Home menu UNO-style UX refactor (tactile, hero Play)

Keep the Persian-luxury palette, adopt casual card-game UX:
- New .press-3d primitive (solid underside that compresses on tap, reduced-motion
  aware) for tactile buttons.
- Home: a large glowing hero "Play online" button (Play icon + chevron), a
  tactile vs-computer card, and chunkier mode tiles with color-tinted icon chips
  (teal/sky/gold/rose). All handlers + i18n unchanged.

Verified: tsc + next build clean; web rebuilt :1500.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

src/app/globals.css

@@ -59,6 +59,20 @@
   box-shadow: 0 0 10px rgba(212, 175, 55, 0.45);
 }
 
+/* Tactile "3D press" buttons (casual card-game feel) — a solid underside that
+   compresses on tap. Pair with a bg/glass class for the face. */
+.press-3d {
+  box-shadow: 0 6px 0 0 rgba(0, 0, 0, 0.30), 0 8px 16px rgba(0, 0, 0, 0.28);
+  transition: transform 0.08s ease, box-shadow 0.08s ease;
+}
+.press-3d:active {
+  transform: translateY(4px);
+  box-shadow: 0 2px 0 0 rgba(0, 0, 0, 0.30), 0 3px 8px rgba(0, 0, 0, 0.28);
+}
+@media (prefers-reduced-motion: reduce) {
+  .press-3d, .press-3d:active { transition: none; transform: none; }
+}
+
 /* HUD text stays legible over the dynamic felt/table (game-ui best practice). */
 .hud-shadow {
   text-shadow: 0 1px 2px rgba(0, 0, 0, 0.6), 0 0 6px rgba(0, 0, 0, 0.4);