* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
        }
        html {
            scroll-behavior: smooth;
        }
        body {
            font-family: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
            background: #ffffff;
            color: #1a1f2e;
            line-height: 1.4;
        }
        .container {
            max-width: 1280px;
            margin: 0 auto;
            padding: 0 32px;
        }
        /* 头部导航 */
        header {
            position: sticky;
            top: 0;
            background: rgba(255,255,255,0.96);
            backdrop-filter: blur(12px);
            z-index: 100;
            border-bottom: 1px solid rgba(0,0,0,0.05);
            padding: 0 24px;
        }
        .header-inner {
            max-width: 1400px;
            margin: 0 auto;
            display: flex;
            align-items: center;
            justify-content: space-between;
            height: 72px;
        }
        .logo {
            display: flex;
            align-items: center;
            gap: 8px;
            font-size: 1.5rem;
            font-weight: 700;
            text-decoration: none;
            color: #0a0b1e;
            letter-spacing: -0.3px;
        }
        .logo-icon {
            width: 32px;
            height: 32px;
            background: linear-gradient(135deg, #2b3bff, #6c5ce7);
            border-radius: 10px;
            display: flex;
            align-items: center;
            justify-content: center;
        }
        nav {
            display: flex;
            gap: 28px;
        }
        nav a {
            text-decoration: none;
            color: #2d3a4b;
            font-weight: 500;
            transition: color 0.2s;
        }
        nav a:hover { color: #2b3bff; }
        .header-btns {
            display: flex;
            gap: 16px;
        }
        .btn-login, .btn-download {
            padding: 8px 20px;
            border-radius: 40px;
            font-weight: 600;
            text-decoration: none;
            transition: all 0.2s;
        }
        .btn-login {
            background: transparent;
            color: #2b3bff;
            border: 1px solid #d0d5dd;
        }
        .btn-login:hover { background: #f5f7ff; border-color: #2b3bff; }
        .btn-download {
            background: #2b3bff;
            color: white;
            box-shadow: 0 2px 6px rgba(43,59,255,0.2);
        }
        .btn-download:hover { background: #1e2ad0; transform: translateY(-1px); }
        .btn-primary {
            background: #2b3bff;
            color: white;
            padding: 12px 32px;
            border-radius: 40px;
            text-decoration: none;
            font-weight: 600;
            display: inline-block;
            transition: all 0.2s;
            box-shadow: 0 8px 20px rgba(43,59,255,0.25);
        }
        .btn-primary:hover { background: #1e2ad0; transform: translateY(-2px); }
        .btn-secondary {
            background: white;
            color: #2b3bff;
            padding: 12px 32px;
            border-radius: 40px;
            text-decoration: none;
            font-weight: 600;
            border: 1px solid #d0d5dd;
            transition: all 0.2s;
        }
        .btn-secondary:hover { background: #f8f9ff; border-color: #2b3bff; }
        /* hero */
        .hero {
            padding: 80px 0 60px;
            background: linear-gradient(145deg, #fafbff 0%, #ffffff 100%);
        }
        .hero-badge {
            background: #eef2ff;
            padding: 6px 14px;
            border-radius: 100px;
            font-size: 0.85rem;
            font-weight: 500;
            display: inline-block;
            margin-bottom: 24px;
            color: #2b3bff;
        }
        h1 {
            font-size: 3.4rem;
