/* roulang page: index */
:root {
      --primary: #1A5F7A;
      --primary-dark: #0E4055;
      --accent: #F27A3A;
      --accent-hover: #E0692A;
      --bg-page: #FAFBFD;
      --bg-card: #FFFFFF;
      --bg-light: #F0F4F8;
      --text-heading: #0B2B3B;
      --text-body: #3D4F5C;
      --text-muted: #6B7D8A;
      --white: #FFFFFF;
      --border: #E2E8ED;
      --shadow-sm: 0 2px 12px rgba(11,43,59,0.06);
      --shadow-md: 0 8px 24px rgba(11,43,59,0.10);
      --radius-lg: 12px;
      --radius-md: 8px;
      --transition: all 0.25s ease;
    }
    * { box-sizing: border-box; }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", "WenQuanYi Micro Hei", sans-serif;
      background: var(--bg-page);
      color: var(--text-body);
      margin: 0;
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    a { text-decoration: none; color: inherit; transition: var(--transition); }
    img { max-width: 100%; height: auto; display: block; }
    .container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }
    h1, h2, h3, h4 { color: var(--text-heading); margin-bottom: 0.5rem; }
    h2 { font-size: 2.25rem; font-weight: 700; margin-bottom: 1rem; position: relative; display: inline-block; }
    h2::after { content: ''; display: block; width: 48px; height: 3px; background: var(--accent); margin-top: 0.5rem; border-radius: 2px; }
    .section { padding: 100px 0; }
    @media (max-width: 1024px) { .section { padding: 70px 0; } h2 { font-size: 2rem; } }
    @media (max-width: 640px) { .section { padding: 60px 0; } h2 { font-size: 1.75rem; } }

    /* 导航 */
    .navbar {
      position: fixed; top: 0; left: 0; width: 100%; z-index: 100;
      background: rgba(250,251,253,0.92); backdrop-filter: blur(12px);
      border-bottom: 1px solid transparent; transition: var(--transition); height: 64px;
    }
    .navbar.scrolled { border-bottom-color: var(--border); box-shadow: 0 2px 8px rgba(0,0,0,0.04); }
    .nav-container { display: flex; align-items: center; justify-content: space-between; height: 64px; max-width: 1200px; margin: 0 auto; padding: 0 20px; }
    .logo { display: flex; align-items: center; font-weight: 700; font-size: 1.25rem; color: var(--text-heading); }
    .logo i { font-size: 1.8rem; color: var(--accent); margin-right: 8px; }
    .nav-links { display: flex; gap: 2rem; list-style: none; margin: 0; }
    .nav-links a { font-size: 0.95rem; font-weight: 500; color: var(--text-body); padding: 6px 0; border-bottom: 2px solid transparent; }
    .nav-links a:hover, .nav-links a.active { color: var(--accent); border-bottom-color: var(--accent); }
    .nav-cta { background: var(--accent); color: white !important; padding: 10px 24px !important; border-radius: var(--radius-md); font-weight: 600; border: none !important; }
    .nav-cta:hover { background: var(--accent-hover); transform: translateY(-1px); }
    .menu-toggle { display: none; background: none; border: none; font-size: 1.8rem; color: var(--text-heading); }
    @media (max-width: 840px) {
      .nav-links { display: none; position: absolute; top: 64px; left: 0; width: 100%; background: white; flex-direction: column; padding: 20px; gap: 1.2rem; box-shadow: var(--shadow-md); }
      .nav-links.active { display: flex; }
      .menu-toggle { display: block; }
    }

