/* 基础样式重置和变量定义 */
        :root {
            --primary: #4a6cf7;
            --primary-dark: #3a56d7;
            --secondary: #10b981;
            --danger: #ef4444;
            --warning: #f59e0b;
            --dark: #1e293b;
            --light: #f8fafc;
            --gray: #64748b;
            --border-radius: 12px;
            --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
            --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
        }

        .cloud-server-container {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(380px, 1fr));
            gap: 30px;
            max-width: 1400px;
            margin: 100px auto;
        }

        /* 服务器卡片 */
        .server-card {
            background: white;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow);
            overflow: hidden;
            transition: var(--transition);
            position: relative;
            border: 1px solid #e2e8f0;
            transform: translateY(0);
        }

        .server-card:hover {
            transform: translateY(-8px);
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.15);
            border-color: var(--primary);
        }

        /* 库存徽章 */
        .stock-badge {
            position: absolute;
            top: 16px;
            right: 16px;
            background: linear-gradient(135deg, var(--secondary), #0ca678);
            color: white;
            padding: 6px 16px;
            border-radius: 20px;
            font-size: 13px;
            font-weight: 600;
            z-index: 2;
            box-shadow: 0 2px 8px rgba(16, 185, 129, 0.3);
        }

        /* 卡片头部 */
        .card-header {
            padding: 24px 24px 16px;
            border-bottom: 1px solid #f1f5f9;
            position: relative;
            background: linear-gradient(to right, #f8fafc, #ffffff);
        }

        .server-title {
            margin: 0;
            color: var(--dark);
            font-size: 22px;
            font-weight: 700;
            line-height: 1.4;
            display: flex;
            align-items: center;
            gap: 8px;
        }

        .server-title::before {
            font-size: 20px;
        }

        .server-tag {
            display: inline-block;
            background: linear-gradient(135deg, #f97316, #f59e0b);
            color: white;
            padding: 6px 16px;
            border-radius: 20px;
            font-size: 13px;
            font-weight: 600;
            margin-top: 10px;
            box-shadow: 0 2px 8px rgba(249, 115, 22, 0.3);
        }

        /* 规格列表 */
        .server-specs {
            padding: 20px 24px;
        }

        .spec-item {
            display: flex;
            align-items: center;
            padding: 12px 0;
            border-bottom: 1px solid #f1f5f9;
            font-size: 15px;
            color: #475569;
            transition: var(--transition);
        }

        .spec-item:last-child {
            border-bottom: none;
        }

        .spec-item.highlight {
            background: linear-gradient(135deg, rgba(74, 108, 247, 0.1), rgba(74, 108, 247, 0.05));
            margin: 12px -24px;
            padding: 16px 24px;
            border-radius: 8px;
            font-weight: 600;
            color: var(--primary);
            border-left: 4px solid var(--primary);
        }

        .spec-item i {
            width: 24px;
            height: 24px;
            margin-right: 14px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--primary);
            background: linear-gradient(135deg, rgba(74, 108, 247, 0.1), rgba(74, 108, 247, 0.2));
            border-radius: 6px;
            font-size: 14px;
        }

        .spec-item:hover {
            background-color: #f8fafc;
            padding-left: 8px;
        }

        /* 卡片底部 */
        .card-footer {
            padding: 24px;
            background: linear-gradient(to right, #f8fafc, #ffffff);
            border-top: 1px solid #f1f5f9;
            position: relative;
            overflow: hidden;
        }

        .card-footer::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 2px;
            background: linear-gradient(90deg, var(--primary), var(--secondary));
            opacity: 0;
            transition: opacity 0.3s ease;
        }

        .server-card:hover .card-footer::before {
            opacity: 1;
        }

        .pricing {
            display: flex;
            align-items: center;
            justify-content: space-between;
            margin-bottom: 20px;
            flex-wrap: wrap;
        }

        .current-price {
            display: flex;
            align-items: baseline;
        }

        .price {
            color: var(--danger);
            font-size: 32px;
            font-weight: 800;
            line-height: 1;
            text-shadow: 0 2px 4px rgba(239, 68, 68, 0.1);
        }

        .period {
            color: var(--gray);
            font-size: 15px;
            margin-left: 4px;
            font-weight: 500;
        }

        .original-price {
            color: var(--gray);
            font-size: 14px;
            font-weight: 500;
        }

        .original-price del {
            color: #94a3b8;
            margin-left: 6px;
            font-weight: 400;
        }

        .discount-badge {
            background: linear-gradient(135deg, #ef4444, #f87171);
            color: white;
            padding: 6px 14px;
            border-radius: 20px;
            font-size: 13px;
            font-weight: 700;
            box-shadow: 0 2px 8px rgba(239, 68, 68, 0.3);
        }

