* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        html, body {
            height: 100%;
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
            color: #333;
            line-height: 1.6;
            background-color: #f8f9fa;
        }

        /* 导航栏 */
        .gcs5s-navbar {
            background: linear-gradient(135deg, #ffffff 0%, #f5f5f5 100%);
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
            position: sticky;
            top: 0;
            z-index: 100;
        }

        .gcs5s-navbar-container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
            display: flex;
            justify-content: space-between;
            align-items: center;
            height: 70px;
        }

        .gcs5s-logo {
            display: flex;
            align-items: center;
            gap: 10px;
            text-decoration: none;
            color: #333;
            font-weight: 600;
            font-size: 18px;
        }

        .gcs5s-logo img {
            height: 40px;
            width: auto;
        }

        .gcs5s-nav-menu {
            display: flex;
            gap: 30px;
            list-style: none;
        }

        .gcs5s-nav-link {
            text-decoration: none;
            color: #666;
            font-size: 15px;
            font-weight: 500;
            transition: color 0.3s ease;
            border-bottom: 2px solid transparent;
            padding-bottom: 5px;
        }

        .gcs5s-nav-link:hover {
            color: #0066cc;
            border-bottom-color: #0066cc;
        }

        /* 主横幅 */
        .gcs5s-hero {
            background: linear-gradient(135deg, #0066cc 0%, #0052a3 100%);
            color: white;
            padding: 80px 20px;
            text-align: center;
        }

        .gcs5s-hero-container {
            max-width: 1000px;
            margin: 0 auto;
        }

        .gcs5s-hero-title {
            font-size: 48px;
            font-weight: 700;
            margin-bottom: 20px;
            letter-spacing: -0.5px;
        }

        .gcs5s-hero-subtitle {
            font-size: 20px;
            margin-bottom: 40px;
            opacity: 0.95;
            font-weight: 300;
        }

        /* 下载按钮区域 */
        .gcs5s-download-section {
            background: white;
            padding: 60px 20px;
            margin-top: -40px;
            position: relative;
            z-index: 10;
        }

        .gcs5s-download-container {
            max-width: 1000px;
            margin: 0 auto;
        }

        .gcs5s-download-box {
            background: linear-gradient(135deg, #ffffff 0%, #f9f9f9 100%);
            border: 2px solid #e0e0e0;
            border-radius: 12px;
            padding: 50px 40px;
            text-align: center;
            box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
        }

        .gcs5s-version-info {
            display: flex;
            justify-content: center;
            gap: 40px;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }

        .gcs5s-info-item {
            text-align: center;
        }

        .gcs5s-info-label {
            font-size: 13px;
            color: #999;
            text-transform: uppercase;
            letter-spacing: 1px;
            margin-bottom: 8px;
        }

        .gcs5s-info-value {
            font-size: 18px;
            font-weight: 600;
            color: #0066cc;
        }

        .gcs5s-btn-group {
            display: flex;
            gap: 20px;
            justify-content: center;
            margin-bottom: 30px;
            flex-wrap: wrap;
        }

        .gcs5s-btn-primary {
            background: linear-gradient(135deg, #0066cc 0%, #0052a3 100%);
            color: white;
            border: none;
            padding: 16px 50px;
            font-size: 16px;
            font-weight: 600;
            border-radius: 8px;
            cursor: pointer;
            transition: all 0.3s ease;
            box-shadow: 0 4px 15px rgba(0, 102, 204, 0.3);
            min-width: 200px;
        }

        .gcs5s-btn-primary:hover {
            transform: translateY(-2px);
            box-shadow: 0 6px 25px rgba(0, 102, 204, 0.4);
        }

        .gcs5s-btn-secondary {
            background: white;
            color: #0066cc;
            border: 2px solid #0066cc;
            padding: 14px 40px;
            font-size: 15px;
            font-weight: 600;
            border-radius: 8px;
            cursor: pointer;
            transition: all 0.3s ease;
            min-width: 180px;
        }

        .gcs5s-btn-secondary:hover {
            background: #f0f7ff;
            transform: translateY(-2px);
        }

        .gcs5s-system-requirement {
            background: #f5f5f5;
            padding: 20px 30px;
            border-radius: 8px;
            text-align: left;
            margin-top: 20px;
        }

        .gcs5s-requirement-title {
            font-size: 14px;
            font-weight: 600;
            color: #333;
            margin-bottom: 12px;
        }

        .gcs5s-requirement-text {
            font-size: 13px;
            color: #666;
            line-height: 1.8;
        }

        /* 特性展示区 */
        .gcs5s-features {
            padding: 80px 20px;
            background: white;
        }

        .gcs5s-features-container {
            max-width: 1000px;
            margin: 0 auto;
        }

        .gcs5s-section-title {
            font-size: 32px;
            font-weight: 700;
            text-align: center;
            margin-bottom: 50px;
            color: #333;
        }

