:root { --primary: #0066FF; --primary-hover: #0052CC; --primary-light: #E6F0FF; --text-main: #1A1A1A; --text-sub: #5C6C80; --text-light: #8C9AAE; --bg-white: #FFFFFF; --bg-gray: #F5F8FF; --bg-footer: #111827; --border: #E2E8F0; --radius-sm: 8px; --radius-md: 12px; --radius-lg: 20px; --container: 1160px; --shadow-sm: 0 2px 8px rgba(0,0,0,0.04); }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body { font-family: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", sans-serif; color: var(--text-main); background: var(--bg-white); line-height: 1.6; -webkit-font-smoothing: antialiased; }
    a { color: var(--primary); text-decoration: none; transition: color 0.2s; }
    a:hover { color: var(--primary-hover); }
    ul { list-style: none; }
    img, svg { max-width: 100%; display: block; height: auto; }
    .container { width: min(100% - 40px, var(--container)); margin-inline: auto; }

    .btn { display: inline-flex; align-items: center; justify-content: center; padding: 0 24px; height: 44px; border-radius: var(--radius-sm); font-size: 15px; font-weight: 600; cursor: pointer; transition: all 0.2s; border: 1px solid transparent; white-space: nowrap; }
    .btn-primary { background: var(--primary); color: #fff; box-shadow: 0 4px 12px rgba(0,102,255,0.2); }
    .btn-primary:hover { background: var(--primary-hover); color: #fff; transform: translateY(-1px); }
    
    /* 导航 */
    .header { position: sticky; top: 0; z-index: 100; background: rgba(255,255,255,0.92); backdrop-filter: blur(12px); border-bottom: 1px solid var(--border); }
    .header-inner { display: flex; align-items: center; justify-content: space-between; height: 72px; }
    .logo img { height: 40px; width: auto; }
    .nav-links { display: flex; gap: 32px; }
    .nav-links a { color: var(--text-main); font-size: 15px; font-weight: 500; }
    .nav-links a:hover, .nav-links a.active { color: var(--primary); }

    /* Hero */
    .hero { padding: 80px 0; background: linear-gradient(135deg, #F8FAFF 0%, #E6F0FF 100%); text-align: center; border-bottom: 1px solid var(--border); }
    .hero h1 { font-size: clamp(32px, 4vw, 52px); font-weight: 800; color: #0B1A30; margin-bottom: 20px; letter-spacing: -1px; }
    .hero p { font-size: 18px; color: var(--text-sub); max-width: 720px; margin: 0 auto; }

    /* 通用区块 */
    .section { padding: 80px 0; }
    .section-gray { background: var(--bg-gray); }
    .section-header { margin-bottom: 40px; width: 100%; }
    .section-header h2 { font-size: 28px; font-weight: 800; color: #0B1A30; margin-bottom: 12px; display: flex; align-items: center; gap: 12px; }
    .section-header h2::before { content: ''; display: inline-block; width: 4px; height: 24px; background: var(--primary); border-radius: 2px; }
    .section-header p { color: var(--text-sub); font-size: 16px; }

    /* FAQ 列表 (宽度与容器对齐) */
    .faq-list { width: 100%; display: flex; flex-direction: column; gap: 16px; }
    details { background: #fff; border: 1px solid var(--border); border-radius: var(--radius-md); width: 100%; transition: box-shadow 0.3s; }
    details:hover { box-shadow: var(--shadow-sm); border-color: #cbd5e1; }
    summary { padding: 20px 24px; font-size: 17px; font-weight: 600; cursor: pointer; list-style: none; display: flex; justify-content: space-between; align-items: center; }
    summary::-webkit-details-marker { display: none; }
    summary::after { content: '+'; font-size: 24px; color: var(--text-sub); font-weight: 400; }
    details[open] summary::after { content: '−'; color: var(--primary); }
    details p { padding: 0 24px 24px; color: var(--text-sub); font-size: 15px; line-height: 1.8; }
    details h3 { font-size: 17px; font-weight: 600; margin: 0; color: var(--text-main); }
    details ol, details ul { padding-left: 20px; margin-top: 10px; }
    details li { margin-bottom: 8px; }

    /* CTA 底部区块 */
    .cta-box { text-align: center; padding: 48px; background: var(--primary-light); border-radius: var(--radius-lg); margin-top: 40px; }
    .cta-box h3 { font-size: 24px; margin-bottom: 12px; color: #0B1A30; }
    .cta-box p { color: var(--text-sub); margin-bottom: 24px; }

    /* Footer */
    .footer { background: var(--bg-footer); color: #94A3B8; padding: 80px 0 32px; }
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 48px; margin-bottom: 64px; }
    .footer-brand img { height: 40px; margin-bottom: 20px; }
    .footer-col h4 { color: #fff; font-size: 15px; margin-bottom: 24px; }
    .footer-col a { color: #94A3B8; font-size: 14px; display: block; margin-bottom: 12px; }
    .footer-col a:hover { color: #fff; }
    .footer-bottom { border-top: 1px solid rgba(255,255,255,0.1); padding-top: 32px; display: flex; justify-content: space-between; font-size: 13px; }

    @media (max-width: 768px) {
      .nav-links { display: none; }
      .footer-grid { grid-template-columns: 1fr; text-align: center; gap: 32px; }
      .footer-brand p { margin: 0 auto; }
      .footer-bottom { flex-direction: column; gap: 16px; text-align: center; }
      summary { padding: 16px 20px; font-size: 16px; }
      details p { padding: 0 20px 20px; }
    }