:root {
            --primary-color: #00d9ff;
            --secondary-color: #8a2be2;
            --accent-color: #ff2a6d;
            --dark-bg: #0a0e17;
            --darker-bg: #050811;
            --card-bg: rgba(10, 14, 23, 0.85);
            --text-light: #ffffff;
            --text-dim: #a0b1c5;
        }
        
        a {
            color: inherit;
            text-decoration: none;
            cursor: pointer;
            transition: all 0.3s ease;
            padding: 0.2em 0;
        }
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        
        body {
            font-family: 'Exo 2', sans-serif;
            background-color: var(--darker-bg);
            color: var(--text-light);
            line-height: 1.6;
            overflow-x: hidden;
            min-height: 100vh;
            background-image: 
                radial-gradient(circle at 5% 10%, rgba(0, 217, 255, 0.03) 0%, transparent 20%),
                radial-gradient(circle at 95% 90%, rgba(138, 43, 226, 0.03) 0%, transparent 20%),
                radial-gradient(circle at 50% 50%, rgba(255, 42, 109, 0.02) 0%, transparent 30%);
            padding-top: 80px; /* 为固定导航栏留出空间 */
        }
        
        .container {
            max-width: 1300px;
            margin: 0 auto;
            padding: 0 20px;
        }
        
        /* 导航栏样式 */
        .main-nav {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            background: rgba(5, 8, 17, 0.95);
            backdrop-filter: blur(10px);
            border-bottom: 1px solid rgba(0, 217, 255, 0.1);
            z-index: 1000;
            padding: 15px 0;
            transition: all 0.3s ease;
        }
        
        .main-nav.scrolled {
            background: rgba(5, 8, 17, 0.98);
            box-shadow: 0 5px 20px rgba(0, 0, 0, 0.3);
        }
        
        .nav-container {
            max-width: 1300px;
            margin: 0 auto;
            padding: 0 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }
        
        .nav-logo {
            display: flex;
            align-items: center;
            gap: 15px;
            text-decoration: none;
        }
        
        .nav-logo-icon {
            width: 40px;
            height: 40px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            border-radius: 50%;
            display: flex;
            align-items: center;
            justify-content: center;
            color: white;
            font-size: 18px;
        }
        
        .nav-logo-text {
            font-family: 'Orbitron', sans-serif;
            font-weight: 700;
            font-size: 20px;
            background: linear-gradient(to right, var(--primary-color), var(--accent-color));
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
        }
        
        .nav-menu {
            display: flex;
            list-style: none;
            gap: 30px;
        }
        
        .nav-item {
            position: relative;
        }
        
        .nav-link {
            color: var(--text-light);
            text-decoration: none;
            font-weight: 600;
            font-size: 16px;
            padding: 10px 0;
            transition: all 0.3s ease;
            position: relative;
        }
        
        .nav-link:hover {
            color: var(--primary-color);
        }
        
        .nav-link.active {
            color: var(--primary-color);
        }
        
        .nav-link.active::after {
            content: '';
            position: absolute;
            bottom: -5px;
            left: 0;
            width: 100%;
            height: 2px;
            background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
            border-radius: 2px;
        }
        
        /* 移动端菜单按钮 */
        .mobile-menu-btn {
            display: none;
            background: none;
            border: none;
            color: var(--text-light);
            font-size: 24px;
            cursor: pointer;
            padding: 5px;
            transition: color 0.3s ease;
        }
        
        .mobile-menu-btn:hover {
            color: var(--primary-color);
        }
        
        /* 网格背景 */
        .grid-bg {
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            z-index: -1;
            opacity: 0.1;
            background-image: 
                linear-gradient(rgba(0, 217, 255, 0.05) 1px, transparent 1px),
                linear-gradient(90deg, rgba(0, 217, 255, 0.05) 1px, transparent 1px);
            background-size: 50px 50px;
        }
        
        /* SEO知识页面特定样式 */
        .seo-page-header {
            background: linear-gradient(135deg, rgba(0, 217, 255, 0.05), rgba(138, 43, 226, 0.05));
            border-radius: 20px;
            padding: 40px 35px;
            margin: 40px 0;
            text-align: center;
            border: 1px solid rgba(0, 217, 255, 0.1);
            position: relative;
            overflow: hidden;
            backdrop-filter: blur(10px);
        }
        