            font-weight: 800;
            line-height: 1.2;
            letter-spacing: -0.02em;
            background: linear-gradient(135deg, #0a0b1e, #2b3bff);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
            margin-bottom: 20px;
        }
        .hero-desc {
            font-size: 1.2rem;
            color: #4a5568;
            max-width: 620px;
            margin: 0 auto 32px;
        }
        .hero-btns { display: flex; gap: 20px; justify-content: center; margin-bottom: 60px; flex-wrap: wrap; }
        .browser-window {
            max-width: 900px;
            margin: 0 auto;
            background: #f1f5f9;
            border-radius: 20px;
            overflow: hidden;
            box-shadow: 0 25px 45px -12px rgba(0,0,0,0.2);
        }
        .browser-top { background: #e2e8f0; padding: 12px 16px; display: flex; gap: 8px; }
        .browser-dot { width: 12px; height: 12px; border-radius: 50%; background: #ff5f56; }
        .browser-dot:nth-child(2) { background: #ffbd2e; }
        .browser-dot:nth-child(3) { background: #27c93f; }
        .browser-content { height: 280px; background: linear-gradient(145deg, #ffffff, #f8fafc); position: relative; background-image: radial-gradient(circle at 20% 40%, rgba(43,59,255,0.05) 1px, transparent 1px); background-size: 20px 20px; }
        /* 合作伙伴 */
        .partners { padding: 48px 0; border-bottom: 1px solid #edf2f7; }
        .partners-title { text-align: center; color: #5a6e8a; margin-bottom: 32px; }
        .partners-logos { display: flex; flex-wrap: wrap; justify-content: center; gap: 48px; }
        .partner-logo { font-weight: 600; color: #334155; font-size: 1.1rem; opacity: 0.7; transition: 0.2s; }
        /* 核心功能 (产品介绍区域) */
        .features { padding: 80px 0; background: #ffffff; scroll-margin-top: 80px; }
        .features-header { text-align: center; margin-bottom: 56px; }
        .features-header h2 { font-size: 2.4rem; font-weight: 700; margin-bottom: 12px; }
        .features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 40px; }
        .feature-item { background: #ffffff; padding: 28px; border-radius: 28px; box-shadow: 0 10px 25px -5px rgba(0,0,0,0.05); transition: all 0.25s; border: 1px solid #eef2ff; }
        .feature-item:hover { transform: translateY(-6px); box-shadow: 0 24px 40px -12px rgba(43,59,255,0.15); border-color: #cddcff; }
        .feature-icon { font-size: 2.5rem; margin-bottom: 20px; }
        .feature-item h3 { font-size: 1.5rem; margin-bottom: 12px; }
        .feature-item p { color: #4a5568; line-height: 1.5; }
        /* 深度指纹区块 */
        .bit-deep {
            background: #fefdf8;
            background-image: radial-gradient(circle at 10% 30%, rgba(43,59,255,0.02) 0%, transparent 40%);
            padding: 80px 0;
            border-top: 1px solid #eef2ff;
            border-bottom: 1px solid #eef2ff;
        }
        .intro-wrapper {
            display: flex;
            flex-wrap: wrap;
            gap: 48px;
            align-items: stretch;
        }
        .what-is-bit {
            flex: 1.2;
            background: #ffffff;
            border-radius: 36px;
            padding: 36px 32px;
            box-shadow: 0 20px 35px -12px rgba(0,0,0,0.08);
            border: 1px solid #edf2fa;
        }
        .what-is-bit h2 {
            font-size: 1.9rem;
            margin-bottom: 16px;
            background: linear-gradient(120deg, #1e293b, #2b3bff);
            -webkit-background-clip: text;
            background-clip: text;
            color: transparent;
        }
        .highlight-blue { color: #2b3bff; font-weight: 700; }
        .what-is-bit p { margin-bottom: 20px; line-height: 1.55; color: #2d3e50; }
        .bit-stats-mini { display: flex; gap: 24px; margin: 28px 0 12px; flex-wrap: wrap; }
