:root {
            --primary-white: #ffffff;
            --secondary-white: #f8f9fa;
            --light-gray: #f1f3f5;
            --medium-gray: #e9ecef;
            --dark-gray: #6c757d;
            --text-dark: #212529;
            --text-medium: #495057;
            --text-light: #868e96;
            
            --accent-blue: #1a73e8;
            --accent-light-blue: #4285f4;
            --accent-cyan: #00bcd4;
            --accent-gradient: linear-gradient(135deg, #1a73e8 0%, #4285f4 100%);
            --accent-light-gradient: linear-gradient(135deg, #e3f2fd 0%, #f3f8ff 100%);
            
            --shadow-light: 0 5px 15px rgba(0, 0, 0, 0.05);
            --shadow-medium: 0 10px 25px rgba(0, 0, 0, 0.1);
            --shadow-hover: 0 15px 35px rgba(26, 115, 232, 0.15);
            --border-radius: 12px;
            --transition: all 0.3s ease;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Microsoft YaHei', sans-serif;
        }
        
        body {
            background-color: var(--primary-white);
            color: var(--text-dark);
            line-height: 1.6;
            overflow-x: hidden;
        }
		.logo-text {
			background: var(--gradient-accent);
			-webkit-background-clip: text;
			background-clip: text;
		}
		.logo img {
		max-height: 45px;
		margin-right: 15px;
	}
        
        .container {
            width: 100%;
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        /* 头部导航 - 响应式设计 */
        header {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background: var(--primary-white);
            z-index: 1000;
            box-shadow: var(--shadow-light);
            padding: 15px 0;
            transition: var(--transition);
        }
        
        .header-container {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .logo {
            display: flex;
            align-items: center;
            font-size: 1.8rem;
            font-weight: 700;
            z-index: 1001;
        }
        
        .logo i {
            margin-right: 12px;
            color: var(--accent-blue);
            font-size: 2rem;
        }
        
        /* 桌面端导航菜单 */
        .desktop-nav {
            display: flex;
            align-items: center;
        }
        
        .desktop-nav ul {
            display: flex;
            list-style: none;
            gap: 40px;
            margin-right: 30px;
        }
        
        .desktop-nav ul li {
            position: relative;
        }
        
        .nav-link {
            text-decoration: none;
            color: var(--text-dark);
            font-weight: 500;
            padding: 8px 0;
            position: relative;
            transition: var(--transition);
            font-size: 1.05rem;
        }
        
        .nav-link::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--accent-gradient);
            transition: var(--transition);
            border-radius: 1px;
        }
        
        .nav-link:hover {
            color: var(--accent-blue);
        }
        
        .nav-link:hover::after {
            width: 100%;
        }
        
        .nav-link.active {
            color: var(--accent-blue);
        }
        
        .nav-link.active::after {
            width: 100%;
        }
        
        /* 移动端菜单按钮 */
        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            font-size: 1.5rem;
            color: var(--accent-blue);
            cursor: pointer;
            padding: 5px;
            z-index: 1001;
        }
        
        /* 移动端导航菜单 */
        .mobile-nav {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100vh;
            background: var(--primary-white);
            z-index: 999;
            padding: 80px 20px 20px;
            transform: translateX(-100%);
            transition: transform 0.3s ease;
            overflow-y: auto;
        }
        
        .mobile-nav.active {
            transform: translateX(0);
        }
        
        .mobile-nav ul {
            list-style: none;
        }
        
        .mobile-nav ul li {
            margin-bottom: 20px;
        }
        
        .mobile-nav .nav-link {
            display: block;
            padding: 15px 0;
            font-size: 1.2rem;
            border-bottom: 1px solid var(--light-gray);
        }
        
        .mobile-nav .nav-link.active {
            color: var(--accent-blue);
            border-bottom: 2px solid var(--accent-blue);
        }
        
        /* 语言切换和登录按钮 */
        .header-right {
            display: flex;
            align-items: center;
            gap: 20px;
        }
        
        .language-switcher {
            position: relative;
        }
        
        .language-btn {
            background: var(--light-gray);
            border: 1px solid var(--medium-gray);
            border-radius: 20px;
            padding: 8px 16px;
            cursor: pointer;
            display: flex;
            align-items: center;
            transition: var(--transition);
            font-weight: 500;
            color: var(--text-dark);
        }
        
        .language-btn:hover {
            background: var(--medium-gray);
            border-color: var(--accent-blue);
        }
        
        .language-btn i {
            margin-right: 8px;
            color: var(--accent-blue);
            font-size: 1rem;
        }
        
