/* ==================== 全局样式 ==================== */
        * {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }

        :root {
            --primary-color: #1f4788;
            --secondary-color: #2e5fa3;
            --accent-color: #00a8e8;
            --light-bg: #f5f7fa;
            --text-dark: #333333;
            --text-light: #666666;
            --border-color: #e0e0e0;
            --success-color: #27ae60;
        }

        html {
            scroll-behavior: smooth;
        }

        body {
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen', 'Ubuntu', 'Cantarell', sans-serif;
            color: var(--text-dark);
            line-height: 1.6;
            background-color: #ffffff;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
        }

        /* ==================== Header 导航 ==================== */
        header {
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            color: white;
            padding: 0;
            position: sticky;
            top: 0;
            z-index: 100;
            box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
        }

        .header-content {
            display: flex;
            justify-content: space-between;
            align-items: center;
            padding: 15px 20px;
            max-width: 1200px;
            margin: 0 auto;
        }

        .logo {
            font-size: 24px;
            font-weight: bold;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .logo-icon {
            width: 40px;
            height: 40px;
            background: rgba(255, 255, 255, 0.2);
            border-radius: 8px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 24px;
        }

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

        .nav-menu a {
            color: white;
            text-decoration: none;
            font-size: 14px;
            transition: opacity 0.3s;
            position: relative;
        }

        .nav-menu a:hover {
            opacity: 0.8;
        }

        .nav-menu a::after {
            content: '';
            position: absolute;
            bottom: -5px;
            left: 0;
            width: 0;
            height: 2px;
            background: var(--accent-color);
            transition: width 0.3s;
        }

        .nav-menu a:hover::after {
            width: 100%;
        }

        /* ==================== 语言选择下拉框 ==================== */
        .lang-selector {
            position: relative;
            display: inline-block;
        }

        .lang-selector-btn {
            background: rgba(255, 255, 255, 0.2);
            border: 1px solid rgba(255, 255, 255, 0.3);
            color: white;
            padding: 8px 15px;
            border-radius: 4px;
            cursor: pointer;
            font-size: 14px;
            transition: all 0.3s;
            display: flex;
            align-items: center;
            gap: 8px;
            min-width: 120px;
            justify-content: space-between;
        }

        .lang-selector-btn:hover {
            background: rgba(255, 255, 255, 0.3);
            border-color: rgba(255, 255, 255, 0.5);
        }

        .lang-selector-btn.active {
            background: var(--accent-color);
            border-color: var(--accent-color);
        }

        .lang-selector-btn::after {
            content: '▼';
            font-size: 10px;
            transition: transform 0.3s;
        }

        .lang-selector-btn.open::after {
            transform: rotate(180deg);
        }

        .lang-dropdown {
            position: absolute;
            top: 100%;
            right: 0;
            background: white;
            border: 1px solid var(--border-color);
            border-radius: 4px;
            min-width: 150px;
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.15);
            opacity: 0;
            visibility: hidden;
            transform: translateY(-10px);
            transition: all 0.3s ease;
            z-index: 1000;
            margin-top: 5px;
            overflow: hidden;
        }

        .lang-dropdown.show {
            opacity: 1;
            visibility: visible;
            transform: translateY(0);
        }

        .lang-option {
            padding: 12px 16px;
            cursor: pointer;
            color: var(--text-dark);
            transition: all 0.2s;
            display: flex;
            align-items: center;
            gap: 10px;
            border-bottom: 1px solid var(--border-color);
        }

        .lang-option:last-child {
            border-bottom: none;
        }

        .lang-option:hover {
            background: var(--light-bg);
            color: var(--accent-color);
        }

        .lang-option.active {
            background: var(--light-bg);
            color: var(--accent-color);
            font-weight: 600;
        }

        .lang-option::before {
            content: '';
            width: 4px;
            height: 4px;
            border-radius: 50%;
            background: transparent;
            transition: all 0.2s;
        }

        .lang-option.active::before {
            background: var(--accent-color);
            width: 6px;
            height: 6px;
        }

        .lang-flag {
            font-size: 16px;
        }

        .menu-toggle {
            display: none;
            background: none;
            border: none;
            color: white;
            font-size: 24px;
            cursor: pointer;
        }

        /* ==================== 侧边栏菜单（移动端） ==================== */
        .sidebar-menu {
            position: fixed;
            right: -300px;
            top: 0;
            width: 300px;
            height: 100vh;
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            z-index: 99;
            transition: right 0.3s ease;
            overflow-y: auto;
            padding-top: 60px;
        }

        .sidebar-menu.active {
            right: 0;
        }

        .sidebar-menu a {
            display: block;
            color: white;
            text-decoration: none;
            padding: 15px 20px;
            border-bottom: 1px solid rgba(255, 255, 255, 0.1);
            transition: background 0.3s;
        }

