:root {
            /* 使用base.css中的主色调作为logo颜色 */
            --primary-color: #1296db;
            --primary-hover: #0e7cb8;
            --primary-active: #0b6799;
            --primary-light: #e3f2fd;
            --primary-dark: #0d47a1;
            --secondary-color: #0d47a1;
            --accent-color: #4cc9f0;
            --success-color: #4caf50;
            --warning-color: #ff9800;
            --error-color: #f44336;
            --info-color: #2196f3;
            --border-radius: 12px;
            --box-shadow: 0 8px 30px rgba(0,0,0,0.08);
            --transition: all 0.3s ease;
        }
        
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            line-height: 1.6;
            color: #444;
            background: linear-gradient(135deg, #f5f7ff 0%, #e6f0ff 100%);
            overflow-x: hidden;
        }
        
        .container {
            width: 90%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 15px;
        }
        
        /* 头部样式 */
        header {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
            color: white;
            padding: 1.2rem 0;
            box-shadow: 0 4px 12px rgba(0,0,0,0.1);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        
        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .logo {
            display: flex;
            align-items: center;
            gap: 12px;
            font-size: 1.6rem;
            font-weight: 800;
        }
        
        .logo-img {
            width: 40px;
            height: 40px;
            background: #fff;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            color: var(--primary);
        }
        
        nav ul {
            display: flex;
            list-style: none;
            gap: 1.8rem;
        }
        
        nav a {
            color: white;
            text-decoration: none;
            font-weight: 500;
            padding: 8px 12px;
            border-radius: 30px;
            transition: var(--transition);
            font-size: 1rem;
            position: relative;
            overflow: hidden;
        }
        
        nav a:hover {
            background: rgba(255,255,255,0.2);
            transform: translateY(-2px);
        }
        
        nav a.active {
            background: rgba(255,255,255,0.3);
            font-weight: 600;
        }
        
        /* 英雄区域 */
        .hero {
            background: linear-gradient(rgba(18, 150, 219, 0.9), rgba(13, 71, 161, 0.85)), 
                linear-gradient(135deg, var(--primary-dark), var(--primary-color));
            color: white;
            text-align: center;
            padding: 5rem 2rem;
            margin-bottom: 3rem;
            border-radius: 0 0 var(--border-radius) var(--border-radius);
            position: relative;
            overflow: hidden;
        }
        
        .hero::before {
            content: '';
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: radial-gradient(circle at center, transparent 0%, rgba(0,0,0,0.3) 100%);
            z-index: 0;
        }
        
        .hero-content {
            position: relative;
            z-index: 2;
            max-width: 800px;
            margin: 0 auto;
        }
        
        .hero h1 {
            font-size: 3.2rem;
            margin-bottom: 1.5rem;
            text-shadow: 0 2px 4px rgba(0,0,0,0.2);
            font-weight: 800;
        }
        
        .hero p {
            font-size: 1.3rem;
            margin: 0 auto 2.5rem;
            opacity: 0.95;
            line-height: 1.8;
        }
        
        .cta-button {
            display: inline-block;
            background: white;
            color: var(--primary-color);
            padding: 14px 32px;
            border-radius: 50px;
            font-weight: 700;
            text-decoration: none;
            font-size: 1.1rem;
            transition: var(--transition);
            box-shadow: 0 4px 15px rgba(0,0,0,0.2);
            border: 2px solid transparent;
        }
        
        .cta-button:hover {
            transform: translateY(-5px);
            box-shadow: 0 8px 20px rgba(0,0,0,0.25);
            background: transparent;
            color: white;
            border-color: white;
        }
        
        /* 核心内容区域 */
        .section {
            background: white;
            border-radius: var(--border-radius);
            padding: 3.5rem 3rem;
            margin-bottom: 3rem;
            box-shadow: var(--box-shadow);
            position: relative;
        }
        
        .section-title {
            text-align: center;
            margin-bottom: 3rem;
            position: relative;
        }
        
        .section-title h2 {
            font-size: 2.5rem;
            color: var(--primary-dark);
            display: inline-block;
            padding-bottom: 15px;
            font-weight: 800;
        }
        
        .section-title h2:after {
            content: '';
            position: absolute;
            width: 80px;
            height: 4px;
            background: var(--accent-color);
            bottom: 0;
            left: 50%;
            transform: translateX(-50%);
            border-radius: 2px;
        }
        
