:root {
            --primary-color: #0056b3; /* 科技蓝 */
            --secondary-color: #004494; /* 深蓝 */
            --text-color: #333333; /* 深灰 */
            --text-secondary: #666666; /* 浅灰 */
            --bg-light: #f8f9fa; /* 浅灰背景 */
            --accent-color: #28a745; /* 成功绿 */
            --btn-gradient-start: #007bff;
            --btn-gradient-end: #0056b3;
            --download-btn-color: #ff9800; /* 橙色高亮下载按钮 */
        }

        body {
            font-family: "Segoe UI", "Microsoft YaHei", Arial, sans-serif;
            color: var(--text-color);
            line-height: 1.6;
            background-color: #fff;
        }

        /* 头部导航调整 */
        .ai-header { box-shadow: 0 2px 10px rgba(0,0,0,0.05); position: relative; z-index: 100; }

        /* 首屏 Hero Section */
        .hero {
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            padding: 4rem 0 6rem;
            text-align: center;
            position: relative;
            overflow: hidden;
        }

        /* 装饰背景 */
        .hero::before {
            content: '';
            position: absolute;
            top: -50%;
            left: -50%;
            width: 200%;
            height: 200%;
            background: radial-gradient(circle, rgba(255,255,255,0.8) 0%, rgba(255,255,255,0) 70%);
            pointer-events: none;
        }

        .container {
            max-width: 1200px;
            margin: 0 auto;
            padding: 0 20px;
            position: relative;
            z-index: 10;
        }

        .hero-logo-text {
            font-size: 3.5rem;
            font-weight: 900;
            color: var(--primary-color);
            margin-bottom: 0.5rem;
            letter-spacing: -1px;
            display: inline-block;
            background: linear-gradient(45deg, #0056b3, #00a8ff);
            -webkit-background-clip: text;
            -webkit-text-fill-color: transparent;
        }

        .hero-logo-wrapper {
            margin-bottom: 1rem;
            animation: float 3s ease-in-out infinite;
        }

        .hero-logo-img {
            width: 100px;
            height: auto;
            display: block;
            margin: 0 auto;
            filter: drop-shadow(0 10px 15px rgba(0,0,0,0.1));
        }

        /* 按钮光效 */
        .cta-shine {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: linear-gradient(to right, rgba(255,255,255,0) 0%, rgba(255,255,255,0.4) 50%, rgba(255,255,255,0) 100%);
            transform: skewX(-20deg) translateX(-150%);
            animation: shine 3s infinite;
            pointer-events: none;
        }

        @keyframes shine {
            0% { transform: skewX(-20deg) translateX(-150%); }
            20% { transform: skewX(-20deg) translateX(150%); }
            100% { transform: skewX(-20deg) translateX(150%); }
        }

        @keyframes float {
            0% { transform: translateY(0px); }
            50% { transform: translateY(-10px); }
            100% { transform: translateY(0px); }
        }

        .hero h1 {
            font-size: 3rem;
            font-weight: 800;
            color: #2c3e50;
            margin-bottom: 1rem;
        }

        .subtitle {
            font-size: 1.5rem;
            color: var(--text-secondary);
            margin-bottom: 3rem;
            font-weight: 300;
            max-width: 800px;
            margin-left: auto;
            margin-right: auto;
        }

        /* 主要下载按钮 */
        .cta-primary {
            display: inline-block;
            background: linear-gradient(135deg, #28a745, #218838);
            color: #fff;
            padding: 1.2rem 5rem;
            border-radius: 8px;
            font-size: 1.8rem;
            font-weight: 700;
            box-shadow: 0 10px 25px rgba(40, 167, 69, 0.3);
            transition: all 0.3s ease;
            border: 2px solid rgba(255,255,255,0.2);
            position: relative;
            overflow: hidden;
        }

        .cta-primary:hover {
            transform: translateY(-6px);
            box-shadow: 0 20px 40px rgba(40, 167, 69, 0.5);
            background: linear-gradient(135deg, #34ce57, #28a745);
        }

        .download-tip {
            margin-top: 0;
            font-size: 0.9rem;
            color: #666;
            background: rgba(255,255,255,0.6);
            display: inline-block;
            padding: 5px 15px;
            border-radius: 20px;
        }

        /* 核心特性图标 */
        .hero-features {
            display: flex;
            justify-content: center;
            gap: 3rem;
            margin-top: 4rem;
            flex-wrap: wrap;
        }

        .hero-feature-item {
            text-align: center;
            color: var(--text-color);
            transition: transform 0.3s;
        }

        .hero-feature-item:hover {
            transform: translateY(-5px);
        }

        .hero-feature-icon {
            width: 60px;
            height: 60px;
            background: #fff;
            border-radius: 15px;
            display: flex;
            align-items: center;
            justify-content: center;
            font-size: 1.8rem;
            box-shadow: 0 5px 15px rgba(0,0,0,0.05);
            margin: 0 auto 10px;
            color: var(--primary-color);
        }

