:root {
            --primary: #6366f1;
            --primary-dark: #4f46e5;
            --secondary: #64748b;
            --success: #10b981;
            --error: #ef4444;
            --light: #f8fafc;
            --dark: #1e293b;
            --darker: #0f172a;
            --border: #e2e8f0;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Microsoft YaHei', sans-serif;
            line-height: 1.6;
            color: var(--dark);
            background: #f8fafc;
            min-height: 100vh;
        }
        
        .app-container {
            min-height: 100vh;
            display: flex;
            flex-direction: column;
        }
        
        /* 关键布局样式 */
        .navbar {
            background: rgba(255, 255, 255, 0.95);
            padding: 1rem 0;
            position: sticky;
            top: 0;
            z-index: 1000;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
            backdrop-filter: blur(10px);
        }
        
        .nav-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 1.5rem;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .logo {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--primary);
            text-decoration: none;
        }
        
        /* 响应式导航 */
        .nav-links {
            display: flex;
            list-style: none;
            gap: 1.5rem;
            align-items: center;
        }
        
        .nav-links a {
            text-decoration: none;
            color: var(--dark);
            font-weight: 500;
            transition: color 0.2s;
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        
        /* 主内容布局优化 */
        .main-content {
            flex: 1;
            padding: 1rem;
        }
        
        .dashboard {
            background: white;
            border-radius: 16px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            overflow: hidden;
            max-width: 1200px;
            margin: 0 auto;
            width: 100%;
            display: grid;
            grid-template-columns: 1.2fr 0.8fr;
            min-height: 600px;
        }
        
        /* 左侧功能卡片 - 图标和文字同行布局 */
        .features-grid {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 1rem;
            margin: 2rem 0;
        }
        
        .feature-card {
            background: white;
            padding: 1.25rem;
            border-radius: 12px;
            box-shadow: 0 2px 8px rgba(0,0,0,0.08);
            border-left: 3px solid var(--primary);
            display: flex;
            align-items: center;
            gap: 1rem;
            transition: transform 0.3s ease, box-shadow 0.3s ease;
        }
        
        .feature-card:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(0,0,0,0.12);
        }
        
        .feature-icon {
            font-size: 1.8rem;
            flex-shrink: 0;
            width: 40px;
            text-align: center;
        }
        
        .feature-content {
            flex: 1;
        }
        
        .feature-title {
            font-weight: 600;
            margin-bottom: 0.25rem;
            color: var(--darker);
            font-size: 1rem;
        }
        
        .feature-desc {
            font-size: 0.85rem;
            color: var(--secondary);
            line-height: 1.5;
        }
        
        /* 响应式设计优化 */
        @media (max-width: 1024px) {
            .dashboard {
                grid-template-columns: 1fr;
                max-width: 500px;
            }
            
            .features-grid {
                grid-template-columns: 1fr;
            }
            
            .feature-card {
                padding: 1rem;
            }
        }
        
        @media (max-width: 768px) {
            .nav-links {
                display: none;
            }
            
            .dashboard {
                margin: 0.5rem;
                min-height: auto;
            }
            
            .content-left, .content-right {
                padding: 1.5rem !important;
            }
        }
        
        /* 内容区域 */
        .content-left {
            padding: 3rem;
            background: #f8fafc;
            display: flex;
            flex-direction: column;
            justify-content: center;
        }
        
        .hero-title {
            font-size: 2.25rem;
            font-weight: 700;
            color: var(--darker);
            margin-bottom: 1rem;
            line-height: 1.2;
        }
        
        .hero-subtitle {
            font-size: 1.05rem;
            color: var(--secondary);
            margin-bottom: 2rem;
        }
        
        .stats {
            display: flex;
            gap: 2rem;
            margin-top: 2rem;
            flex-wrap: wrap;
        }
        
        .stat-item {
            text-align: center;
            min-width: 80px;
        }
        
        .stat-number {
            font-size: 1.5rem;
            font-weight: 700;
            color: var(--primary);
            display: block;
        }
        
        .stat-label {
            font-size: 0.8rem;
            color: var(--secondary);
        }
        
        /* 右侧生成器 */
        .content-right {
            padding: 3rem;
            background: white;
            display: flex;
            flex-direction: column;
        }
        
        .generator-header {
            text-align: center;
            margin-bottom: 2rem;
        }
        
        .generator-title {
            font-size: 1.5rem;
            font-weight: 600;
            color: var(--darker);
            margin-bottom: 0.5rem;
        }
        
        .generator-subtitle {
            color: var(--secondary);
            font-size: 0.95rem;
        }
        
        /* 表单样式 */
        .form-group {
            margin-bottom: 1.5rem;
        }
        
        .form-label {
            display: block;
            margin-bottom: 0.5rem;
            font-weight: 500;
            color: var(--darker);
            display: flex;
            align-items: center;
            gap: 0.5rem;
        }
        
        .form-input {
            width: 100%;
            padding: 1rem;
            border: 1px solid var(--border);
            border-radius: 8px;
            font-size: 1rem;
            transition: all 0.2s;
            background: white;
        }
        
        .form-input:focus {
            outline: none;
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
        }
        
        .url-prefix {
            display: flex;
            align-items: center;
            gap: 0.5rem;
            margin-bottom: 0.5rem;
            font-weight: 500;
            color: var(--primary);
        }
        