        .sidebar-menu a:hover {
            background: rgba(255, 255, 255, 0.1);
        }

        .sidebar-close {
            position: absolute;
            top: 15px;
            right: 15px;
            background: none;
            border: none;
            color: white;
            font-size: 28px;
            cursor: pointer;
        }

        /* ==================== Hero Banner ==================== */
        .hero {
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            color: white;
            padding: 80px 20px;
            text-align: center;
            position: relative;
            overflow: hidden;
        }

        .hero::before {
            content: '';
            position: absolute;
            top: -50%;
            right: -10%;
            width: 500px;
            height: 500px;
            background: radial-gradient(circle, rgba(255, 255, 255, 0.1) 0%, transparent 70%);
            border-radius: 50%;
        }

        .hero-content {
            position: relative;
            z-index: 2;
            max-width: 800px;
            margin: 0 auto;
        }

        .hero h1 {
            font-size: 48px;
            margin-bottom: 20px;
            font-weight: 700;
            line-height: 1.2;
        }

        .hero p {
            font-size: 18px;
            margin-bottom: 30px;
            opacity: 0.95;
        }

        .hero-buttons {
            display: flex;
            gap: 20px;
            justify-content: center;
            flex-wrap: wrap;
        }

        .btn {
            padding: 14px 40px;
            border: none;
            border-radius: 6px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
            text-decoration: none;
            display: inline-block;
        }

        .btn-primary {
            background: var(--accent-color);
            color: white;
        }

        .btn-primary:hover {
            background: #0096cc;
            transform: translateY(-2px);
            box-shadow: 0 8px 20px rgba(0, 168, 232, 0.3);
        }

        .btn-secondary {
            background: white;
            color: var(--primary-color);
            border: 2px solid white;
        }

        .btn-secondary:hover {
            background: transparent;
            color: white;
            transform: translateY(-2px);
        }

        /* ==================== 功能特性模块 ==================== */
        .features {
            padding: 80px 20px;
            background: var(--light-bg);
        }

        .section-title {
            text-align: center;
            font-size: 36px;
            margin-bottom: 50px;
            color: var(--primary-color);
            position: relative;
        }

        .section-title::after {
            content: '';
            display: block;
            width: 60px;
            height: 4px;
            background: var(--accent-color);
            margin: 15px auto 0;
            border-radius: 2px;
        }

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

        .feature-card {
            background: white;
            padding: 40px 25px;
            border-radius: 10px;
            text-align: center;
            transition: all 0.3s;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
            border-top: 4px solid var(--accent-color);
        }

        .feature-card:hover {
            transform: translateY(-8px);
            box-shadow: 0 12px 30px rgba(0, 0, 0, 0.15);
        }

        .feature-icon {
            font-size: 48px;
            margin-bottom: 15px;
            height: 60px;
            display: flex;
            align-items: center;
            justify-content: center;
        }

        .feature-card h3 {
            font-size: 20px;
            margin-bottom: 15px;
            color: var(--primary-color);
        }

        .feature-card p {
            color: var(--text-light);
            font-size: 14px;
            line-height: 1.8;
        }

        /* ==================== 下载模块 ==================== */
        .download-section {
            padding: 80px 20px;
            background: white;
        }

        .download-container {
            max-width: 900px;
            margin: 0 auto;
        }

        .download-cards {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 30px;
            margin-top: 40px;
        }

        .download-card {
            background: linear-gradient(135deg, var(--light-bg) 0%, #ffffff 100%);
            padding: 40px 30px;
            border-radius: 10px;
            border: 2px solid var(--border-color);
            text-align: center;
            transition: all 0.3s;
        }

        .download-card:hover {
            border-color: var(--accent-color);
            box-shadow: 0 10px 30px rgba(0, 168, 232, 0.15);
        }

        .download-card h3 {
            font-size: 24px;
            margin-bottom: 15px;
            color: var(--primary-color);
        }

        .download-card p {
            color: var(--text-light);
            margin-bottom: 20px;
            font-size: 14px;
        }

        .download-btn {
            background: var(--accent-color);
            color: white;
            padding: 12px 30px;
            border: none;
            border-radius: 6px;
            cursor: pointer;
            font-size: 16px;
            font-weight: 600;
            transition: all 0.3s;
            width: 100%;
            text-decoration: none;
            display: inline-block;
        }

        .download-btn:hover {
            background: #0096cc;
            transform: translateY(-2px);
        }

        .download-info {
            font-size: 12px;
            color: var(--text-light);
            margin-top: 15px;
        }

        /* ==================== 应用场景模块 ==================== */
        .scenarios {
            padding: 80px 20px;
            background: var(--light-bg);
        }

        .scenarios-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 25px;
            margin-top: 40px;
        }