        .seo-page-header h1 {
            color: var(--primary-color);
            font-size: 36px;
            font-family: 'Orbitron', sans-serif;
            margin-bottom: 15px;
            position: relative;
            display: inline-block;
        }
        
        .seo-page-header p {
            color: var(--text-dim);
            font-size: 18px;
            max-width: 800px;
            margin: 0 auto;
            line-height: 1.7;
        }
        
        .seo-categories {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
            gap: 30px;
            margin: 50px 0;
        }
        
        .category-card {
            background: var(--card-bg);
            border-radius: 20px;
            padding: 30px;
            transition: all 0.3s ease;
            position: relative;
            border: 1px solid rgba(0, 217, 255, 0.1);
            backdrop-filter: blur(10px);
            height: 100%;
        }
        
        .category-card:hover {
            transform: translateY(-10px);
            box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
            border-color: rgba(0, 217, 255, 0.3);
        }
        
        .category-icon {
            width: 70px;
            height: 70px;
            border-radius: 15px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 32px;
            margin-bottom: 25px;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            color: white;
        }
        
        .category-card h3 {
            font-size: 24px;
            color: var(--text-light);
            margin-bottom: 15px;
            font-family: 'Orbitron', sans-serif;
        }
        
        .category-card p {
            color: var(--text-dim);
            margin-bottom: 20px;
            line-height: 1.7;
        }
        
        .category-topics {
            margin-top: 20px;
        }
        
        .topic-item {
            display: flex;
            align-items: center;
            padding: 12px 0;
            border-bottom: 1px solid rgba(255, 255, 255, 0.05);
        }
        
        .topic-item:last-child {
            border-bottom: none;
        }
        
        .topic-icon {
            color: var(--primary-color);
            margin-right: 15px;
            font-size: 14px;
        }
        
        .topic-text {
            flex: 1;
            color: var(--text-light);
        }
        
        /* SEO文章列表 */
        .articles-section {
            margin: 60px 0;
        }
        
        .section-title {
            color: var(--primary-color);
            font-size: 32px;
            font-family: 'Orbitron', sans-serif;
            margin-bottom: 30px;
            display: flex;
            align-items: center;
            gap: 15px;
        }
        
        .section-title i {
            font-size: 28px;
        }
        
        .articles-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
            gap: 30px;
        }
        
        .article-card {
            background: var(--card-bg);
            border-radius: 15px;
            overflow: hidden;
            transition: all 0.3s ease;
            border: 1px solid rgba(0, 217, 255, 0.1);
            backdrop-filter: blur(10px);
        }
        
        .article-card:hover {
            transform: translateY(-5px);
            box-shadow: 0 15px 30px rgba(0, 0, 0, 0.3);
            border-color: rgba(0, 217, 255, 0.3);
        }
        
        .article-image {
            height: 200px;
            background: linear-gradient(135deg, rgba(0, 217, 255, 0.2), rgba(138, 43, 226, 0.2));
            display: flex;
            align-items: center;
            justify-content: center;
            color: var(--primary-color);
            font-size: 48px;
        }
        
        .article-content {
            padding: 25px;
        }
        
        .article-meta {
            display: flex;
            justify-content: space-between;
            margin-bottom: 15px;
            font-size: 14px;
        }
        
        .article-date {
            color: var(--text-dim);
        }
        
        .article-category {
            background: rgba(0, 217, 255, 0.1);
            color: var(--primary-color);
            padding: 4px 12px;
            border-radius: 20px;
            font-size: 12px;
        }
        
        .article-content h3 {
            font-size: 20px;
            color: var(--text-light);
            margin-bottom: 15px;
            line-height: 1.4;
        }
        
        .article-content p {
            color: var(--text-dim);
            margin-bottom: 20px;
            line-height: 1.6;
        }
        
        .read-more {
            display: inline-flex;
            align-items: center;
            color: var(--primary-color);
            font-weight: 600;
            text-decoration: none;
            transition: all 0.3s ease;
        }
        
        .read-more:hover {
            color: var(--accent-color);
            gap: 10px;
        }
        
        .read-more i {
            margin-left: 8px;
            transition: all 0.3s ease;
        }
        
        /* SEO工具介绍 */
        .tools-section {
            background: linear-gradient(135deg, rgba(0, 217, 255, 0.05), rgba(138, 43, 226, 0.05));
            border-radius: 20px;
            padding: 40px;
            margin: 60px 0;
            border: 1px solid rgba(0, 217, 255, 0.1);
            backdrop-filter: blur(10px);
        }
        