        .intro-text {
            font-size: 1.2rem;
            text-align: center;
            max-width: 900px;
            margin: 0 auto 3rem;
            line-height: 1.8;
            color: #555;
        }
        
        /* 知识体系结构 */
        .knowledge-structure {
            display: flex;
            justify-content: space-between;
            margin-bottom: 4rem;
            gap: 25px;
        }
        
        .structure-item {
            flex: 1;
            text-align: center;
            padding: 2.2rem 1.5rem;
            border-radius: var(--border-radius);
            background: white;
            box-shadow: var(--box-shadow);
            transition: var(--transition);
            border-top: 4px solid var(--primary-color);
        }
        
        .structure-item:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 35px rgba(0,0,0,0.1);
        }
        
        .structure-icon {
            font-size: 3.2rem;
            margin-bottom: 1.5rem;
            color: var(--primary-color);
        }
        
        .structure-title {
            font-size: 1.7rem;
            margin-bottom: 1.2rem;
            color: var(--primary-dark);
            font-weight: 700;
        }
        
        .structure-desc {
            color: #666;
            margin-bottom: 1.5rem;
            font-size: 1.05rem;
        }
        
        /* 教程卡片 */
        .tutorial-cards {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
            gap: 30px;
            margin-top: 2rem;
        }
        
        .card {
            background: white;
            border-radius: var(--border-radius);
            overflow: hidden;
            box-shadow: var(--box-shadow);
            transition: var(--transition);
            border-left: 4px solid var(--primary-color);
        }
        
        .card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 35px rgba(0,0,0,0.1);
        }
        
        .card-header {
            background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
            color: white;
            padding: 1.6rem;
        }
        
        .card-header h3 {
            font-size: 1.6rem;
            margin-bottom: 0.5rem;
            font-weight: 700;
        }
        
        .card-body {
            padding: 1.8rem;
        }
        
        .card-body ul {
            list-style: none;
            padding-left: 0;
        }
        
        .card-body li {
            padding: 12px 0;
            border-bottom: 1px solid #f0f0f0;
            display: flex;
            align-items: flex-start;
        }
        
        .card-body li:last-child {
            border-bottom: none;
        }
        
        .card-body li i {
            color: var(--accent-color);
            margin-right: 12px;
            margin-top: 5px;
            min-width: 20px;
        }
        
        .card-detail {
            background: #f9faff;
            border-left: 3px solid var(--accent-color);
            padding: 1.5rem;
            margin-top: 1rem;
            border-radius: 8px;
        }
        
        .card-detail h4 {
            color: var(--primary-dark);
            margin-bottom: 0.8rem;
            font-size: 1.2rem;
        }
        
        .card-detail ul {
            padding-left: 20px;
        }
        
        .card-detail li {
            margin-bottom: 8px;
            color: #555;
            border-bottom: none;
            padding: 5px 0;
            position: relative;
        }
        
        .card-detail li:before {
            content: "•";
            color: var(--accent-color);
            font-weight: bold;
            position: absolute;
            left: -20px;
        }
        
        /* 学习流程 */
        .learning-steps {
            display: flex;
            flex-wrap: wrap;
            justify-content: center;
            gap: 30px;
            margin-top: 2rem;
        }
        
        .step {
            flex: 1;
            min-width: 250px;
            max-width: 300px;
            background: white;
            border-radius: var(--border-radius);
            padding: 2.2rem 1.8rem;
            box-shadow: var(--box-shadow);
            position: relative;
            border-top: 4px solid var(--success-color);
        }
        
        .step-number {
            position: absolute;
            top: -20px;
            left: 50%;
            transform: translateX(-50%);
            background: var(--success-color);
            color: white;
            width: 40px;
            height: 40px;
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            font-weight: bold;
            font-size: 1.2rem;
            box-shadow: 0 4px 10px rgba(76, 175, 80, 0.4);
        }
        
        .step h3 {
            color: var(--primary-dark);
            margin-bottom: 1rem;
            text-align: center;
            font-weight: 700;
        }
        
        .step p {
            text-align: center;
            color: #555;
        }
        
        /* 工具卡片 */
        .tools-container {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(400px, 1fr));
            gap: 30px;
            margin-top: 2rem;
        }
        