        .scenario-item {
            background: white;
            padding: 30px 25px;
            border-radius: 8px;
            border-left: 4px solid var(--accent-color);
            transition: all 0.3s;
        }

        .scenario-item:hover {
            box-shadow: 0 8px 20px rgba(0, 0, 0, 0.1);
            transform: translateX(5px);
        }

        .scenario-item h4 {
            color: var(--primary-color);
            margin-bottom: 10px;
            font-size: 18px;
        }

        .scenario-item p {
            color: var(--text-light);
            font-size: 14px;
            line-height: 1.8;
        }

        /* ==================== 系统要求模块 ==================== */
        .requirements {
            padding: 80px 20px;
            background: white;
        }

        .requirements-content {
            max-width: 900px;
            margin: 0 auto;
        }

        .requirement-item {
            display: flex;
            gap: 20px;
            margin-bottom: 30px;
            padding: 20px;
            background: var(--light-bg);
            border-radius: 8px;
            border-left: 4px solid var(--accent-color);
        }

        .requirement-icon {
            font-size: 32px;
            flex-shrink: 0;
        }

        .requirement-text h4 {
            color: var(--primary-color);
            margin-bottom: 8px;
            font-size: 16px;
        }

        .requirement-text p {
            color: var(--text-light);
            font-size: 14px;
            line-height: 1.6;
        }

        /* ==================== FAQ 模块 ==================== */
        .faq {
            padding: 80px 20px;
            background: var(--light-bg);
        }

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

        .faq-item {
            background: white;
            margin-bottom: 15px;
            border-radius: 8px;
            overflow: hidden;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
        }

        .faq-question {
            padding: 20px;
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            color: white;
            cursor: pointer;
            display: flex;
            justify-content: space-between;
            align-items: center;
            font-weight: 600;
            transition: all 0.3s;
        }

        .faq-question:hover {
            background: linear-gradient(135deg, var(--secondary-color) 0%, var(--primary-color) 100%);
        }

        .faq-toggle {
            font-size: 20px;
            transition: transform 0.3s;
        }

        .faq-toggle.active {
            transform: rotate(180deg);
        }

        .faq-answer {
            padding: 0;
            max-height: 0;
            overflow: hidden;
            transition: all 0.3s ease;
            background: white;
        }

        .faq-answer.active {
            padding: 20px;
            max-height: 500px;
        }

        .faq-answer p {
            color: var(--text-light);
            font-size: 14px;
            line-height: 1.8;
        }

        /* ==================== 教程模块 ==================== */
        .tutorials {
            padding: 80px 20px;
            background: white;
        }

        .tutorials-container {
            max-width: 900px;
            margin: 0 auto;
        }

        .tutorial-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 30px;
            margin-top: 40px;
        }

        .tutorial-card {
            background: var(--light-bg);
            border-radius: 10px;
            overflow: hidden;
            transition: all 0.3s;
            box-shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
        }

        .tutorial-card:hover {
            transform: translateY(-8px);
            box-shadow: 0 12px 30px rgba(0, 0, 0, 0.15);
        }

        .tutorial-header {
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            color: white;
            padding: 30px 20px;
            text-align: center;
            font-size: 24px;
        }

        .tutorial-content {
            padding: 25px 20px;
        }

        .tutorial-content h4 {
            color: var(--primary-color);
            margin-bottom: 10px;
            font-size: 16px;
        }

        .tutorial-content p {
            color: var(--text-light);
            font-size: 14px;
            line-height: 1.8;
            margin-bottom: 15px;
        }

        .tutorial-link {
            color: var(--accent-color);
            text-decoration: none;
            font-weight: 600;
            transition: color 0.3s;
        }

        .tutorial-link:hover {
            color: var(--primary-color);
        }

        /* ==================== 友情链接模块 ==================== */
        .links {
            padding: 80px 20px;
            background: var(--light-bg);
        }

        .links-container {
            max-width: 900px;
            margin: 0 auto;
        }

        .links-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
            gap: 20px;
            margin-top: 40px;
        }

        .link-item {
            background: white;
            padding: 20px;
            border-radius: 8px;
            text-align: center;
            border: 2px solid var(--border-color);
            transition: all 0.3s;
        }

        .link-item:hover {
            border-color: var(--accent-color);
            box-shadow: 0 8px 20px rgba(0, 168, 232, 0.15);
        }

        .link-item a {
            color: var(--primary-color);
            text-decoration: none;
            font-weight: 600;
            transition: color 0.3s;
        }

        .link-item a:hover {
            color: var(--accent-color);
        }

        /* ==================== Footer 页脚 ==================== */
        footer {
            background: linear-gradient(135deg, var(--primary-color) 0%, var(--secondary-color) 100%);
            color: white;
            padding: 60px 20px 30px;
        }

