style(site): button hover wall 4px with graded sides and lit bevel

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

site/assets/css/style.css

@@ -363,7 +363,7 @@ section[id] {
 .gym-switch-btn {
   --neon: color-mix(in srgb, var(--fitme-accent) 70%, #fff);
   --neon-edge: var(--fitme-accent-dark);
-  --depth: 3px;
+  --depth: 4px;
 }
 
 @media (hover: hover) and (prefers-reduced-motion: no-preference) {
@@ -381,11 +381,13 @@ section[id] {
        settling toward the wall) and a soft glow round the whole solid. The
        face itself stays plain — no second outline, so nothing reads as a copy. */
     box-shadow:
+      inset 1px 1px 0 rgba(var(--fitme-accent-rgb), .55),     /* lit top-left bevel on the face */
       1px 1px 0 var(--neon),
       2px 2px 0 var(--fitme-accent),
-      3px 3px 0 color-mix(in srgb, var(--fitme-accent) 70%, #000),
-      0 0 18px 3px rgba(var(--fitme-accent-rgb), .45),
-      3px 3px 22px 2px rgba(var(--fitme-accent-rgb), .3);
+      3px 3px 0 color-mix(in srgb, var(--fitme-accent) 75%, #000),
+      4px 4px 0 color-mix(in srgb, var(--fitme-accent) 50%, #000),
+      0 0 18px 3px rgba(var(--fitme-accent-rgb), .4),
+      4px 4px 22px 2px rgba(var(--fitme-accent-rgb), .3);
   }
 
   .site-btn:active,