        .hero-feature-text {
            font-weight: 600;
            font-size: 1rem;
        }

        /* 详细功能区 */
        .features-section {
            padding: 5rem 0;
            background: #fff;
        }

        .section-title {
            text-align: center;
            font-size: 2.2rem;
            font-weight: 700;
            margin-bottom: 4rem;
            color: #2c3e50;
        }

        .features-grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
            gap: 2rem;
        }

        .feature-card {
            padding: 2rem;
            border-radius: 12px;
            background: #f8f9fa;
            border: 1px solid #eee;
            transition: all 0.3s ease;
        }

        .feature-card:hover {
            box-shadow: 0 10px 30px rgba(0,0,0,0.08);
            transform: translateY(-5px);
            border-color: var(--primary-color);
        }

        .feature-card-icon {
            font-size: 2.5rem;
            margin-bottom: 1.5rem;
            color: var(--primary-color);
        }

        .feature-card h3 {
            font-size: 1.4rem;
            margin-bottom: 1rem;
            color: #2c3e50;
        }

        .feature-card p {
            color: #666;
            font-size: 1rem;
        }

        /* 优势对比/下载条 */
        .download-bar {
            background: #e9ecef;
            padding: 4rem 0;
            text-align: center;
        }

        .secondary-btn {
            display: inline-block;
            background: #fff;
            color: var(--primary-color);
            border: 2px solid var(--primary-color);
            padding: 0.8rem 3rem;
            border-radius: 50px;
            font-size: 1.2rem;
            font-weight: 600;
            margin: 0 1rem;
            transition: all 0.3s;
        }

        .secondary-btn:hover {
            background: var(--primary-color);
            color: #fff;
        }

        .primary-btn-small {
            display: inline-block;
            background: var(--primary-color);
            color: #fff;
            padding: 0.8rem 3rem;
            border-radius: 50px;
            font-size: 1.2rem;
            font-weight: 600;
            margin: 0 1rem;
            box-shadow: 0 5px 15px rgba(0,86,179,0.3);
            transition: all 0.3s;
        }

        .primary-btn-small:hover {
            background: var(--secondary-color);
            transform: translateY(-2px);
        }

        /* FAQ Section */
        .faq-section {
            padding: 5rem 0;
            background: #fff;
        }

        .faq-item {
            border-bottom: 1px solid #eee;
            padding: 1.5rem 0;
            cursor: pointer;
        }

        .faq-question {
            font-size: 1.2rem;
            font-weight: 600;
            color: #2c3e50;
            display: flex;
            justify-content: space-between;
            align-items: center;
        }

        .faq-question::after {
            content: '+';
            font-size: 1.5rem;
            color: var(--primary-color);
        }

        .faq-answer {
            max-height: 0;
            overflow: hidden;
            transition: max-height 0.3s ease;
            color: #666;
            margin-top: 0;
        }

        .faq-item.active .faq-answer {
            max-height: 200px;
            margin-top: 1rem;
        }

        .faq-item.active .faq-question::after {
            content: '-';
        }

        /* 底部悬浮栏 */
        .bottom-bar {
            position: fixed;
            bottom: 0;
            left: 0;
            width: 100%;
            background: rgba(255,255,255,0.95);
            backdrop-filter: blur(10px);
            padding: 15px 0;
            box-shadow: 0 -5px 20px rgba(0,0,0,0.1);
            z-index: 999;
            transform: translateY(100%);
            transition: transform 0.3s;
            border-top: 1px solid #eee;
        }

        .bottom-bar.show {
            transform: translateY(0);
        }

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

        .bottom-logo {
            font-weight: 800;
            font-size: 1.5rem;
            color: var(--primary-color);
            display: flex;
            align-items: center;
            gap: 10px;
        }

        .bottom-cta {
            background: linear-gradient(135deg, #28a745, #218838);
            color: #fff;
            padding: 0.6rem 2rem;
            border-radius: 30px;
            font-weight: 700;
            box-shadow: 0 5px 15px rgba(40, 167, 69, 0.3);
        }

        .close-bar {
            position: absolute;
            right: 10px;
            top: 50%;
            transform: translateY(-50%);
            cursor: pointer;
            color: #999;
            font-size: 1.5rem;
            display: none; /* PC端通常不需要关闭，或者放右侧 */
        }

        @media (max-width: 768px) {
            .hero h1 { font-size: 2rem; }
            .hero-features { gap: 1rem; }
            .cta-primary { padding: 1rem 3rem; font-size: 1.4rem; width: 80%; box-sizing: border-box; }
            .bottom-bar-content { flex-direction: column; gap: 10px; }
        }