        .bit-stats-mini div { background: #f1f5f9; padding: 8px 16px; border-radius: 60px; font-size: 0.85rem; font-weight: 500;}
        .fingerprint-params {
            flex: 1.8;
            background: rgba(255,255,255,0.85);
            backdrop-filter: blur(2px);
            border-radius: 36px;
            padding: 32px;
            border: 1px solid rgba(43,59,255,0.15);
            box-shadow: 0 12px 30px rgba(0,0,0,0.05);
        }
        .fingerprint-params h3 { font-size: 1.8rem; font-weight: 700; margin-bottom: 12px; display: flex; align-items: center; gap: 8px; flex-wrap: wrap; }
        .param-badge { font-size: 0.75rem; background: #2b3bff10; padding: 4px 12px; border-radius: 60px; color: #2b3bff; font-weight: 500; }
        .param-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(170px, 1fr)); gap: 18px; margin-top: 24px; }
        .param-card { background: #fafcff; border-radius: 20px; padding: 12px 16px; transition: all 0.2s; border: 1px solid #eef2ff; display: flex; align-items: center; gap: 12px; }
        .param-card:hover { background: #ffffff; border-color: #2b3bff40; transform: scale(1.02);}
        .param-icon { font-size: 1.7rem; width: 40px; text-align: center; }
        .param-info strong { display: block; font-size: 0.9rem; margin-bottom: 4px; color: #0f172a; }
        .param-info span { font-size: 0.7rem; color: #5b6e8c; line-height: 1.3; }
        .finger-note { margin-top: 24px; background: #eef2ff30; border-radius: 24px; padding: 12px 18px; font-size: 0.8rem; text-align: center; color: #2b3bff; }
        /* 价格方案区域 */
        .pricing { padding: 80px 0; background: #ffffff; scroll-margin-top: 80px; }
        .pricing-header { text-align: center; margin-bottom: 56px; }
        .pricing-header h2 { font-size: 2.4rem; font-weight: 700; margin-bottom: 12px; }
        .pricing-grid { display: flex; flex-wrap: wrap; justify-content: center; gap: 32px; }
        .pricing-card { background: #fafcff; border-radius: 36px; padding: 32px 28px; width: 320px; transition: all 0.3s; border: 1px solid #eef2ff; box-shadow: 0 8px 20px rgba(0,0,0,0.02); position: relative; }
        .pricing-card:hover { transform: translateY(-8px); border-color: #cddcff; box-shadow: 0 24px 40px -16px rgba(43,59,255,0.2); }
        .pricing-card.popular { border: 2px solid #2b3bff; background: linear-gradient(145deg, #ffffff, #f9fbff); }
        .popular-badge { position: absolute; top: -12px; right: 24px; background: #2b3bff; color: white; padding: 4px 16px; border-radius: 40px; font-size: 0.75rem; font-weight: 700; }
        .plan-name { font-size: 1.8rem; font-weight: 700; margin-bottom: 12px; }
        .plan-price { font-size: 2.2rem; font-weight: 800; color: #0f172a; margin: 20px 0 8px; }
        .plan-price span { font-size: 1rem; font-weight: 400; color: #5b6e8c; }
        .plan-desc { color: #4a5568; margin-bottom: 24px; font-size: 0.9rem; border-bottom: 1px dashed #e2e8f0; padding-bottom: 16px; }
        .plan-features { list-style: none; margin-bottom: 32px; }
        .plan-features li { padding: 8px 0; display: flex; align-items: center; gap: 10px; font-size: 0.9rem; color: #2d3a4b; }
        .plan-features li::before { content: "✓"; color: #2b3bff; font-weight: 700; }
        .plan-btn { display: block; text-align: center; background: #2b3bff; color: white; padding: 12px; border-radius: 48px; text-decoration: none; font-weight: 600; transition: 0.2s; }
        .plan-btn-outline { background: transparent; border: 1px solid #2b3bff; color: #2b3bff; }
        .plan-btn-outline:hover { background: #2b3bff; color: white; }
        /* 使用场景 */
        .scenarios { padding: 80px 0; background: #fff; scroll-margin-top: 80px; }
        .scenarios-tabs { display: flex; justify-content: center; gap: 20px; margin: 40px 0 32px; flex-wrap: wrap; }