        .footer-content {
            max-width: 1200px;
            margin: 0 auto;
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
            gap: 40px;
            margin-bottom: 40px;
        }

        .footer-section h4 {
            margin-bottom: 15px;
            font-size: 16px;
        }

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

        .footer-section ul li {
            margin-bottom: 10px;
        }

        .footer-section a {
            color: rgba(255, 255, 255, 0.8);
            text-decoration: none;
            transition: color 0.3s;
            font-size: 14px;
        }

        .footer-section a:hover {
            color: white;
        }

        .footer-bottom {
            border-top: 1px solid rgba(255, 255, 255, 0.2);
            padding-top: 30px;
            text-align: center;
            font-size: 14px;
            color: rgba(255, 255, 255, 0.8);
        }

        /* ==================== 悬浮模块 ==================== */
        .floating-download {
            position: fixed;
            bottom: 30px;
            left: 30px;
            background: var(--accent-color);
            color: white;
            padding: 15px 25px;
            border-radius: 50px;
            box-shadow: 0 8px 25px rgba(0, 168, 232, 0.3);
            z-index: 90;
            transition: all 0.3s;
            cursor: pointer;
            font-weight: 600;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .floating-download:hover {
            background: #0096cc;
            transform: translateY(-3px);
            box-shadow: 0 12px 35px rgba(0, 168, 232, 0.4);
        }

        .floating-download a {
            color: white;
            text-decoration: none;
            display: flex;
            align-items: center;
            gap: 10px;
        }

        /* ==================== 返回顶部按钮 ==================== */
        .back-to-top {
            position: fixed;
            bottom: 30px;
            right: 30px;
            width: 50px;
            height: 50px;
            background: var(--primary-color);
            color: white;
            border: none;
            border-radius: 50%;
            cursor: pointer;
            display: none;
            align-items: center;
            justify-content: center;
            font-size: 24px;
            z-index: 90;
            transition: all 0.3s;
            box-shadow: 0 8px 25px rgba(31, 71, 136, 0.3);
        }

        .back-to-top:hover {
            background: var(--secondary-color);
            transform: translateY(-3px);
        }

        .back-to-top.show {
            display: flex;
        }

        /* ==================== 响应式设计 ==================== */
        @media (max-width: 768px) {
            .nav-menu {
                display: none;
            }

            .menu-toggle {
                display: block;
            }

            .hero h1 {
                font-size: 32px;
            }

            .hero p {
                font-size: 16px;
            }

            .hero-buttons {
                flex-direction: column;
            }

            .btn {
                width: 100%;
            }

            .section-title {
                font-size: 28px;
            }

            .features-grid,
            .download-cards,
            .scenarios-grid,
            .tutorial-grid,
            .links-grid {
                grid-template-columns: 1fr;
            }

            .floating-download {
                bottom: 20px;
                left: 20px;
                padding: 12px 20px;
                font-size: 14px;
            }

            .back-to-top {
                bottom: 20px;
                right: 20px;
                width: 45px;
                height: 45px;
                font-size: 20px;
            }

            .footer-content {
                grid-template-columns: 1fr;
                gap: 30px;
            }

            .lang-selector-btn {
                min-width: 100px;
                padding: 6px 12px;
                font-size: 12px;
            }

            .lang-dropdown {
                min-width: 140px;
            }

            .lang-option {
                padding: 10px 12px;
                font-size: 13px;
            }
        }

        @media (max-width: 480px) {
            .header-content {
                padding: 12px 15px;
            }

            .logo {
                font-size: 18px;
            }

            .logo-icon {
                width: 35px;
                height: 35px;
            }

            .hero {
                padding: 50px 15px;
            }

            .hero h1 {
                font-size: 24px;
            }

            .hero p {
                font-size: 14px;
            }

            .section-title {
                font-size: 22px;
                margin-bottom: 30px;
            }

            .features-grid,
            .download-cards,
            .scenarios-grid {
                gap: 15px;
            }

            .feature-card,
            .download-card,
            .scenario-item {
                padding: 20px 15px;
            }

            .floating-download {
                bottom: 15px;
                left: 15px;
                padding: 10px 15px;
                font-size: 12px;
            }

            .back-to-top {
                bottom: 15px;
                right: 15px;
                width: 40px;
                height: 40px;
            }

            .lang-selector-btn {
                min-width: 90px;
                padding: 5px 10px;
                font-size: 11px;
            }
        }

        /* ==================== 打印样式 ==================== */
        @media print {
            .floating-download,
            .back-to-top,
            header,
            footer {
                display: none;
            }
        }

        /* ==================== 动画 ==================== */
        @keyframes fadeInUp {
            from {
                opacity: 0;
                transform: translateY(30px);
            }
            to {
                opacity: 1;
                transform: translateY(0);
            }
        }

        .fade-in {
            animation: fadeInUp 0.6s ease-out;
        }