@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+SC:wght@300;400;500;700&display=swap');
        
        :root {
            --primary-color: #1E88E5;
            --secondary-color: #4CAF50;
            --accent-color: #FFC107;
            --bg-color: #F5F5F5;
            --text-color: #333333;
            --text-light: #666666;
            --text-lighter: #999999;
        }
        
        body {
            font-family: 'Noto Sans SC', sans-serif;
            color: var(--text-color);
            background-color: var(--bg-color);
            scroll-behavior: smooth;
        }
        
        .btn-primary {
            background-color: var(--primary-color);
            color: white;
            transition: all 0.3s ease;
        }
        
        .btn-primary:hover {
            background-color: #1976D2;
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
        }
        
        .btn-secondary {
            background-color: var(--secondary-color);
            color: white;
            transition: all 0.3s ease;
        }
        
        .btn-secondary:hover {
            background-color: #388E3C;
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
        }
        
        .btn-accent {
            background-color: var(--accent-color);
            color: var(--text-color);
            transition: all 0.3s ease;
        }
        
        .btn-accent:hover {
            background-color: #FFB300;
            transform: translateY(-2px);
            box-shadow: 0 4px 8px rgba(0, 0, 0, 0.1);
        }
        
        .card {
            background-color: white;
            border-radius: 8px;
            box-shadow: 0 4px 6px rgba(0, 0, 0, 0.05);
            transition: all 0.3s ease;
        }
        
        .card:hover {
            box-shadow: 0 8px 15px rgba(0, 0, 0, 0.1);
            transform: translateY(-5px);
        }
        
        .nav-link {
            position: relative;
            transition: all 0.3s ease;
        }
        
        .nav-link::after {
            content: '';
            position: absolute;
            width: 0;
            height: 2px;
            bottom: -2px;
            left: 0;
            background-color: var(--primary-color);
            transition: width 0.3s ease;
        }
        
        .nav-link:hover::after,
        .nav-link.active::after {
            width: 100%;
        }
        
        .download-float-btn {
            position: fixed;
            bottom: 30px;
            right: 30px;
            z-index: 1000;
            background-color: var(--accent-color);
            color: var(--text-color);
            border-radius: 50px;
            padding: 12px 24px;
            font-weight: bold;
            box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
            transition: all 0.3s ease;
            display: flex;
            align-items: center;
            gap: 8px;
        }
        
        .download-float-btn:hover {
            transform: translateY(-3px);
            box-shadow: 0 6px 16px rgba(0, 0, 0, 0.2);
            background-color: #FFB300;
        }
        
        .modal {
            display: none;
            position: fixed;
            z-index: 2000;
            left: 0;
            top: 0;
            width: 100%;
            height: 100%;
            overflow: auto;
            background-color: rgba(0, 0, 0, 0.5);
            animation: fadeIn 0.3s ease;
        }
        
        .modal-content {
            background-color: white;
            margin: 10% auto;
            padding: 20px;
            border-radius: 8px;
            width: 80%;
            max-width: 500px;
            animation: slideIn 0.3s ease;
        }
        
        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }
        
        @keyframes slideIn {
            from { transform: translateY(-50px); opacity: 0; }
            to { transform: translateY(0); opacity: 1; }
        }
        
        .close {
            color: var(--text-lighter);
            float: right;
            font-size: 28px;
            font-weight: bold;
            cursor: pointer;
            transition: color 0.3s ease;
        }
        
        .close:hover {
            color: var(--text-color);
        }
        
        /* 响应式调整 */
        @media (max-width: 768px) {
            .download-float-btn {
                bottom: 20px;
                right: 20px;
                padding: 10px 20px;
                font-size: 14px;
            }
            
            .modal-content {
                margin: 20% auto;
                width: 90%;
            }
        }
        
        /* 自定义滚动条 */
        ::-webkit-scrollbar {
            width: 8px;
        }
        
        ::-webkit-scrollbar-track {
            background: #f1f1f1;
        }
        
        ::-webkit-scrollbar-thumb {
            background: var(--primary-color);
            border-radius: 4px;
        }
        
        ::-webkit-scrollbar-thumb:hover {
            background: #1976D2;
        }
        
        /* 高亮文本 */
        .highlight {
            color: var(--primary-color);
            font-weight: 500;
        }
        
        /* 分隔线 */
        .divider {
            height: 2px;
            background: linear-gradient(to right, transparent, var(--primary-color), transparent);
            margin: 2rem 0;
        }