.demo-header {
            background: #ffffff;
            padding: 16px 24px;
            box-shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
            display: flex;
            align-items: center;
            justify-content: space-between;
            position: relative;
            z-index: 10;
        }

        .demo-header .logo {
            font-size: 18px;
            font-weight: 600;
            color: #0f172a;
            letter-spacing: -0.3px;
        }
        .demo-header .logo span {
            color: #3b82f6;
        }
        .demo-header .nav-placeholder {
            display: flex;
            gap: 24px;
            font-size: 14px;
            color: #64748b;
        }
        .demo-header .nav-placeholder a {
            color: inherit;
            text-decoration: none;
            transition: color 0.2s;
        }
        .demo-header .nav-placeholder a:hover {
            color: #0f172a;
        }

        .demo-content {
            flex: 1;
            padding: 48px 32px;
            max-width: 720px;
            margin: 0 auto;
            width: 100%;
        }
        .demo-content h1 {
            font-size: 28px;
            font-weight: 600;
            margin-bottom: 12px;
            letter-spacing: -0.5px;
        }
        .demo-content p {
            font-size: 16px;
            line-height: 1.7;
            color: #475569;
            margin-bottom: 16px;
        }
        .demo-content .badge {
            display: inline-block;
            background: #dbeafe;
            color: #1d4ed8;
            padding: 4px 14px;
            border-radius: 20px;
            font-size: 13px;
            font-weight: 500;
        }

        .demo-footer {
            background: #ffffff;
            padding: 14px 24px;
            border-top: 1px solid #e2e8f0;
            text-align: center;
            font-size: 13px;
            color: #94a3b8;
            margin-top: auto;
        }

        /* ============================================================
                   1. 语言选择器组件样式
                   ============================================================ */

        #langSwitcher {
            position: fixed;
            z-index: 29999;
            /* 默认 PC 位置：右上角 */
            top: 16px;
            right: 24px;
        }

        .lp-container {
            position: relative;
            display: inline-block;
            font-family: inherit;
        }

        /* ---- 触发按钮 ---- */
        .lp-btn {
            display: flex;
            align-items: center;
            gap: 8px;
            padding: 6px 14px 6px 10px;
            background: #ffffff;
            border: 1px solid #e2e8f0;
            border-radius: 24px;
            box-shadow: 0 1px 4px rgba(0, 0, 0, 0.04);
            cursor: pointer;
            font-size: 13px;
            font-weight: 500;
            color: #1e293b;
            line-height: 1.4;
            transition: all 0.2s ease;
            touch-action: manipulation;
            user-select: none;
            white-space: nowrap;
        }
        .lp-btn:hover {
            background: #f8fafc;
            border-color: #cbd5e1;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
        }
        .lp-btn:active {
            transform: scale(0.96);
        }
        .lp-btn .lp-current-flag {
            font-size: 18px;
            line-height: 1;
        }
        .lp-btn .lp-current-code {
            font-size: 12px;
            font-weight: 600;
            color: #475569;
            letter-spacing: 0.3px;
        }
        .lp-btn .lp-chevron {
            margin-left: 2px;
            font-size: 12px;
            color: #94a3b8;
            transition: transform 0.25s ease;
        }

        /* ---- 遮罩层 ---- */
        .lp-overlay {
            position: fixed;
            inset: 0;
            z-index: 9999;
            display: flex;
            align-items: center;
            justify-content: center;
            background: rgba(15, 23, 42, 0.25);
            backdrop-filter: blur(2px);
            -webkit-backdrop-filter: blur(2px);
            opacity: 0;
            visibility: hidden;
            transition: opacity 0.25s ease, visibility 0.25s ease;
        }
        .lp-overlay.is-open {
            opacity: 1;
            visibility: visible;
        }

        /* ---- 弹窗卡片 ---- */
        .lp-popup {
            /* 宽度由媒体查询控制，默认PC宽280px */
            width: 280px;
            max-width: 92vw;
            max-height: 80vh;
            background: #ffffff;
            border-radius: 20px;
            box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15), 0 8px 24px rgba(0, 0, 0, 0.05);
            padding: 8px 6px;
            transform: scale(0.92) translateY(12px);
            transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), opacity 0.25s ease;
            opacity: 0;
            overflow-y: auto;
            overscroll-behavior: contain;
            scrollbar-width: thin;
            scrollbar-color: #e2e8f0 transparent;
        }
        .lp-overlay.is-open .lp-popup {
            transform: scale(1) translateY(0);
            opacity: 1;
        }
        .lp-popup::-webkit-scrollbar {
            width: 4px;
        }
        .lp-popup::-webkit-scrollbar-track {
            background: transparent;
        }
        .lp-popup::-webkit-scrollbar-thumb {
            background: #e2e8f0;
            border-radius: 10px;
        }

        /* ---- 选项 ---- */
        .lp-item {
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 10px 16px;
            border-radius: 14px;
            cursor: pointer;
            transition: background 0.15s ease;
            touch-action: manipulation;
            min-height: 44px;
        }
        .lp-item:hover {
            background: #f1f5f9;
        }
        .lp-item:active {
            background: #e2e8f0;
            transform: scale(0.98);
        }
        .lp-item .lp-flag {
            font-size: 22px;
            line-height: 1;
            flex-shrink: 0;
            width: 32px;
            text-align: center;
        }
        .lp-item .lp-label {
            flex: 1;
            font-size: 15px;
            font-weight: 450;
            color: #0f172a;
            letter-spacing: -0.2px;
        }
        .lp-item .lp-check {
            flex-shrink: 0;
            color: #3b82f6;
            font-size: 18px;
            font-weight: 600;
            opacity: 0;
            transform: scale(0.5);
            transition: opacity 0.2s ease, transform 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
        }
        .lp-item.is-selected .lp-check {
            opacity: 1;
            transform: scale(1);
        }
        .lp-item.is-selected {
            background: #eff6ff;
        }
        .lp-item.is-selected .lp-label {
            font-weight: 550;
            color: #1d4ed8;
        }

