:root {
    --bg-white: #FFFFFF;
    --bg-light: #F4F7F6;
    --primary-blue: #0A58CA; /* 官方可信蓝 */
    --cert-green: #0F9D58; /* 认证绿 */
    --cert-gold: #FFC107;
    --text-dark: #212529;
    --text-body: #495057;
    --text-muted: #6C757D;
    --border-color: #DEE2E6;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: "Microsoft YaHei", -apple-system, sans-serif; background-color: var(--bg-light); color: var(--text-body); line-height: 1.6; }
a { text-decoration: none; color: inherit; transition: 0.2s; }
img { max-width: 100%; display: block; }

/* 顶部认证条 */
.top-cert-bar { background: var(--cert-green); color: #FFF; font-size: 13px; text-align: center; padding: 8px; font-weight: bold; letter-spacing: 1px; display: flex; justify-content: center; align-items: center; gap: 10px; }
.top-cert-bar::before { content: "🛡️"; }

/* 导航 */
.header { background: #FFF; border-bottom: 2px solid var(--border-color); position: sticky; top: 0; z-index: 100; box-shadow: 0 2px 10px rgba(0,0,0,0.02); }
.nav-wrap { max-width: 1200px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; height: 80px; padding: 0 20px; }
.logo { font-size: 24px; font-weight: bold; color: var(--primary-blue); display: flex; align-items: center; gap: 10px; }
.logo img { width: 40px; height: 40px; }
.cert-badge { font-size: 12px; background: rgba(10, 88, 202, 0.1); color: var(--primary-blue); padding: 4px 8px; border-radius: 4px; border: 1px solid var(--primary-blue); margin-left: 10px; font-weight: normal; }
.nav-links { display: flex; gap: 30px; }
.nav-links a { font-weight: 600; color: var(--text-dark); }
.nav-links a:hover, .nav-links a.active { color: var(--primary-blue); }

/* 按钮 */
.btn { display: inline-flex; align-items: center; justify-content: center; padding: 16px 36px; border-radius: 6px; font-size: 18px; font-weight: bold; cursor: pointer; transition: 0.2s; border: 2px solid transparent; }
.btn-primary { background: var(--primary-blue); color: #FFF; box-shadow: 0 4px 15px rgba(10, 88, 202, 0.3); }
.btn-primary:hover { background: #084298; transform: translateY(-2px); }
.btn-outline { background: #FFF; color: var(--primary-blue); border-color: var(--primary-blue); }
.btn-outline:hover { background: #F8FAFF; }
.btn-secure::before { content: "🔒"; margin-right: 8px; font-size: 16px; }

/* 容器 */
.container { max-width: 1200px; margin: 0 auto; padding: 80px 20px; }
.sec-title { text-align: center; font-size: 36px; font-weight: 800; color: var(--text-dark); margin-bottom: 20px; }
.sec-subtitle { text-align: center; font-size: 18px; color: var(--text-muted); margin-bottom: 60px; }

/* Hero */
.hero { background: #FFF; padding: 100px 20px 60px; text-align: center; border-bottom: 1px solid var(--border-color); overflow: hidden; }
.hero-auth { display: inline-flex; align-items: center; gap: 8px; color: var(--cert-green); font-weight: bold; background: rgba(15, 157, 88, 0.1); padding: 6px 16px; border-radius: 20px; margin-bottom: 24px; font-size: 14px; border: 1px solid rgba(15,157,88,0.2); }
.hero h1 { font-size: 56px; font-weight: 900; color: var(--text-dark); margin-bottom: 20px; }
.hero .subtitle { font-size: 24px; color: var(--primary-blue); font-weight: 600; margin-bottom: 40px; }
.hero-btns { display: flex; justify-content: center; gap: 20px; margin-bottom: 60px; }
.hero-img { max-width: 1000px; margin: 0 auto; border: 8px solid #FFF; border-radius: 12px; box-shadow: 0 20px 50px rgba(0,0,0,0.1); position: relative; }
.hero-img::after { content: "✅ 360安全中心官方认证"; position: absolute; top: -15px; right: -15px; background: var(--cert-green); color: #FFF; padding: 8px 16px; border-radius: 20px; font-size: 14px; font-weight: bold; box-shadow: 0 4px 10px rgba(15, 157, 88, 0.4); }

/* 核心卖点 */
.feature-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 20px; }
.f-card { background: #FFF; border: 1px solid var(--border-color); border-radius: 8px; padding: 30px 15px; text-align: center; box-shadow: 0 4px 12px rgba(0,0,0,0.02); }
.f-card img { height: 60px; margin: 0 auto 20px; }
.f-card h3 { font-size: 18px; color: var(--text-dark); margin-bottom: 10px; }
.f-card p { font-size: 13px; color: var(--text-muted); }