        .tools-grid {
            display: grid;
            grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
            gap: 25px;
            margin-top: 30px;
        }
        
        .tool-item {
            background: rgba(5, 8, 17, 0.7);
            border-radius: 15px;
            padding: 25px;
            text-align: center;
            transition: all 0.3s ease;
            border: 1px solid rgba(0, 217, 255, 0.1);
        }
        
        .tool-item:hover {
            transform: translateY(-5px);
            border-color: var(--primary-color);
            background: rgba(10, 20, 40, 0.8);
        }
        
        .tool-icon {
            width: 60px;
            height: 60px;
            border-radius: 50%;
            background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
            display: flex;
            align-items: center;
            justify-content: center;
            margin: 0 auto 20px;
            color: white;
            font-size: 24px;
        }
        
        .tool-item h4 {
            color: var(--text-light);
            margin-bottom: 10px;
            font-size: 18px;
        }
        
        .tool-item p {
            color: var(--text-dim);
            font-size: 14px;
            line-height: 1.6;
        }
        
        /* 页脚 */
        footer {
            text-align: center;
            padding: 40px 0;
            border-top: 1px solid rgba(255, 255, 255, 0.05);
            margin-top: 60px;
            color: var(--text-dim);
            font-size: 15px;
            position: relative;
        }
        
        footer::before {
            content: '';
            position: absolute;
            top: 0;
            left: 50%;
            transform: translateX(-50%);
            width: 200px;
            height: 1px;
            background: linear-gradient(90deg, transparent, var(--primary-color), transparent);
        }
        
        .copyright {
            margin-bottom: 15px;
        }
        
        .footer-content {
            text-align: center;
        }

        .seo-info {
            color: var(--text-dim);
            font-size: 14px;
            margin: 15px 0;
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
            line-height: 1.6;
        }

        .footer-links {
            display: flex;
            justify-content: center;
            flex-wrap: wrap;
            gap: 20px;
            margin-top: 25px;
        }

        .footer-links a {
            color: var(--text-dim);
            text-decoration: none;
            transition: all 0.3s ease;
            font-size: 14px;
            padding: 8px 15px;
            border-radius: 20px;
            background: rgba(255, 255, 255, 0.03);
            border: 1px solid rgba(255, 255, 255, 0.05);
        }

        .footer-links a:hover {
            color: var(--primary-color);
            background: rgba(0, 217, 255, 0.1);
            border-color: rgba(0, 217, 255, 0.2);
        }
        
        /* 响应式设计 */
        @media (max-width: 900px) {
            .seo-categories {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .articles-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .tools-grid {
                grid-template-columns: repeat(2, 1fr);
            }
            
            .seo-page-header {
                padding: 30px 25px;
            }
            
            .seo-page-header h1 {
                font-size: 30px;
            }
        }
        
        @media (max-width: 768px) {
            .nav-menu {
                position: fixed;
                top: 70px;
                left: -100%;
                width: 100%;
                height: calc(100vh - 70px);
                background: rgba(5, 8, 17, 0.98);
                flex-direction: column;
                align-items: center;
                justify-content: flex-start;
                padding-top: 40px;
                gap: 0;
                transition: left 0.3s ease;
                backdrop-filter: blur(10px);
                border-top: 1px solid rgba(0, 217, 255, 0.1);
            }
            
            .nav-menu.active {
                left: 0;
            }
            
            .nav-item {
                width: 100%;
                text-align: center;
            }
            
            .nav-link {
                display: block;
                padding: 20px;
                border-bottom: 1px solid rgba(255, 255, 255, 0.05);
                font-size: 18px;
            }
            
            .nav-link:hover {
                background: rgba(0, 217, 255, 0.05);
            }
            
            .mobile-menu-btn {
                display: block;
            }
            
            body {
                padding-top: 70px;
            }
        }
        
        @media (max-width: 600px) {
            .seo-categories {
                grid-template-columns: 1fr;
            }
            
            .articles-grid {
                grid-template-columns: 1fr;
            }
            
            .tools-grid {
                grid-template-columns: 1fr;
            }
            
            .seo-page-header h1 {
                font-size: 26px;
            }
            
            .seo-page-header p {
                font-size: 16px;
            }
            
            .section-title {
                font-size: 26px;
            }
        }