:root {
            --primary-color: #00B5B5; 
            --primary-dark: #008E8E;
            --accent-color: #E8A81C; 
            --text-main: #222;
            --text-muted: #555;
            --bg-light: #F4F8F8;
            --white: #FFFFFF;
        }

        * { margin: 0; padding: 0; box-sizing: border-box; font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif; }
        body { color: var(--text-main); background-color: var(--white); line-height: 1.8; font-size: 18px; }
        .container { max-width: 1200px; margin: 0 auto; padding: 0 25px; }

        /* 导航 */
        header { background: #fff; box-shadow: 0 4px 12px rgba(0,0,0,0.08); position: sticky; top: 0; z-index: 100; }
        .nav-inner { display: flex; justify-content: space-between; align-items: center; height: 90px; }
        .logo { display: flex; align-items: center; font-size: 34px; font-weight: 800; color: var(--primary-color); }
        .logo-box { width: 50px; height: 50px; background: var(--primary-color); border-radius: 12px; margin-right: 12px; display: flex; align-items: center; justify-content: center; color: white; font-size: 32px; font-weight: bold; }

        /* Hero区 */
        .hero { background: linear-gradient(135deg, #00C8C8 0%, var(--primary-color) 100%); padding: 120px 0; color: #fff; text-align: center; }
        .hero-title { font-size: 68px; font-weight: 800; margin-bottom: 25px; padding: 0 10px; }
        .hero-subtitle { font-size: 28px; margin-bottom: 60px; opacity: 0.95; padding: 0 15px; }
        
        /* 下载按钮组 */
        .download-group { display: flex; gap: 30px; justify-content: center; padding: 0 20px; }
        .btn-dl { padding: 22px 55px; border-radius: 60px; font-size: 26px; font-weight: bold; transition: 0.3s; cursor: pointer; text-decoration: none; border: none; display: inline-block; text-align: center; }
        .btn-android { background: var(--accent-color); color: #fff; box-shadow: 0 10px 20px rgba(232, 168, 28, 0.3); }
        .btn-ios { background: #fff; color: var(--primary-color); box-shadow: 0 10px 20px rgba(0,0,0,0.1); }
        .btn-dl:hover { transform: translateY(-5px); box-shadow: 0 15px 30px rgba(0,0,0,0.2); }

       /* 数据与步骤区 */
        .info-section { padding: 100px 0; background: var(--bg-light); }
        .info-inner { display: flex; gap: 50px; align-items: stretch; }
        .data-panel { flex: 1; background: linear-gradient(135deg, var(--primary-color) 0%, var(--primary-dark) 100%); border-radius: 35px; padding: 60px; color: #fff; box-shadow: 0 20px 40px rgba(0, 181, 181, 0.2); }
        .data-value { font-size: 50px; font-weight: 800; color: var(--accent-color); margin-bottom: 5px; }
        .data-label { font-size: 22px; opacity: 0.9; margin-bottom: 35px; }
        .steps-container { flex: 1.5; display: flex; align-items: center; justify-content: space-between; }
        .step-card { text-align: center; flex: 1; padding: 0 10px; }
        .step-num { width: 90px; height: 90px; border: 4px solid var(--primary-color); border-radius: 50%; display: flex; align-items: center; justify-content: center; margin: 0 auto 20px; font-size: 36px; font-weight: 800; color: var(--primary-color); background: #fff; }
        .step-card h4 { font-size: 26px; margin-bottom: 10px; }
        .step-card p { font-size: 19px; color: #666; }

        /* 为什么选择区域 (横版, 500px图) */
        .features-section { padding: 120px 0; }
        .section-title { text-align: center; font-size: 48px; margin-bottom: 80px; font-weight: 800; color: #333; }
        .features-grid-horizontal { display: grid; grid-template-columns: 1fr 1fr; gap: 50px; }
        
        .feature-item-h { 
            background: #fff; 
            border-radius: 25px; 
            overflow: hidden; 
            transition: 0.4s; 
            border: 1px solid #f0f0f0; 
            display: flex; 
            flex-direction: column; 
            align-items: center;
        }
        .feature-item-h:hover { transform: translateY(-10px); box-shadow: 0 20px 40px rgba(0,0,0,0.1); border-color: var(--primary-color); }

        .feature-img {
            width: 500px;
            height: 300px;
            object-fit: cover;
            border-bottom: 5px solid var(--primary-color);
        }

        .feature-content { padding: 40px; width: 100%; max-width: 500px; }
        .feature-content h3 { font-size: 32px; margin-bottom: 15px; color: var(--primary-color); font-weight: 800; }
        .feature-content p { font-size: 20px; color: var(--text-muted); line-height: 1.6; }

        /* 页脚 */
        footer { background: #1a1a1a; color: #999; padding: 80px 0; text-align: center; }
        .footer-links { margin-bottom: 30px; }
        .footer-links a { margin: 0 20px; color: #ddd; font-weight: bold; }

        /* --- 移动端核心适配 --- */
        @media (max-width: 768px) {
            /* 下载按钮一行一个 */
            .download-group { 
                flex-direction: column; 
                gap: 20px; 
                align-items: center;
            }
            .btn-dl { 
                width: 100%; 
                max-width: 400px; /* 限制最大宽度，防止太长 */
                font-size: 22px; 
                padding: 18px 0;
            }
            
            .hero-title { font-size: 42px; }
            .hero-subtitle { font-size: 20px; }
            
            .info-inner { flex-direction: column; }
            .steps-container { flex-direction: column; gap: 40px; }
            
            /* 为什么选择区域 手机上一行一个 */
            .features-grid-horizontal { grid-template-columns: 1fr; }
            .feature-img { width: 100%; height: auto; }
            .feature-content { max-width: 100%; }
        }