        .language-options {
            position: absolute;
            top: 100%;
            right: 0;
            background: var(--primary-white);
            box-shadow: var(--shadow-medium);
            border-radius: var(--border-radius);
            width: 120px;
            display: none;
            z-index: 10;
            overflow: hidden;
            border: 1px solid var(--medium-gray);
        }
        
        .language-options.show {
            display: block;
            animation: fadeIn 0.3s ease;
        }
        
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(-10px); }
            to { opacity: 1; transform: translateY(0); }
        }
        
        .language-option {
            padding: 10px 16px;
            cursor: pointer;
            transition: var(--transition);
            font-weight: 500;
            border-bottom: 1px solid var(--light-gray);
            color: var(--text-dark);
        }
        
        .language-option:last-child {
            border-bottom: none;
        }
        
        .language-option:hover {
            background: var(--light-gray);
            color: var(--accent-blue);
        }
        
        .auth-buttons {
            display: flex;
            gap: 15px;
        }
        
        .btn {
            padding: 10px 24px;
            border-radius: 25px;
            font-weight: 500;
            cursor: pointer;
            transition: var(--transition);
            border: none;
            text-decoration: none;
            display: inline-block;
            text-align: center;
            font-size: 1rem;
            position: relative;
            overflow: hidden;
        }
        
        .btn-login {
            background: transparent;
            color: var(--accent-blue);
            border: 1px solid var(--accent-blue);
        }
        
        .btn-login:hover {
            background: var(--light-gray);
            transform: translateY(-2px);
            box-shadow: var(--shadow-light);
        }
        
        .btn-register {
            background: var(--accent-gradient);
            color: white;
            box-shadow: var(--shadow-light);
        }
        
        .btn-register:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-medium);
        }
        
        /* 主要内容区域 */
        main {
            position: relative;
            margin-top: 80px;
        }
        
        section {
            padding: 80px 0;
            position: relative;
        }
        
        /* 英雄区域 */
        .hero {
            display: flex;
            align-items: center;
            justify-content: space-between;
            gap: 60px;
            padding: 40px 0 80px;
        }
        
        .hero-content {
            flex: 1;
            max-width: 600px;
        }
        
        .hero-badge {
            display: inline-block;
            background: var(--accent-light-gradient);
            color: var(--accent-blue);
            padding: 8px 20px;
            border-radius: 20px;
            font-weight: 600;
            margin-bottom: 25px;
            border: 1px solid rgba(26, 115, 232, 0.2);
            font-size: 0.9rem;
        }
        
      .hero-title {
		font-size: 4rem;
		font-weight: 900;
		line-height: 1.1;
		margin-bottom: 30px;
		background: linear-gradient(90deg, #ffffff, var(--accent-cyan));
		-webkit-background-clip: text;
		background-clip: text;
	}
        
        .hero-title span {
            color: var(--accent-blue);
        }
        
        .hero-description {
            font-size: 1.1rem;
            color: var(--text-medium);
            margin-bottom: 40px;
            line-height: 1.7;
        }
        
        .hero-buttons {
            display: flex;
            gap: 20px;
            flex-wrap: wrap;
        }
        
        .btn-hero {
            padding: 14px 32px;
            font-size: 1.1rem;
            font-weight: 600;
            border-radius: 30px;
        }
        
        .btn-primary {
            background: var(--accent-gradient);
            color: white;
            box-shadow: 0 5px 20px rgba(26, 115, 232, 0.2);
        }
        
        .btn-primary:hover {
            transform: translateY(-3px);
            box-shadow: 0 10px 30px rgba(26, 115, 232, 0.3);
        }
        
        .btn-secondary {
            background: transparent;
            color: var(--accent-blue);
            border: 1px solid var(--accent-blue);
        }
        
        .btn-secondary:hover {
            background: var(--light-gray);
            transform: translateY(-3px);
        }
        
        .hero-visual {
            flex: 1;
            position: relative;
        }
        
        .floating-cards {
            position: relative;
            width: 100%;
            height: 350px;
        }
        
        .floating-card {
            position: absolute;
            background: var(--primary-white);
            border-radius: var(--border-radius);
            padding: 25px;
            box-shadow: var(--shadow-medium);
            border: 1px solid var(--medium-gray);
            width: 250px;
            transition: var(--transition);
            animation: float 6s ease-in-out infinite;
        }
        
        .floating-card:nth-child(1) {
            top: 0;
            left: 0;
            animation-delay: 0s;
        }
        
        .floating-card:nth-child(2) {
            top: 6px;
            right: 0;
            animation-delay: 1s;
        }
        