        .tool-card {
            background: white;
            border-radius: var(--border-radius);
            padding: 2rem;
            box-shadow: var(--box-shadow);
            border-top: 4px solid var(--warning-color);
            transition: var(--transition);
        }
        
        .tool-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 15px 35px rgba(0,0,0,0.1);
        }
        
        .tool-header {
            display: flex;
            align-items: center;
            justify-content: flex-start;
            gap: 0.8rem;
            margin-bottom: 1.5rem;
        }
        
        .tool-icon {
            font-size: 2.5rem;
            color: var(--warning-color);
            display: flex;
            align-items: center;
            height: 1em;
        }
        
        .tool-card h3 {
            font-size: 1.6rem;
            color: var(--primary-dark);
            margin: 0;
        }
        
        .tool-card ul {
            padding-left: 20px;
            margin-top: 1rem;
        }
        
        .tool-card li {
            margin-bottom: 10px;
            color: #555;
            position: relative;
        }
        
        .tool-card li:before {
            content: "•";
            color: var(--warning-color);
            font-weight: bold;
            position: absolute;
            left: -20px;
        }
        
        /* 二维码弹窗 */
        .modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.7);
            z-index: 2000;
            justify-content: center;
            align-items: center;
        }
        
        .modal-content {
            background: white;
            border-radius: var(--border-radius);
            padding: 2.5rem;
            text-align: center;
            max-width: 350px;
            box-shadow: 0 5px 30px rgba(0,0,0,0.3);
            position: relative;
            animation: modalIn 0.4s ease;
        }
        
        @keyframes modalIn {
            from { opacity: 0; transform: translateY(-50px); }
            to { opacity: 1; transform: translateY(0); }
        }
        
        .close-modal {
            position: absolute;
            top: 15px;
            right: 15px;
            font-size: 1.8rem;
            cursor: pointer;
            color: #999;
            transition: var(--transition);
        }
        
        .close-modal:hover {
            color: var(--primary-color);
        }
        
        .qrcode {
            width: 200px;
            height: 200px;
            background: #f5f5f5;
            margin: 20px auto;
            display: flex;
            justify-content: center;
            align-items: center;
            border-radius: 8px;
            position: relative;
            overflow: hidden;
        }
        
        .qrcode:before {
            content: "";
            position: absolute;
            width: 100%;
            height: 100%;
            background: 
                linear-gradient(135deg, transparent 0%, transparent 45%, var(--primary-color) 45%, var(--primary-color) 55%, transparent 55%, transparent 100%),
                linear-gradient(45deg, transparent 0%, transparent 45%, var(--primary-dark) 45%, var(--primary-dark) 55%, transparent 55%, transparent 100%);
            background-size: 20px 20px;
            opacity: 0.1;
        }
        
        .qrcode img {
            width: 180px;
            height: 180px;
            object-fit: contain;
        }
        
        .qrcode-placeholder {
            display: flex;
            flex-direction: column;
            align-items: center;
            justify-content: center;
            color: #666;
            font-size: 5rem;
        }
        
        .qrcode-placeholder i {
            font-size: 5rem;
            margin-bottom: 10px;
            color: var(--primary-color);
        }
        
        .modal-content h3 {
            color: var(--primary-dark);
            margin-bottom: 1rem;
            font-size: 1.5rem;
        }
        
        .modal-content p {
            color: #666;
            margin-top: 15px;
            font-size: 0.9rem;
        }
        
        /* 页脚 */
        footer {
            background: linear-gradient(135deg, #1a1a2e, #16213e);
            color: white;
            padding: 4rem 0 2rem;
            margin-top: 4rem;
        }
        
        .footer-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 40px;
            margin-bottom: 3rem;
        }
        
        .footer-column h3 {
            font-size: 1.4rem;
            margin-bottom: 1.5rem;
            position: relative;
            padding-bottom: 12px;
            font-weight: 600;
        }
        
        .footer-column h3:after {
            content: '';
            position: absolute;
            width: 50px;
            height: 3px;
            background: var(--accent-color);
            bottom: 0;
            left: 0;
        }
        
        .footer-column ul {
            list-style: none;
        }
        
        .footer-column ul li {
            margin-bottom: 12px;
            display: flex;
            align-items: center;
        }
        
        .footer-column ul li i {
            margin-right: 10px;
            color: var(--accent-color);
            width: 20px;
        }
        