    /* Hero 分屏 */
    .hero { padding-top: 64px; min-height: 85vh; display: flex; align-items: center; background: var(--bg-page); }
    .hero-grid { display: flex; align-items: center; gap: 60px; max-width: 1200px; margin: 0 auto; padding: 40px 20px; width: 100%; }
    .hero-content { flex: 0 0 55%; }
    .hero-visual { flex: 0 0 45%; position: relative; border-radius: var(--radius-lg); overflow: hidden; height: 500px; background: var(--primary-dark); }
    .hero-visual img { width: 100%; height: 100%; object-fit: cover; }
    .hero-visual::after { content: ''; position: absolute; inset: 0; background: linear-gradient(135deg, rgba(26,95,122,0.3) 0%, rgba(14,64,85,0.5) 100%); }
    .hero h1 { font-size: 3rem; font-weight: 700; line-height: 1.2; margin-bottom: 1.2rem; }
    .hero p { font-size: 1.1rem; color: var(--text-muted); max-width: 90%; margin-bottom: 2rem; }
    .btn-group { display: flex; gap: 16px; flex-wrap: wrap; }
    .btn-primary { background: var(--accent); color: white; padding: 14px 32px; border-radius: var(--radius-md); font-weight: 600; display: inline-block; border: none; }
    .btn-primary:hover { background: var(--accent-hover); transform: translateY(-2px); box-shadow: var(--shadow-md); color: white; }
    .btn-outline { border: 2px solid var(--primary); color: var(--primary); padding: 14px 32px; border-radius: var(--radius-md); font-weight: 600; background: transparent; }
    .btn-outline:hover { background: var(--primary); color: white; }
    .trust-badge { margin-top: 1.8rem; font-size: 0.9rem; color: var(--text-muted); display: flex; gap: 20px; flex-wrap: wrap; }
    @media (max-width: 1024px) {
      .hero-grid { gap: 30px; }
      .hero-content { flex: 0 0 50%; }
      .hero-visual { flex: 0 0 50%; height: 400px; }
      .hero h1 { font-size: 2.4rem; }
    }
    @media (max-width: 640px) {
      .hero-grid { flex-direction: column-reverse; gap: 30px; }
      .hero-content, .hero-visual { flex: auto; width: 100%; }
      .hero-visual { height: 280px; }
      .hero h1 { font-size: 2rem; }
    }

    /* 卡片通用 */
    .card { background: var(--bg-card); border-radius: var(--radius-lg); border: 1px solid var(--border); box-shadow: var(--shadow-sm); transition: var(--transition); }
    .card:hover { transform: translateY(-6px); box-shadow: var(--shadow-md); border-color: var(--accent); }
    .features-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
    .feature-card { padding: 32px 24px; text-align: center; }
    .feature-card i { font-size: 2.5rem; color: var(--accent); margin-bottom: 1.2rem; }
    .services-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 28px; }
    .service-card { display: flex; flex-direction: column; }
    .service-img { height: 200px; background-size: cover; background-position: center; border-radius: var(--radius-lg) var(--radius-lg) 0 0; }
    .service-body { padding: 28px; flex:1; }
    .data-grid { display: grid; grid-template-columns: repeat(4, 1fr); text-align: center; background: var(--bg-light); border-radius: var(--radius-lg); padding: 40px 20px; }
    .cases-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .case-card { padding: 0; overflow: hidden; }
    .case-img { height: 160px; background: #e9edf2; display: flex; align-items: center; justify-content: center; }
    .case-body { padding: 24px; }
    .tag { background: #eef3f7; color: var(--primary); padding: 4px 12px; border-radius: 20px; font-size: 0.8rem; margin-right: 8px; }
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2,1fr); }
      .services-grid { grid-template-columns: repeat(2,1fr); }
      .cases-grid { grid-template-columns: repeat(2,1fr); }
      .data-grid { grid-template-columns: repeat(2,1fr); gap: 30px; }
    }
    @media (max-width: 640px) {
      .features-grid, .services-grid, .cases-grid { grid-template-columns: 1fr; }
      .data-grid { grid-template-columns: 1fr 1fr; }
    }

    .faq-item { border-bottom: 1px solid var(--border); }
    .faq-question { background: white; padding: 20px; font-weight: 600; display: flex; justify-content: space-between; cursor: pointer; }
    .faq-answer { padding: 0 20px 20px; display: none; color: var(--text-body); }
    .faq-item.active .faq-answer { display: block; }

    .cta-banner { background: linear-gradient(135deg, var(--primary) 0%, var(--primary-dark) 100%); padding: 80px 20px; text-align: center; color: white; border-radius: 0; }
    .footer { background: #0B2B3B; color: #BCC8D0; padding: 60px 20px 30px; }
    .footer-grid { display: grid; grid-template-columns: 2fr 1fr 1.5fr 1fr; gap: 40px; max-width: 1200px; margin: 0 auto; }
    .footer a { color: #BCC8D0; }
    .footer a:hover { color: var(--accent); }
    @media (max-width: 768px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
    @media (max-width: 480px) { .footer-grid { grid-template-columns: 1fr; } }