        .floating-card:nth-child(3) {
            bottom: -20px;
            left: 30%;
            animation-delay: 2s;
        }
        
        @keyframes float {
            0%, 100% { transform: translateY(0) translateX(0); }
            50% { transform: translateY(-15px) translateX(5px); }
        }
        
        .floating-card:hover {
            transform: translateY(-10px) !important;
            box-shadow: var(--shadow-hover);
            border-color: rgba(26, 115, 232, 0.3);
        }
        
        .card-icon {
            font-size: 2.2rem;
            color: var(--accent-blue);
            margin-bottom: 20px;
        }
        
        .floating-card h3 {
            font-size: 1.3rem;
            font-weight: 700;
            margin-bottom: 10px;
            color: var(--text-dark);
        }
        
        .floating-card p {
            color: var(--text-medium);
            font-size: 0.95rem;
        }
        
        /* 功能区域 */
        .section-header {
            text-align: center;
            margin-bottom: 60px;
        }
        
        .section-subtitle {
            color: var(--accent-blue);
            font-weight: 600;
            font-size: 1rem;
            letter-spacing: 1px;
            text-transform: uppercase;
            margin-bottom: 15px;
        }
        
    .section-title {
		font-size: 3.5rem;
		font-weight: 900;
		line-height: 1.1;
		margin-bottom: 30px;
		background: linear-gradient(90deg, #ffffff, var(--accent-cyan));
		-webkit-background-clip: text;
		background-clip: text;
	}
        
        .section-description {
            font-size: 1.1rem;
            color: var(--text-medium);
            max-width: 700px;
            margin: 0 auto;
            line-height: 1.7;
        }
        
        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
            gap: 30px;
        }
        
        .feature-card {
            background: var(--primary-white);
            border-radius: var(--border-radius);
            padding: 35px;
            box-shadow: var(--shadow-medium);
            border: 1px solid var(--medium-gray);
            transition: var(--transition);
            position: relative;
            overflow: hidden;
        }
        
        .feature-card::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 4px;
            height: 100%;
            background: var(--accent-gradient);
        }
        
        .feature-card:hover {
            transform: translateY(-10px);
            box-shadow: var(--shadow-hover);
            border-color: rgba(26, 115, 232, 0.3);
        }
        
        .feature-icon {
            font-size: 2.2rem;
            color: var(--accent-blue);
            margin-bottom: 20px;
        }
        
        .feature-title {
            font-size: 1.4rem;
            font-weight: 700;
            margin-bottom: 15px;
            color: var(--text-dark);
        }
        
        .feature-description {
            color: var(--text-medium);
            line-height: 1.7;
            margin-bottom: 20px;
        }
        
        .feature-list {
            list-style: none;
        }
        
        .feature-list li {
            padding: 8px 0;
            color: var(--text-medium);
            position: relative;
            padding-left: 25px;
        }
        
        .feature-list li::before {
            content: '✓';
            position: absolute;
            left: 0;
            color: var(--accent-blue);
            font-weight: bold;
        }
        
        /* 产品区域 */
        .question-types {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
            gap: 20px;
            margin-bottom: 50px;
        }
        
        .type-item {
            background: var(--primary-white);
            padding: 25px;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow-light);
            transition: var(--transition);
            border: 1px solid var(--medium-gray);
            position: relative;
            overflow: hidden;
        }
        
        .type-item:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-medium);
            border-color: rgba(26, 115, 232, 0.3);
        }
        
        .type-item::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(45deg, transparent, rgba(26, 115, 232, 0.03), transparent);
        }
        
        .type-title {
            font-size: 1.2rem;
            font-weight: 700;
            margin-bottom: 8px;
            color: var(--text-dark);
        }
        
        .type-description {
            color: var(--text-medium);
            font-size: 0.9rem;
        }
        
        .platform-features {
            margin-top: 60px;
        }
        
        .features-list {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(330px, 1fr));
            gap: 25px;
        }
        
        .platform-feature {
            background: var(--primary-white);
            padding: 25px;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow-light);
            transition: var(--transition);
            border: 1px solid var(--medium-gray);
            display: flex;
            align-items: flex-start;
            gap: 20px;
        }
        
        .platform-feature:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-medium);
            border-color: rgba(26, 115, 232, 0.3);
        }
        
        .feature-icon-small {
            font-size: 1.6rem;
            color: var(--accent-blue);
            flex-shrink: 0;
        }
        
        .feature-content h4 {
            font-size: 1.2rem;
            font-weight: 700;
            margin-bottom: 10px;
            color: var(--text-dark);
        }
        
        .feature-content p {
            color: var(--text-medium);
            line-height: 1.6;
            font-size: 0.95rem;
        }
        