        .scenario-tab { padding: 10px 24px; background: #f1f5f9; border-radius: 60px; cursor: default; font-weight: 500; }
        .scenario-tab.active { background: #2b3bff; color: white; }
        .scenario-features { display: flex; flex-wrap: wrap; gap: 32px; justify-content: center; }
        .scenario-feature { display: flex; gap: 16px; background: #f8fafc; padding: 20px; border-radius: 28px; width: 260px; transition: 0.2s; }
        /* 统计数据 */
        .stats { background: #0a0b1e; color: white; padding: 70px 0; }
        .stats-grid { display: flex; justify-content: space-between; flex-wrap: wrap; gap: 32px; text-align: center; }
        .stat-item h3 { font-size: 2.4rem; font-weight: 800; }
        /* FAQ 区域 (帮助中心) */
        .faq-section { padding: 80px 0; background: #f8faff; scroll-margin-top: 80px; }
        .faq-header { text-align: center; margin-bottom: 48px; }
        .faq-header h2 { font-size: 2.3rem; font-weight: 700; color: #0a0b1e; }
        .faq-header p { color: #4a5568; margin-top: 12px; }
        .faq-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(360px, 1fr)); gap: 28px; }
        .faq-card { background: white; border-radius: 28px; padding: 28px; box-shadow: 0 8px 20px rgba(0,0,0,0.02); border: 1px solid #eef2ff; transition: all 0.2s; }
        .faq-card:hover { transform: translateY(-3px); box-shadow: 0 20px 30px -12px rgba(43,59,255,0.12); border-color: #cddcff; }
        .faq-question { font-size: 1.25rem; font-weight: 700; margin-bottom: 12px; display: flex; align-items: center; gap: 10px; color: #0f172a; }
        .faq-question .q-mark { background: #2b3bff10; width: 28px; height: 28px; display: inline-flex; align-items: center; justify-content: center; border-radius: 30px; color: #2b3bff; font-weight: 800; }
        .faq-answer { color: #475569; line-height: 1.55; font-size: 0.95rem; }
        /* 下载区域 */
        .download { padding: 80px 0; text-align: center; background: #ffffff; scroll-margin-top: 80px; }
        .download-btns { display: flex; flex-wrap: wrap; justify-content: center; gap: 24px; margin-top: 48px; }
        .download-btn { background: white; border-radius: 48px; padding: 12px 28px; display: inline-flex; align-items: center; gap: 16px; text-decoration: none; color: #1e293b; box-shadow: 0 6px 14px rgba(0,0,0,0.05); transition: 0.2s; border: 1px solid #e2e8f0; }
        .download-btn:hover { transform: translateY(-3px); box-shadow: 0 16px 28px rgba(43,59,255,0.15); border-color: #2b3bff; }
        .download-btn-icon svg { width: 32px; height: 32px; }
        .download-btn-text strong { font-size: 1.2rem; display: block; }
        /* footer */
        footer { background: #0f1222; color: #cbd5e1; padding: 56px 0 24px; }
        .footer-content { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 40px; margin-bottom: 48px; }
        .footer-brand { max-width: 280px; }
        .footer-brand .logo { color: white; margin-bottom: 16px; }
        .footer-links h4 { color: white; margin-bottom: 18px; }
        .footer-links ul { list-style: none; }
        .footer-links li a { color: #94a3b8; text-decoration: none; line-height: 2; }
        .footer-bottom { border-top: 1px solid #1e293b; padding-top: 24px; display: flex; justify-content: space-between; flex-wrap: wrap; gap: 16px; }
        @media (max-width: 768px) {
            .container { padding: 0 20px; }
            h1 { font-size: 2.2rem; }
            .header-inner { flex-wrap: wrap; height: auto; padding: 12px 0; gap: 12px; }
            nav { order: 3; width: 100%; justify-content: center; gap: 18px; flex-wrap: wrap; }
            .pricing-grid { gap: 24px; }
            .pricing-card { width: 100%; max-width: 320px; }
            .faq-grid { grid-template-columns: 1fr; }
        }