        .footer-column a {
            color: #ccc;
            text-decoration: none;
            transition: var(--transition);
            display: flex;
            align-items: center;
            cursor: pointer;
        }
        
        /* 页脚底部版权信息的链接样式 */
        .copyright a {
            color: #fff;
            text-decoration: underline;
        }
        
        .copyright a:hover {
            color: var(--accent-color);
            padding-left: 0;
        }
        
        .footer-column a:hover {
            color: var(--accent-color);
            padding-left: 5px;
        }
        
        .copyright {
            text-align: center;
            padding-top: 2rem;
            border-top: 1px solid rgba(255,255,255,0.1);
            color: #aaa;
            font-size: 0.9rem;
        }
        
        /* 响应式设计 */
        @media (max-width: 992px) {
            .knowledge-structure {
                flex-direction: column;
                gap: 30px;
            }
            
            .hero h1 {
                font-size: 2.6rem;
            }
            
            .tutorial-cards, .tools-container {
                grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            }
        }
        
        @media (max-width: 768px) {
            .header-content {
                flex-direction: column;
                gap: 20px;
                text-align: center;
            }
            
            nav ul {
                flex-wrap: wrap;
                justify-content: center;
                gap: 12px;
            }
            
            .hero {
                padding: 4rem 1.5rem;
            }
            
            .hero h1 {
                font-size: 2.2rem;
            }
            
            .hero p {
                font-size: 1.1rem;
            }
            
            .section {
                padding: 2.5rem 1.8rem;
            }
            
            .section-title h2 {
                font-size: 2.2rem;
            }
            
            .learning-steps {
                gap: 40px;
            }
            
            .step {
                min-width: 100%;
            max-width: 100%;
            margin-bottom: 40px;
            position: relative;
            padding-top: 2rem;
            padding-bottom: 2rem;
            border-top: 4px solid var(--success-color);
            border-left: none;
            box-shadow: 0 8px 20px rgba(0,0,0,0.05);
            transition: all 0.3s ease;
            transform: none;
            min-height: 200px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            text-align: center;
            background: linear-gradient(145deg, #ffffff, #f0f0f0);
        }
            
            .step:hover {
                transform: scale(1.02);
                box-shadow: 0 12px 25px rgba(0,0,0,0.1);
            }
            
            .step-number {
                top: -25px;
                left: 50%;
                transform: translateX(-50%);
                width: 50px;
                height: 50px;
                font-size: 1.3rem;
                background: var(--success-color);
                box-shadow: 0 5px 15px rgba(76, 175, 80, 0.5);
                z-index: 10;
            }
            
            .step h3 {
                font-size: 1.5rem;
                margin-top: 15px;
                margin-bottom: 15px;
                color: var(--primary-dark);
                font-weight: 700;
                text-align: center;
            }
            
            .step p {
                font-size: 1.05rem;
                line-height: 1.6;
                color: #555;
                max-width: 90%;
                margin: 0 auto;
            }
            
            .tools-container {
                grid-template-columns: 1fr;
            }
            
            .modal-content {
                max-width: 90%;
                padding: 1.5rem;
            }
            
            .qrcode {
                width: 180px;
                height: 180px;
            }
        }
        
        /* 图标字体 */
        .icon {
            display: inline-block;
            font-style: normal;
            font-weight: normal;
            line-height: 1;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }
        
        .icon-tree:before { content: "🌳"; }
        .icon-branch:before { content: "🌿"; }
        .icon-seedling:before { content: "🌱"; }
        .icon-handshake:before { content: "🤝"; }
        .icon-briefcase:before { content: "💼"; }
        .icon-heart:before { content: "❤️"; }
        .icon-rocket:before { content: "🚀"; }
        .icon-brain:before { content: "🧠"; }
        .icon-comments:before { content: "💬"; }
        .icon-user:before { content: "👤"; }
        .icon-network:before { content: "🔗"; }
        .icon-search:before { content: "🔍"; }
        .icon-chart:before { content: "📈"; }
        .icon-comment-dots:before { content: "💭"; }
        .icon-clipboard:before { content: "📋"; }
        .icon-robot:before { content: "🤖"; }
        .icon-wechat:before { content: "💬"; }
        .icon-weibo:before { content: "📱"; }
        .icon-tools:before { content: "🛠️"; }
        .icon-check-circle:before { content: "✓"; font-weight: bold; color: var(--accent); }