
+  color: var(--fitme-accent-ink) !important;
   font-weight: 700;
   text-transform: uppercase;
   letter-spacing: .5px;
-  border: 2px solid #b71c1c;
+  border: 2px solid var(--fitme-accent-ink);
   border-radius: var(--fitme-radius);
   padding: 6px 14px !important;
   transition: background-color var(--fitme-transition), color var(--fitme-transition);
@@ -404,15 +406,16 @@ section[id] {
    generic .nav-item.active .nav-link transparent-background rule above) */
 .crossfit-nav-link:hover,
 .nav-item.active .crossfit-nav-link {
-  background: #b71c1c !important;
-  color: #fff !important;
+  background: var(--fitme-accent) !important;
+  border-color: var(--fitme-accent);
+  color: var(--fitme-on-accent) !important;
 }
 
 /* ── Other-gym button (right end of the navbar) ────────────────────────────── */
 .gym-switch-btn {
   display: inline-block;
   background: var(--fitme-accent);
-  color: var(--fitme-dark);
+  color: var(--fitme-on-accent);
   font-weight: 700;
   text-transform: uppercase;
   letter-spacing: .5px;