        .gcs5s-features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 30px;
        }

        .gcs5s-feature-card {
            background: #f9f9f9;
            padding: 30px;
            border-radius: 8px;
            border-left: 4px solid #0066cc;
            transition: all 0.3s ease;
        }

        .gcs5s-feature-card:hover {
            box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
            transform: translateY(-4px);
        }

        .gcs5s-feature-icon {
            font-size: 32px;
            margin-bottom: 15px;
        }

        .gcs5s-feature-title {
            font-size: 18px;
            font-weight: 600;
            margin-bottom: 10px;
            color: #333;
        }

        .gcs5s-feature-desc {
            font-size: 14px;
            color: #666;
            line-height: 1.6;
        }

        /* 安全认证区 */
        .gcs5s-security {
            background: #f5f5f5;
            padding: 60px 20px;
        }

        .gcs5s-security-container {
            max-width: 1000px;
            margin: 0 auto;
            text-align: center;
        }

        .gcs5s-security-title {
            font-size: 24px;
            font-weight: 700;
            margin-bottom: 30px;
            color: #333;
        }

        .gcs5s-security-badges {
            display: flex;
            justify-content: center;
            gap: 40px;
            flex-wrap: wrap;
            margin-bottom: 30px;
        }

        .gcs5s-badge {
            text-align: center;
        }

        .gcs5s-badge-icon {
            font-size: 40px;
            margin-bottom: 10px;
        }

        .gcs5s-badge-text {
            font-size: 13px;
            color: #666;
            font-weight: 500;
        }

        /* 常见问题 */
        .gcs5s-faq {
            padding: 80px 20px;
            background: white;
        }

        .gcs5s-faq-container {
            max-width: 800px;
            margin: 0 auto;
        }

        .gcs5s-faq-item {
            margin-bottom: 20px;
            border-bottom: 1px solid #e0e0e0;
            padding-bottom: 20px;
        }

        .gcs5s-faq-item:last-child {
            border-bottom: none;
        }

        .gcs5s-faq-question {
            font-size: 16px;
            font-weight: 600;
            color: #333;
            margin-bottom: 10px;
            cursor: pointer;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .gcs5s-faq-answer {
            font-size: 14px;
            color: #666;
            line-height: 1.8;
        }

        /* 页脚 */
        .gcs5s-footer {
            background: #333;
            color: white;
            padding: 40px 20px 20px;
            margin-top: 60px;
        }

        .gcs5s-footer-container {
            max-width: 1200px;
            margin: 0 auto;
        }

        .gcs5s-footer-content {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 30px;
            margin-bottom: 30px;
        }

        .gcs5s-footer-section h3 {
            font-size: 15px;
            margin-bottom: 15px;
            color: #fff;
        }

        .gcs5s-footer-section ul {
            list-style: none;
        }

        .gcs5s-footer-section li {
            margin-bottom: 8px;
        }

        .gcs5s-footer-section a {
            color: #bbb;
            text-decoration: none;
            font-size: 13px;
            transition: color 0.3s ease;
        }

        .gcs5s-footer-section a:hover {
            color: #0066cc;
        }

        .gcs5s-footer-bottom {
            border-top: 1px solid #555;
            padding-top: 20px;
            text-align: center;
            font-size: 12px;
            color: #999;
        }

        /* 响应式设计 */
        @media (max-width: 768px) {
            .gcs5s-hero-title {
                font-size: 32px;
            }

            .gcs5s-hero-subtitle {
                font-size: 16px;
            }

            .gcs5s-nav-menu {
                gap: 15px;
            }

            .gcs5s-nav-link {
                font-size: 13px;
            }

            .gcs5s-btn-primary, .gcs5s-btn-secondary {
                min-width: 160px;
                padding: 12px 30px;
                font-size: 14px;
            }

            .gcs5s-btn-group {
                flex-direction: column;
            }

            .gcs5s-download-box {
                padding: 30px 20px;
            }

            .gcs5s-version-info {
                gap: 20px;
            }

            .gcs5s-section-title {
                font-size: 24px;
            }

            .gcs5s-security-badges {
                gap: 20px;
            }
        }

        @media (max-width: 480px) {
            .gcs5s-navbar-container {
                height: 60px;
            }

            .gcs5s-nav-menu {
                gap: 10px;
            }

            .gcs5s-nav-link {
                font-size: 12px;
            }

            .gcs5s-hero {
                padding: 50px 15px;
            }

            .gcs5s-hero-title {
                font-size: 24px;
                margin-bottom: 15px;
            }

            .gcs5s-download-section {
                padding: 40px 15px;
            }

            .gcs5s-version-info {
                flex-direction: column;
                gap: 15px;
            }

            .gcs5s-features, .gcs5s-faq {
                padding: 50px 15px;
            }
        }