/* 功能详情 */
.detail-item { display: flex; align-items: center; gap: 60px; background: #FFF; padding: 50px; border-radius: 12px; border: 1px solid var(--border-color); margin-bottom: 30px; box-shadow: 0 4px 20px rgba(0,0,0,0.03); }
.detail-item:nth-child(even) { flex-direction: row-reverse; }
.d-text { flex: 1; }
.d-auth-tag { display: inline-block; background: var(--cert-gold); color: #000; font-size: 12px; font-weight: bold; padding: 4px 10px; border-radius: 4px; margin-bottom: 15px; }
.d-text h3 { font-size: 32px; color: var(--primary-blue); margin-bottom: 20px; }
.d-text p { font-size: 16px; line-height: 1.8; margin-bottom: 20px; }
.d-data { font-size: 20px; font-weight: bold; color: var(--cert-green); border-left: 4px solid var(--cert-green); padding-left: 15px; }
.d-img { flex: 1; text-align: center; }
.d-img img { border-radius: 8px; border: 1px solid var(--border-color); box-shadow: 0 10px 30px rgba(0,0,0,0.08); display: inline-block; }

/* 浏览器对比 */
.compare-box { background: #FFF; border-radius: 12px; border: 1px solid var(--border-color); overflow: hidden; box-shadow: 0 5px 20px rgba(0,0,0,0.05); }
.compare-table { width: 100%; border-collapse: collapse; text-align: center; }
.compare-table th, .compare-table td { padding: 20px; border-bottom: 1px solid var(--border-color); border-right: 1px solid var(--border-color); }
.compare-table th { background: #F8FAFF; color: var(--text-dark); font-weight: bold; }
.compare-table th:last-child, .compare-table td:last-child { border-right: none; }
.compare-table td.hl { background: rgba(10, 88, 202, 0.03); color: var(--primary-blue); font-weight: bold; }
.compare-table tr:last-child td { border-bottom: none; }

/* 数据背书 */
.data-sec { background: var(--primary-blue); color: #FFF; padding: 80px 0; background-image: radial-gradient(circle at 10% 20%, rgba(255,255,255,0.1) 0%, transparent 40%), radial-gradient(circle at 90% 80%, rgba(255,255,255,0.1) 0%, transparent 40%); }
.data-inner { max-width: 1000px; margin: 0 auto; display: flex; justify-content: space-around; text-align: center; }
.data-item h4 { font-size: 60px; font-weight: 900; margin-bottom: 10px; }
.data-item p { font-size: 18px; opacity: 0.9; }

/* 下载区 */
.dl-wrap { display: flex; gap: 30px; justify-content: center; }
.dl-card { background: #FFF; border: 2px solid var(--border-color); border-radius: 8px; padding: 40px 30px; width: 320px; text-align: center; position: relative; }
.dl-card.official { border-color: var(--primary-blue); box-shadow: 0 10px 30px rgba(10,88,202,0.1); }
.dl-card.official::before { content: "官方主推"; position: absolute; top: -14px; left: 50%; transform: translateX(-50%); background: var(--primary-blue); color: #FFF; padding: 4px 16px; border-radius: 12px; font-size: 13px; font-weight: bold; }
.dl-card h3 { font-size: 24px; color: var(--text-dark); margin-bottom: 15px; }
.dl-card p { font-size: 14px; color: var(--text-muted); margin-bottom: 30px; height: 42px; }
.dl-card .btn { width: 100%; }

/* FAQ */
.faq-list { max-width: 900px; margin: 0 auto; background: #FFF; border: 1px solid var(--border-color); border-radius: 8px; padding: 40px; }
.faq-item { margin-bottom: 30px; }
.faq-item:last-child { margin-bottom: 0; }
.faq-item h4 { font-size: 18px; color: var(--primary-blue); margin-bottom: 10px; display: flex; align-items: center; gap: 10px; }
.faq-item h4::before { content: "Q:"; background: var(--bg-light); padding: 2px 8px; border-radius: 4px; color: var(--text-dark); }
.faq-item p { font-size: 15px; line-height: 1.7; padding-left: 35px; }

/* Footer */
.footer { background: #FFF; border-top: 1px solid var(--border-color); text-align: center; padding: 40px 20px; color: var(--text-muted); font-size: 14px; }
.footer-cert { display: flex; justify-content: center; gap: 20px; margin-bottom: 20px; }
.footer-cert span { display: inline-flex; align-items: center; gap: 5px; }