        /* 关于我们区域 */
        .about-content {
            display: grid;
            grid-template-columns: 1fr 1fr;
            gap: 60px;
            align-items: center;
        }
        
        .about-text h2 {
            font-size: 2.2rem;
            font-weight: 800;
            margin-bottom: 25px;
            color: var(--text-dark);
        }
        
        .about-text p {
            margin-bottom: 20px;
            color: var(--text-medium);
            line-height: 1.7;
        }
        
        .stats-grid {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 25px;
            margin-top: 40px;
        }
        
        .stat-item {
            text-align: center;
            padding: 25px;
            background: var(--primary-white);
            border-radius: var(--border-radius);
            box-shadow: var(--shadow-light);
            border: 1px solid var(--medium-gray);
            transition: var(--transition);
        }
        
        .stat-item:hover {
            transform: translateY(-5px);
            box-shadow: var(--shadow-medium);
            border-color: rgba(26, 115, 232, 0.3);
        }
        
        .stat-number {
            font-size: 2.2rem;
            font-weight: 800;
            color: var(--accent-blue);
            margin-bottom: 8px;
        }
        
        .stat-text {
            color: var(--text-medium);
            font-weight: 600;
            font-size: 0.95rem;
        }
        
        /* 联系我们页面 */
        .contact-page {
            display: none;
            padding: 100px 0 80px;
        }
        
        .contact-page.active {
            display: block;
        }
        
        /* 登录/注册页面 */
        .auth-page {
            display: none;
            padding: 100px 0 80px;
        }
        
        .auth-page.active {
            display: block;
        }
        
        .auth-box {
            background: var(--primary-white);
            width: 100%;
            max-width: 450px;
            margin: 0 auto;
            padding: 40px;
            border-radius: var(--border-radius);
            box-shadow: var(--shadow-medium);
            border: 1px solid var(--medium-gray);
        }
        
        .auth-title {
            text-align: center;
            margin-bottom: 30px;
            color: var(--text-dark);
            font-size: 2rem;
            font-weight: 700;
        }
        
        .auth-tabs {
            display: flex;
            margin-bottom: 30px;
            border-bottom: 2px solid var(--light-gray);
        }
        
        .auth-tab {
            flex: 1;
            text-align: center;
            padding: 15px;
            cursor: pointer;
            font-weight: 600;
            color: var(--text-medium);
            transition: var(--transition);
            position: relative;
        }
        
        .auth-tab.active {
            color: var(--accent-blue);
        }
        
        .auth-tab.active::after {
            content: '';
            position: absolute;
            bottom: -2px;
            left: 0;
            width: 100%;
            height: 3px;
            background: var(--accent-gradient);
            border-radius: 3px 3px 0 0;
        }
        
        .auth-form {
            display: none;
        }
        
        .auth-form.active {
            display: block;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
            color: var(--text-dark);
        }
        
        .form-group input,
        .form-group textarea,
        .form-group select {
            width: 100%;
            padding: 12px 16px;
            border: 1px solid var(--medium-gray);
            border-radius: 8px;
            font-size: 1rem;
            transition: var(--transition);
            background: var(--primary-white);
            color: var(--text-dark);
        }
        
        .form-group input:focus,
        .form-group textarea:focus,
        .form-group select:focus {
            outline: none;
            border-color: var(--accent-blue);
            box-shadow: 0 0 0 3px rgba(26, 115, 232, 0.1);
        }
        
        .btn-submit {
            background: var(--accent-gradient);
            color: white;
            width: 100%;
            padding: 14px;
            font-size: 1.1rem;
            font-weight: 600;
            border-radius: 8px;
            margin-top: 10px;
        }
        
        .btn-submit:hover {
            transform: translateY(-2px);
            box-shadow: var(--shadow-medium);
        }
        
        .social-login {
            text-align: center;
            margin-top: 30px;
            padding-top: 30px;
            border-top: 1px solid var(--light-gray);
        }
        
        .social-buttons {
            display: flex;
            justify-content: center;
            gap: 15px;
            margin-top: 20px;
        }
        
        .social-btn {
            display: flex;
            align-items: center;
            justify-content: center;
            width: 50px;
            height: 50px;
            border-radius: 50%;
            background: var(--light-gray);
            color: var(--text-dark);
            font-size: 1.2rem;
            transition: var(--transition);
            text-decoration: none;
        }
        
        .social-btn:hover {
            background: var(--accent-blue);
            color: white;
            transform: translateY(-3px);
        }
        
