feat: add depth to game

lib/core/theme/app_theme.dart

@@ -56,12 +56,19 @@ class AppTheme {
           backgroundColor: AppColors.accent,
           foregroundColor: AppColors.text,
           minimumSize: const Size.fromHeight(54),
+          elevation: 8,
+          shadowColor: Colors.black,
           textStyle: const TextStyle(
               fontFamily: fontFamily, fontSize: 18, fontWeight: FontWeight.bold),
           shape: RoundedRectangleBorder(
             borderRadius: BorderRadius.circular(14),
             side: const BorderSide(color: AppColors.gold, width: 1.5),
           ),
+        ).copyWith(
+          // افکتِ فشار: کمی فرورفتن هنگام لمس برای حسِ عمق.
+          elevation: WidgetStateProperty.resolveWith(
+            (states) => states.contains(WidgetState.pressed) ? 2.0 : 8.0,
+          ),
         ),
       ),
     );