/* 夸克/UC SEM落地页风格 - 单页长滚动、高转化、SEO友好 */
:root {
    --primary: #2b5aed; /* 科技蓝 */
    --accent: #ff5722; /* 下载按钮高亮橙红 */
    --accent-hover: #e64a19;
    --text-main: #333;
    --text-light: #666;
    --bg-light: #f4f7fa;
    --white: #fff;
    --shadow: 0 10px 30px rgba(0,0,0,0.08);
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif; color: var(--text-main); background: var(--white); line-height: 1.6; }
a { text-decoration: none; color: var(--primary); transition: all 0.3s; }
a:hover { color: var(--accent); }
.zdd439container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

/* 头部导航 */
.zdd439header { background: rgba(255,255,255,0.95); backdrop-filter: blur(10px); position: sticky; top: 0; z-index: 1000; box-shadow: 0 2px 10px rgba(0,0,0,0.05); }
.zdd439header_inner { display: flex; align-items: center; justify-content: space-between; height: 70px; }
.zdd439logo { font-size: 24px; font-weight: bold; color: var(--primary); }
.zdd439nav { display: flex; gap: 25px; }
.zdd439nav a { color: var(--text-main); font-size: 15px; font-weight: 500; }
.zdd439nav a:hover, .zdd439nav a.current { color: var(--primary); }
.zdd439btn_dl { background: var(--accent); color: #fff !important; padding: 10px 24px; border-radius: 20px; font-weight: bold; box-shadow: 0 4px 15px rgba(255,87,34,0.3); }
.zdd439btn_dl:hover { background: var(--accent-hover); transform: translateY(-2px); }

/* 首屏 Hero */
.zdd439hero { background: linear-gradient(135deg, #e0eafc 0%, #cfdef3 100%); padding: 80px 0; overflow: hidden; }
.zdd439hero_inner { display: flex; align-items: center; justify-content: space-between; }
.zdd439hero_text { flex: 1; }
.zdd439hero_text h1 { font-size: 42px; color: #1a1a1a; margin-bottom: 20px; line-height: 1.2; }
.zdd439hero_text p { font-size: 18px; color: var(--text-light); margin-bottom: 30px; max-width: 500px; }
.zdd439hero_btns { display: flex; gap: 15px; }
.zdd439hero_btns a { padding: 14px 30px; border-radius: 8px; font-size: 16px; font-weight: bold; display: flex; align-items: center; gap: 8px; }
.zdd439btn_ios { background: #000; color: #fff !important; }
.zdd439btn_android { background: var(--primary); color: #fff !important; }
.zdd439hero_img { flex: 1; text-align: right; }
.zdd439phone_mockup { width: 300px; height: 600px; background: #fff; border-radius: 30px; box-shadow: var(--shadow); display: flex; align-items: center; justify-content: center; color: #ccc; border: 8px solid #333; margin-left: auto; }

/* 核心卖点 */
.zdd439features { padding: 80px 0; background: var(--white); }
.zdd439section_title { text-align: center; margin-bottom: 50px; }
.zdd439section_title h2 { font-size: 32px; color: #1a1a1a; margin-bottom: 10px; }
.zdd439section_title p { color: var(--text-light); font-size: 16px; }
.zdd439features_grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 30px; }
.zdd439feature_card { background: var(--bg-light); padding: 40px 20px; border-radius: 16px; text-align: center; transition: all 0.3s; }
.zdd439feature_card:hover { transform: translateY(-10px); box-shadow: var(--shadow); background: var(--white); }
.zdd439feature_icon { width: 60px; height: 60px; background: var(--primary); border-radius: 50%; margin: 0 auto 20px; display: flex; align-items: center; justify-content: center; color: #fff; font-size: 24px; }
.zdd439feature_card h3 { font-size: 20px; margin-bottom: 15px; }
.zdd439feature_card p { color: var(--text-light); font-size: 14px; }

/* SEO 文章引流区 */
.zdd439seo_section { padding: 60px 0; background: var(--bg-light); }
.zdd439seo_list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 20px; }
.zdd439seo_item { background: var(--white); padding: 20px; border-radius: 8px; display: flex; justify-content: space-between; border-bottom: 1px solid #eee; }
.zdd439seo_item a { color: var(--text-main); flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.zdd439seo_item span { color: #999; font-size: 13px; white-space: nowrap; margin-left: 15px; }

/* 悬浮下载 */
.zdd439fixed_dl { position: fixed; bottom: 30px; right: 30px; width: 60px; height: 60px; background: var(--accent); color: #fff; border-radius: 50%; display: flex; align-items: center; justify-content: center; font-weight: bold; box-shadow: 0 4px 20px rgba(255,87,34,0.4); z-index: 999; animation: pulse 2s infinite; }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 rgba(255,87,34,0.7); } 70% { box-shadow: 0 0 0 15px rgba(255,87,34,0); } 100% { box-shadow: 0 0 0 0 rgba(255,87,34,0); } }

/* 底部 */
.zdd439footer { background: #1a1a1a; color: #aaa; padding: 40px 0; text-align: center; font-size: 14px; }
.zdd439footer a { color: #ddd; margin: 0 10px; }

/* 响应式 */
@media (max-width: 992px) {
    .zdd439features_grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 768px) {
    .zdd439nav { display: none; }
    .zdd439hero_inner { flex-direction: column; text-align: center; }
    .zdd439hero_text h1 { font-size: 28px; }
    .zdd439hero_text p { margin: 0 auto 20px; }
    .zdd439hero_btns { justify-content: center; flex-wrap: wrap; }
    .zdd439hero_img { margin-top: 40px; }
    .zdd439phone_mockup { width: 200px; height: 400px; margin: 0 auto; }
    .zdd439seo_list { grid-template-columns: 1fr; }
}