:root { 
   --bg: #ffffff; 
   --text: #1a1a1a; 
   --subtext: #4d4d4d; 
   --border: #e5e5e5; 
   --shadow: 0 8px 24px rgba(0,0,0,0.12); 
   --shadow-heavy: 0 20px 48px rgba(0,0,0,0.16); 
   --overlay: rgba(0, 0, 0, 0.4); 
   --accent: #0078d4; /* Windows 蓝 */ 
 }
 
 * { box-sizing: border-box; }
 html, body { height: 100%; }
 body {
   margin: 0;
   background: linear-gradient(135deg, #f0f4f8 0%, #e8eef5 50%, #dfe7f0 100%);
   color: var(--text);
   font-family: "Noto Sans SC", Segoe UI, system-ui, -apple-system, Roboto, Helvetica, Arial, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
   overflow: hidden;
 }
 
 #popup-layer {
   position: fixed;
   inset: 0;
   pointer-events: none; /* 允许下层点击通过（初始 modal 期间被遮罩覆盖） */
 }
 
 /* 入场弹窗 */
 .modal-backdrop {
   position: fixed;
   inset: 0;
   background: var(--overlay);
   display: grid;
   place-items: center;
   z-index: 9999;
 }
 
 .modal {
   width: min(92vw, 520px);
   background: #ffffff;
   border: 1px solid var(--border);
   border-radius: 8px;
   box-shadow: var(--shadow-heavy);
   text-align: left;
   overflow: hidden;
   animation: modal-appear 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275) forwards;
 }
 
 .modal .titlebar {
   display: flex;
   align-items: center;
   gap: 8px;
   padding: 12px 14px;
   background: #f3f3f3;
   border-bottom: 1px solid var(--border);
 }
 
 .modal .titlebar .icon { font-size: 18px; }
 .modal .titlebar .title { font-weight: 700; }
 
 .modal .content { padding: 16px 16px 8px; color: var(--subtext); }
 .modal .actions { padding: 0 16px 16px; display: flex; gap: 10px; justify-content: flex-end; }
 
 .btn {
   display: inline-flex;
   align-items: center;
   justify-content: center;
   gap: 8px;
   height: 36px;
   padding: 0 14px;
   border-radius: 4px;
   border: 1px solid var(--border);
   cursor: pointer;
   font-weight: 600;
   letter-spacing: .2px;
   background: #f7f7f7;
 }
 
 .btn.primary { background: var(--accent); color: #fff; border-color: #0a6ecf; }
 .btn:hover { filter: brightness(0.98); }
 .btn.primary:hover { filter: brightness(1.05); }
 .btn:active { transform: translateY(1px); }
 
 /* 屏幕弹窗（温馨提示） */
 .popup {
   position: absolute;
   width: 230px;
   color: var(--text);
   background: #ffffff;
   border-radius: 7px;
   border: 1px solid var(--border);
   box-shadow: 0 4px 16px rgba(0,0,0,0.15), 0 8px 32px rgba(0,0,0,0.08);
   font-size: 13px;
   line-height: 1.4;
   pointer-events: none;
   user-select: none;
   transform-origin: center;
   overflow: hidden;
 }
 
 .popup .header {
   display: flex;
   align-items: center;
   gap: 4px;
   padding: 3px 8px;
   background: #f3f3f3;
   border-bottom: 1px solid var(--border);
 }
 .popup .header .icon { font-size: 12px; }
 .popup .header .title { font-weight: 800; font-size: 11px; }
 
 .popup .content { padding: 6px 10px; color: var(--text); font-size: 18px; font-weight: 600; line-height: 1.25; text-align: center; }
 
 /* 不同颜色主题的弹窗背景 */
 .popup.theme-blue .header { background: #e3f2fd; border-bottom-color: #bbdefb; }
 .popup.theme-blue .content { background: #f1f8ff; }
 
 .popup.theme-green .header { background: #e8f5e9; border-bottom-color: #c8e6c9; }
 .popup.theme-green .content { background: #f1f8f4; }
 
 .popup.theme-orange .header { background: #fff3e0; border-bottom-color: #ffe0b2; }
 .popup.theme-orange .content { background: #fffaf3; }
 
 .popup.theme-purple .header { background: #f3e5f5; border-bottom-color: #e1bee7; }
 .popup.theme-purple .content { background: #faf5fc; }
 
 .popup.theme-pink .header { background: #fce4ec; border-bottom-color: #f8bbd0; }
 .popup.theme-pink .content { background: #fff0f5; }
 
 .popup.theme-yellow .header { background: #fffde7; border-bottom-color: #fff9c4; }
 .popup.theme-yellow .content { background: #fffef7; }
 
 .popup.theme-cyan .header { background: #e0f7fa; border-bottom-color: #b2ebf2; }
 .popup.theme-cyan .content { background: #f0fcff; }
 
 .popup.theme-lime .header { background: #f9fbe7; border-bottom-color: #f0f4c3; }
 .popup.theme-lime .content { background: #fdfef8; }
 
 .popup.theme-red .header { background: #ffebee; border-bottom-color: #ffcdd2; }
 .popup.theme-red .content { background: #fff5f5; }
 
 .popup.theme-teal .header { background: #e0f2f1; border-bottom-color: #b2dfdb; }
 .popup.theme-teal .content { background: #f0faf9; }
 
 .popup.theme-indigo .header { background: #e8eaf6; border-bottom-color: #c5cae9; }
 .popup.theme-indigo .content { background: #f3f4fb; }
 
 .popup.theme-amber .header { background: #fff8e1; border-bottom-color: #ffecb3; }
 .popup.theme-amber .content { background: #fffef5; }
 
 .popup.theme-rose .header { background: #fce4ec; border-bottom-color: #f8bbd0; }
 .popup.theme-rose .content { background: #fef5f8; }
 
 .popup.theme-mint .header { background: #e8f8f5; border-bottom-color: #c8ebe3; }
 .popup.theme-mint .content { background: #f5fcfa; }
 
 .popup.theme-peach .header { background: #fff0e5; border-bottom-color: #ffe0c7; }
 .popup.theme-peach .content { background: #fffaf5; }
 
 .popup.theme-lavender .header { background: #f0ebf8; border-bottom-color: #ddd0f0; }
 .popup.theme-lavender .content { background: #f9f6fc; }
 
 .popup.theme-coral .header { background: #ffe4e1; border-bottom-color: #ffc4bd; }
 .popup.theme-coral .content { background: #fff7f6; }
 
 .popup.theme-sky .header { background: #e1f5fe; border-bottom-color: #b3e5fc; }
 .popup.theme-sky .content { background: #f0fbff; }
 
 .popup.theme-lemon .header { background: #fffef0; border-bottom-color: #fff9c8; }
 .popup.theme-lemon .content { background: #fffffa; }
 
 @media (max-width: 640px) { 
   .popup { width: min(230px, 85vw); font-size: 13px; }
   .popup .content { font-size: 16px; }
 }
 
 /* 动画效果 */
 @keyframes modal-appear {
   0% {
     opacity: 0;
     transform: scale(0.7) translateY(-20px);
   }
   100% {
     opacity: 1;
     transform: scale(1) translateY(0);
   }
 }