ui: 全站统一暗色主题设计系统

- globals.css 定义语义化 token (background/surface/elevated/border/muted/dim/accent)
- 所有页面和组件迁移至暗色 token，移除硬编码 bg-white/text-zinc-*/bg-gray-*
- RestaurantCard 和 MatchResult 适配暗色卡片风格
- 按钮颜色分层：系统CTA(accent)/模式强调(橙/紫)/危险(rose)/次级(surface)
- 修复 room 页深色文字在深背景不可见的可访问性问题

src/components/LeaveConfirmModal.tsx

@@ -26,7 +26,7 @@ export default function LeaveConfirmModal({
       {open && (
         <motion.div
           ref={backdropRef}
-          className="fixed inset-0 z-50 flex items-center justify-center bg-black/40 backdrop-blur-sm"
+          className="fixed inset-0 z-50 flex items-center justify-center bg-black/60 backdrop-blur-sm"
           initial={{ opacity: 0 }}
           animate={{ opacity: 1 }}
           exit={{ opacity: 0 }}
@@ -34,34 +34,34 @@ export default function LeaveConfirmModal({
           onClick={handleBackdropClick}
         >
           <motion.div
-            className="mx-6 w-full max-w-xs rounded-2xl bg-white px-6 py-6 shadow-2xl"
+            className="mx-6 w-full max-w-xs rounded-2xl bg-surface px-6 py-6 shadow-2xl ring-1 ring-border"
             initial={{ scale: 0.9, opacity: 0 }}
             animate={{ scale: 1, opacity: 1 }}
             exit={{ scale: 0.9, opacity: 0 }}
             transition={{ type: "spring", damping: 25, stiffness: 350 }}
           >
             <div className="flex flex-col items-center">
-              <div className="flex h-12 w-12 items-center justify-center rounded-full bg-rose-50">
-                <LogOut size={22} className="text-rose-500" />
+              <div className="flex h-12 w-12 items-center justify-center rounded-full bg-rose-500/15">
+                <LogOut size={22} className="text-rose-400" />
               </div>
 
-              <h2 className="mt-4 text-base font-bold text-zinc-900">
+              <h2 className="mt-4 text-base font-bold text-white">
                 确定要退出房间吗？
               </h2>
-              <p className="mt-1.5 text-center text-xs leading-relaxed text-zinc-400">
+              <p className="mt-1.5 text-center text-xs leading-relaxed text-muted">
                 退出后你的滑卡进度不会丢失，可以用房间号重新加入
               </p>
 
               <div className="mt-5 flex w-full gap-2.5">
                 <button
                   onClick={onCancel}
-                  className="flex h-11 flex-1 items-center justify-center rounded-xl border border-zinc-200 bg-white text-sm font-semibold text-zinc-700 transition-colors active:bg-zinc-50"
+                  className="flex h-11 flex-1 items-center justify-center rounded-xl bg-elevated text-sm font-semibold text-gray-300 ring-1 ring-border transition-colors active:bg-subtle"
                 >
                   继续滑卡
                 </button>
                 <button
                   onClick={onConfirm}
-                  className="flex h-11 flex-1 items-center justify-center rounded-xl bg-rose-500 text-sm font-semibold text-white shadow-md shadow-rose-200 transition-colors active:bg-rose-600"
+                  className="flex h-11 flex-1 items-center justify-center rounded-xl bg-rose-500 text-sm font-semibold text-white shadow-lg shadow-rose-500/20 transition-colors active:bg-rose-600"
                 >
                   退出房间
                 </button>