        .lp-popup .lp-footer {
            padding: 8px 16px 4px;
            font-size: 11px;
            color: #94a3b8;
            text-align: center;
            border-top: 1px solid #f1f5f9;
            margin-top: 4px;
        }

        /* ============================================================
                   2. 响应式定位 —— 优化移动端
                   ============================================================ */

        /* ---- PC / 大屏（≥1024px）：右上角 ---- */
        @media (min-width: 1024px) {
            #langSwitcher {
                top: 16px;
                right: 24px;
                bottom: auto;
                left: auto;
                z-index: 29999;
            }
        }

        /* ---- 移动端 / 平板（<1024px）：右下角，且弹窗加宽 ---- */
        @media (max-width: 1023px) {
           /*    #langSwitcher {
                top: auto;
                right: 50%;
                bottom: 24px;
                left: auto;
                   z-index: 29999;
            } */


            #langSwitcher {
                   top: 24px;
                right: 16px;
                bottom: auto;
                left: auto;
                z-index: 29999;
            }

            /* 移动端按钮微调 */
            .lp-btn {
                padding: 5px 12px 5px 8px;
                font-size: 12px;
                border-radius: 20px;
                box-shadow: 0 2px 12px rgba(0, 0, 0, 0.10);
            }
            .lp-btn .lp-current-flag {
                font-size: 16px;
            }
            .lp-btn .lp-current-code {
                font-size: 11px;
            }

            /* 弹窗宽度增加 */
            .lp-popup {
                width: auto;
                min-width: 300px;   /* 保证最小宽度 */
                max-width: 92vw;    /* 适应屏幕宽度 */
                padding: 12px 8px;  /* 增加内边距 */
                border-radius: 18px;
            }

            .lp-item {
                padding: 12px 16px;
                min-height: 48px;
                gap: 14px;
            }
            .lp-item .lp-flag {
                font-size: 24px;
                width: 36px;
            }
            .lp-item .lp-label {
                font-size: 16px;
            }
            .lp-item .lp-check {
                font-size: 20px;
            }
        }

        /* ---- 超小屏手机（<480px）保持加宽，但进一步缩小边距 ---- */
        @media (max-width: 480px) {
         /*   #langSwitcher {
                right: 50%;
                bottom: 16px;
                   z-index: 29999;
            } */

  #langSwitcher {
                top: 24px;
                right: 16px;
                bottom: auto;
                left: auto;
                z-index: 29999;
            }

            .lp-btn {
                padding: 8px 8px 8px 4px;
                font-size: 11px;
                border-radius: 18px;
            }
            .lp-btn .lp-current-flag {
                font-size: 14px;
            }
            .lp-btn .lp-current-code {
                font-size: 10px;
            }
            .lp-btn .lp-chevron {
                font-size: 10px;
            }

            .lp-popup {
                min-width: 260px;
                max-width: 94vw;
                padding: 8px 4px;
            }
            .lp-item {
                padding: 8px 12px;
                min-height: 40px;
                gap: 10px;
            }
            .lp-item .lp-flag {
                font-size: 20px;
                width: 28px;
            }
            .lp-item .lp-label {
                font-size: 14px;
            }
            .lp-item .lp-check {
                font-size: 16px;
            }
        }

        /* ============================================================
                   3. 暗色模式（同前，略）
                   ============================================================ */
        @media (prefers-color-scheme: dark) {
            body {
                background: #0f172a;
                color: #e2e8f0;
            }
            .demo-header {
                background: #1e293b;
                box-shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
            }
            .demo-header .logo {
                color: #f1f5f9;
            }
            .demo-header .nav-placeholder a {
                color: #94a3b8;
            }
            .demo-header .nav-placeholder a:hover {
                color: #f1f5f9;
            }
            .demo-content p {
                color: #94a3b8;
            }
            .demo-content .badge {
                background: #1e293b;
                color: #60a5fa;
            }
            .demo-footer {
                background: #1e293b;
                border-top-color: #334155;
                color: #64748b;
            }

            .lp-btn {
                background: #1e293b;
                border-color: #334155;
                color: #f1f5f9;
            }
            .lp-btn:hover {
                background: #263348;
                border-color: #475569;
            }
            .lp-btn .lp-current-code {
                color: #94a3b8;
            }
            .lp-btn .lp-chevron {
                color: #64748b;
            }
            .lp-overlay {
                background: rgba(0, 0, 0, 0.55);
                backdrop-filter: blur(3px);
                -webkit-backdrop-filter: blur(3px);
            }
            .lp-popup {
                background: #1e293b;
                box-shadow: 0 20px 60px rgba(0, 0, 0, 0.6);
            }
            .lp-item:hover {
                background: #2d3a4a;
            }
            .lp-item:active {
                background: #3a4a5e;
            }
            .lp-item .lp-label {
                color: #f1f5f9;
            }
            .lp-item.is-selected {
                background: #1a365d;
            }
            .lp-item.is-selected .lp-label {
                color: #93bbfc;
            }
            .lp-item .lp-check {
                color: #60a5fa;
            }
            .lp-popup .lp-footer {
                border-top-color: #334155;
                color: #64748b;
            }
        }

        @media (prefers-reduced-motion: reduce) {
            .lp-btn,
            .lp-overlay,
            .lp-popup,
            .lp-item,
            .lp-item .lp-check {
                transition-duration: 0.01ms !important;
                animation-duration: 0.01ms !important;
            }
        }