        /* 按钮样式 */
        .btn {
            padding: 0.75rem 1.5rem;
            border-radius: 8px;
            text-decoration: none;
            font-weight: 500;
            transition: all 0.2s;
            border: none;
            cursor: pointer;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
            font-size: 0.95rem;
        }
        
        .btn-primary {
            background: var(--primary);
            color: white;
            border: 1px solid var(--primary);
        }
        
        .btn-primary:hover:not(:disabled) {
            background: var(--primary-dark);
            transform: translateY(-1px);
        }
        
        .btn-primary:disabled {
            opacity: 0.6;
            cursor: not-allowed;
        }
        
        .btn-outline {
            background: transparent;
            color: var(--primary);
            border: 1px solid var(--primary);
        }
        
        .btn-outline:hover {
            background: var(--primary);
            color: white;
        }
        
        /* 消息提示 */
        .alert {
            padding: 1rem;
            border-radius: 8px;
            margin-bottom: 1rem;
            font-weight: 500;
            animation: slideIn 0.3s ease;
        }
        
        @keyframes slideIn {
            from {
                opacity: 0;
                transform: translateY(-10px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }
        
        .alert.success {
            background: #ecfdf5;
            color: #065f46;
            border: 1px solid #a7f3d0;
        }
        
        .alert.error {
            background: #fef2f2;
            color: #991b1b;
            border: 1px solid #fecaca;
        }
        
        /* 结果卡片 */
        .result-card {
            background: #f8fafc;
            border-radius: 12px;
            padding: 1.5rem;
            margin-top: 1rem;
            border: 1px solid var(--border);
            animation: fadeIn 0.5s ease;
        }
        
        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }
        
        .short-url-display {
            display: flex;
            gap: 0.75rem;
            margin: 1rem 0;
        }
        
        .short-url-input {
            flex: 1;
            padding: 0.75rem;
            border: 1px solid var(--border);
            border-radius: 6px;
            background: white;
            font-family: 'Courier New', monospace;
            font-size: 0.9rem;
            overflow: hidden;
            text-overflow: ellipsis;
        }
        
        .action-buttons {
            display: flex;
            gap: 0.75rem;
            margin: 1rem 0;
        }
        
        .action-buttons .btn {
            flex: 1;
        }
        
        /* 二维码区域 */
        .qr-section {
            text-align: center;
            margin-top: 1.5rem;
            padding-top: 1.5rem;
            border-top: 1px solid var(--border);
        }
        
        .qr-title {
            font-weight: 600;
            margin-bottom: 1rem;
            color: var(--darker);
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 0.5rem;
        }
        
        .qr-code {
            border-radius: 8px;
            width: 150px;
            height: 150px;
            display: block;
            margin: 0 auto;
            border: 1px solid var(--border);
            background: white;
            padding: 5px;
        }
        
        .qr-download-btn {
            margin-top: 1rem;
            background: var(--success);
            color: white;
            width: 100%;
        }
        
        .qr-download-btn:hover {
            background: #0da271;
        }
        
        /* 升级卡片 */
        .upgrade-card {
            background: linear-gradient(135deg, #f0f9ff 0%, #e0f2fe 100%);
            padding: 1.5rem;
            border-radius: 12px;
            margin-top: 1.5rem;
            text-align: center;
            border: 1px solid #bae6fd;
            animation: pulse 2s infinite;
        }
        
        @keyframes pulse {
            0% { box-shadow: 0 0 0 0 rgba(99, 102, 241, 0.2); }
            70% { box-shadow: 0 0 0 10px rgba(99, 102, 241, 0); }
            100% { box-shadow: 0 0 0 0 rgba(99, 102, 241, 0); }
        }
        
        /* 页脚优化 */
        .footer {
            background: var(--darker);
            color: white;
            padding: 2rem 0 1rem;
            margin-top: auto;
        }
        
        .footer-content {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 1.5rem;
            display: grid;
            grid-template-columns: 2fr 1fr 1fr;
            gap: 2rem;
        }
        
        .footer-section h3 {
            margin-bottom: 1rem;
            color: white;
            font-size: 1.1rem;
        }
        
        .footer-links {
            list-style: none;
        }
        
        .footer-links li {
            margin-bottom: 0.5rem;
        }
        
        .footer-links a {
            color: #cbd5e1;
            text-decoration: none;
            transition: color 0.2s;
            display: flex;
            align-items: center;
            gap: 0.5rem;
            font-size: 0.9rem;
        }
        
        .footer-links a:hover {
            color: white;
        }
        
        .copyright {
            text-align: center;
            padding-top: 1.5rem;
            margin-top: 1.5rem;
            border-top: 1px solid #374151;
            color: #9ca3af;
            font-size: 0.85rem;
        }
        
        /* 加载优化 - 延迟加载非关键CSS */
        .non-critical {
            display: none;
        }
        
        /* 移动端优化 */
        @media (max-width: 640px) {
            .hero-title {
                font-size: 1.75rem;
            }
            
            .short-url-display {
                flex-direction: column;
            }
            
            .action-buttons {
                flex-direction: column;
            }
            
            .footer-content {
                grid-template-columns: 1fr;
                text-align: center;
                gap: 1.5rem;
            }
            
            .stats {
                justify-content: space-around;
            }
            
            .stat-item {
                min-width: 70px;
            }
        }