        /* 页脚 */
        footer {
            background: var(--secondary-white);
            padding: 60px 0 30px;
            border-top: 1px solid var(--medium-gray);
        }
        
        .footer-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 40px;
            margin-bottom: 50px;
        }
        
        .footer-section h3 {
            margin-bottom: 20px;
            font-size: 1.3rem;
            font-weight: 700;
            color: var(--text-dark);
            position: relative;
            padding-bottom: 15px;
        }
        
        .footer-section h3::after {
            content: '';
            position: absolute;
            bottom: 0;
            left: 0;
            width: 40px;
            height: 3px;
            background: var(--accent-gradient);
            border-radius: 3px;
        }
        
        .footer-section p {
            color: var(--text-medium);
            line-height: 1.7;
            font-size: 0.95rem;
        }
        
        .footer-section ul {
            list-style: none;
        }
        
        .footer-section ul li {
            margin-bottom: 12px;
        }
        
        .footer-section ul li a {
            color: var(--text-medium);
            text-decoration: none;
            transition: var(--transition);
            display: flex;
            align-items: center;
            font-size: 0.95rem;
        }
        
        .footer-section ul li a:hover {
            color: var(--accent-blue);
            transform: translateX(5px);
        }
        
        .footer-section ul li i {
            margin-right: 12px;
            color: var(--accent-blue);
            width: 20px;
        }
        
        .copyright {
            text-align: center;
            padding-top: 30px;
            border-top: 1px solid var(--medium-gray);
            color: var(--text-light);
            font-size: 0.9rem;
        }
        
        /* 响应式设计 - 重点优化移动端 */
        @media (max-width: 992px) {
            .desktop-nav {
                display: none;
            }
            
            .mobile-menu-btn {
                display: block;
            }
            
            .header-right .auth-buttons {
                display: none;
            }
            
            .mobile-nav .auth-buttons {
                display: flex;
                flex-direction: column;
                gap: 15px;
                margin-top: 30px;
                padding-top: 30px;
                border-top: 1px solid var(--light-gray);
            }
            
            .mobile-nav .auth-buttons .btn {
                width: 100%;
            }
            
            .mobile-nav .language-switcher {
                margin-top: 20px;
                display: block;
            }
            
            .hero {
                flex-direction: column;
                text-align: center;
                gap: 50px;
            }
            
            .hero-title {
                font-size: 2.5rem;
            }
            
            .section-title {
                font-size: 2.2rem;
            }
            
            .features-grid {
                grid-template-columns: 1fr;
            }
            
            .question-types {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .features-list {
                grid-template-columns: 1fr;
            }
            
            .about-content {
                grid-template-columns: 1fr;
                gap: 50px;
            }
            
            .floating-cards {
                height: 300px;
            }
            
            .floating-card {
                width: 220px;
                padding: 20px;
            }
        }
        
        @media (max-width: 768px) {
            .hero-title {
                font-size: 2.2rem;
            }
            
            .section-title {
                font-size: 2rem;
            }
            
            .question-types {
                grid-template-columns: 1fr;
            }
            
            .stats-grid {
                grid-template-columns: 1fr;
                gap: 20px;
            }
            
            .floating-cards {
                height: 250px;
            }
            
            .floating-card {
                width: 200px;
                padding: 18px;
            }
            
            section {
                padding: 60px 0;
            }
            
            .hero {
                padding: 30px 0 60px;
            }
        }
        
        @media (max-width: 480px) {
            .hero-title {
                font-size: 1.8rem;
            }
            
            .section-title {
                font-size: 1.8rem;
            }
            
            .btn-hero {
                padding: 12px 30px;
                font-size: 1rem;
                width: 100%;
            }
            
            .hero-buttons {
                flex-direction: column;
            }
            
            .feature-card, .platform-feature {
                padding: 25px 20px;
            }
            
            .auth-box {
                padding: 30px 20px;
            }
            
            .floating-cards {
                height: 220px;
            }
            
            .floating-card {
                width: 180px;
                padding: 15px;
            }
            
            .floating-card h3 {
                font-size: 1.2rem;
            }
            
            .card-icon {
                font-size: 1.8rem;
            }
        }
        
        /* 滚动动画 */
        .fade-in {
            opacity: 0;
            transform: translateY(30px);
            transition: opacity 0.8s ease, transform 0.8s ease;
        }
        
        .fade-in.visible {
            opacity: 1;
            transform: translateY(0);
        }
        
        .staggered-item {
            opacity: 0;
            transform: translateY(20px);
            transition: opacity 0.6s ease, transform 0.6s ease;
        }
        
        .staggered-item.visible {
            opacity: 1;
            transform: translateY(0);
        }