        /* 优化后的购买按钮 */
        .buy-btn {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 100%;
            padding: 18px 24px;
            background: linear-gradient(135deg, var(--primary), var(--primary-dark));
            color: white;
            text-decoration: none;
            border-radius: 10px;
            font-weight: 700;
            font-size: 17px;
            transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
            border: none;
            cursor: pointer;
            position: relative;
            overflow: hidden;
            letter-spacing: 0.5px;
            text-transform: uppercase;
            box-shadow: 0 6px 20px rgba(74, 108, 247, 0.3);
            transform: translateY(0);
        }

        .buy-btn:hover {
            background: linear-gradient(135deg, var(--primary-dark), #2a44d7);
            transform: translateY(-3px);
            box-shadow: 0 12px 25px rgba(74, 108, 247, 0.4);
            letter-spacing: 1px;
        }

        .buy-btn:active {
            transform: translateY(-1px);
            box-shadow: 0 4px 15px rgba(74, 108, 247, 0.3);
        }

        .buy-btn i {
            margin-right: 10px;
            font-size: 18px;
            transition: transform 0.3s ease;
        }

        .buy-btn:hover i {
            transform: translateX(4px) scale(1.1);
        }

        /* 按钮涟漪效果 */
        .buy-btn::after {
            content: '';
            position: absolute;
            top: 50%;
            left: 50%;
            width: 5px;
            height: 5px;
            background: rgba(255, 255, 255, 0.5);
            opacity: 0;
            border-radius: 100%;
            transform: scale(1, 1) translate(-50%);
            transform-origin: 50% 50%;
        }

        .buy-btn:focus:not(:active)::after {
            animation: ripple 1s ease-out;
        }

        @keyframes ripple {
            0% {
                transform: scale(0, 0);
                opacity: 0.5;
            }
            100% {
                transform: scale(40, 40);
                opacity: 0;
            }
        }

        /* 按钮加载状态 */
        .buy-btn.loading {
            position: relative;
            pointer-events: none;
            color: transparent;
        }

        .buy-btn.loading::before {
            content: '';
            position: absolute;
            left: 50%;
            top: 50%;
            width: 24px;
            height: 24px;
            border: 3px solid rgba(255, 255, 255, 0.3);
            border-top-color: white;
            border-radius: 50%;
            animation: spin 0.8s linear infinite;
            transform: translate(-50%, -50%);
        }

        @keyframes spin {
            to { transform: translate(-50%, -50%) rotate(360deg); }
        }

        /* 成功提示 */
        .buy-btn.success {
            background: linear-gradient(135deg, var(--secondary), #0ca678);
            pointer-events: none;
        }

        .buy-btn.success::after {
            content: '✓';
            position: absolute;
            left: 50%;
            top: 50%;
            transform: translate(-50%, -50%);
            font-size: 20px;
        }

        /* 区域标识 */
        .server-card[data-region="korea"] .server-title::before {
            content: "🇰🇷";
        }

        .server-card[data-region="usa"] .server-title::before {
            content: "🇺🇸";
        }

        /* 响应式设计 */
        @media (max-width: 768px) {
            .cloud-server-container {
                grid-template-columns: 1fr;
                padding: 10px;
                gap: 20px;
            }

            .server-card {
                margin-bottom: 0;
            }
        }

        @media (min-width: 769px) and (max-width: 1024px) {
            .cloud-server-container {
                grid-template-columns: repeat(2, 1fr);
            }
        }

        /* 卡片动画效果 */
        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .server-card {
            animation: fadeInUp 0.6s ease-out;
        }

        /* 悬停效果增强 */
        .server-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            right: 0;
            height: 3px;
            background: linear-gradient(90deg, var(--primary), var(--secondary));
            transform: scaleX(0);
            transform-origin: left;
            transition: transform 0.4s ease;
        }

        .server-card:hover::before {
            transform: scaleX(1);
        }

        /* 筛选和排序控件 */
        .controls {
            max-width: 1400px;
            margin: 100px auto 30px;
            display: flex;
            gap: 15px;
            flex-wrap: wrap;
            justify-content: center;
        }

        .filter-btn, .sort-btn {
            padding: 10px 20px;
            background: white;
            border: 2px solid #e2e8f0;
            border-radius: 8px;
            font-weight: 600;
            color: var(--dark);
            cursor: pointer;
            transition: all 0.3s ease;
        }

        .filter-btn:hover, .sort-btn:hover {
            border-color: var(--primary);
            color: var(--primary);
            transform: translateY(-2px);
        }

        .filter-btn.active, .sort-btn.active {
            background: var(--primary);
            border-color: var(--primary);
            color: white;
        }