/* roulang page: index */
:root {
      --primary: #0A84FF;
      --accent: #FF3B30;
      --dark: #1D1F2C;
      --gray: #5B5F6E;
      --light-bg: #F4F6FA;
      --white: #FFFFFF;
      --success: #30D158;
      --border: #E5E7EB;
      --muted: #8E93A0;
      --radius: 12px;
      --radius-sm: 8px;
      --radius-pill: 20px;
      --radius-lg: 16px;
      --shadow-card: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
      --shadow-hover: 0 10px 25px rgba(0,0,0,0.08), 0 4px 10px rgba(0,0,0,0.04);
      --shadow-nav: 0 1px 3px rgba(0,0,0,0.06);
      --font-sans: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
      --font-number: "Inter", "SF Pro Display", -apple-system, sans-serif;
      --transition: 0.3s ease;
    }
    *, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
    html { scroll-behavior: smooth; }
    body {
      font-family: var(--font-sans);
      font-size: 16px;
      line-height: 1.7;
      color: var(--gray);
      background-color: var(--white);
      -webkit-font-smoothing: antialiased;
    }
    img { display: block; max-width: 100%; height: auto; }
    a { text-decoration: none; color: inherit; }
    button, input, textarea { font: inherit; }
    .container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }

    /* 导航 */
    .header {
      position: fixed; top: 0; left: 0; width: 100%; z-index: 100;
      background: var(--white); border-bottom: 1px solid transparent;
      transition: box-shadow var(--transition), border-color var(--transition);
      height: 64px; display: flex; align-items: center;
    }
    .header.scrolled { box-shadow: var(--shadow-nav); border-color: var(--border); }
    .nav-container {
      display: flex; justify-content: space-between; align-items: center;
      width: 100%; max-width: 1200px; margin: 0 auto; padding: 0 24px;
    }
    .logo {
      font-size: 20px; font-weight: 700; color: var(--dark);
      display: flex; align-items: center; gap: 6px;
    }
    .logo span { color: var(--primary); }
    .nav-links { display: flex; gap: 32px; align-items: center; list-style: none; }
    .nav-links a {
      font-size: 15px; font-weight: 500; color: var(--gray);
      padding: 8px 0; border-bottom: 2px solid transparent;
      transition: color 0.2s, border-color 0.2s;
    }
    .nav-links a:hover, .nav-links a.active { color: var(--primary); border-bottom-color: var(--primary); }
    .hamburger { display: none; flex-direction: column; gap: 5px; cursor: pointer; background: none; border: none; padding: 8px; }
    .hamburger span { width: 24px; height: 2px; background: var(--dark); border-radius: 2px; transition: 0.3s; }

    /* 移动端菜单 */
    .mobile-menu {
      position: fixed; top: 0; right: -100%; width: 280px; height: 100vh;
      background: var(--white); box-shadow: -5px 0 20px rgba(0,0,0,0.1);
      padding: 80px 32px 32px; display: flex; flex-direction: column; gap: 24px;
      transition: right 0.35s ease; z-index: 200;
    }
    .mobile-menu.open { right: 0; }
    .mobile-menu a { font-size: 18px; font-weight: 600; color: var(--dark); padding: 12px 0; border-bottom: 1px solid var(--border); }
    .overlay { position: fixed; inset: 0; background: rgba(0,0,0,0.4); z-index: 150; display: none; }
    .overlay.show { display: block; }

    /* Hero */
    .hero {
      margin-top: 64px; min-height: 85vh; display: flex; align-items: center;
      background: linear-gradient(135deg, rgba(29,31,44,0.75) 0%, rgba(10,132,255,0.2) 100%),
      url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      color: var(--white); position: relative;
    }
    .hero-content { display: flex; flex-wrap: wrap; gap: 40px; align-items: center; width: 100%; }
    .hero-text { flex: 1 1 500px; }
    .hero h1 { font-size: 48px; line-height: 1.15; font-weight: 700; margin-bottom: 24px; color: #FFF; }
    .hero p { font-size: 18px; color: rgba(255,255,255,0.85); margin-bottom: 32px; max-width: 560px; }
    .hero-buttons { display: flex; gap: 16px; flex-wrap: wrap; }
    .btn { display: inline-block; padding: 14px 32px; border-radius: var(--radius-sm); font-weight: 600; font-size: 16px; letter-spacing: 0.02em; cursor: pointer; transition: 0.2s; border: none; }
    .btn-primary { background: var(--accent); color: #FFF; }
    .btn-primary:hover { background: #D63029; box-shadow: 0 4px 12px rgba(255,59,48,0.35); transform: translateY(-1px); }
    .btn-outline { background: transparent; border: 2px solid #FFF; color: #FFF; }
    .btn-outline:hover { background: #FFF; color: var(--dark); }
    .hero-stats {
      flex: 0 0 300px; background: rgba(255,255,255,0.12);
      backdrop-filter: blur(20px); border-radius: var(--radius-lg);
      padding: 28px; border: 1px solid rgba(255,255,255,0.25);
      display: grid; grid-template-columns: 1fr 1fr; gap: 20px;
    }
    .stat-item { text-align: center; }
    .stat-number { font-family: var(--font-number); font-size: 42px; font-weight: 800; color: #FFF; line-height: 1.1; }
    .stat-label { font-size: 14px; color: rgba(255,255,255,0.7); margin-top: 4px; }
    .trend-up { color: var(--success); font-weight: 600; font-size: 13px; }

    /* 通用板块 */
    section { padding: 100px 0; }
    .section-header { text-align: center; margin-bottom: 48px; }
    .section-header h2 { font-size: 36px; font-weight: 700; color: var(--dark); line-height: 1.25; }
    .section-header p { color: var(--gray); margin-top: 16px; max-width: 640px; margin-left: auto; margin-right: auto; }
    .bg-light { background: var(--light-bg); }

    /* 数据看板 */
    .stats-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 24px; }
    .stat-card { background: var(--white); border-radius: var(--radius); padding: 28px 24px; box-shadow: var(--shadow-card); text-align: center; }
    .stat-card .big-number { font-family: var(--font-number); font-size: 48px; font-weight: 800; color: var(--primary); line-height: 1.1; }
    .stat-card .unit { font-size: 20px; font-weight: 600; color: var(--dark); }
    .stat-card .trend { margin-top: 8px; font-size: 14px; display: flex; align-items: center; justify-content: center; gap: 4px; }

    /* 服务网格 3x2 */
    .services-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .service-card { background: var(--white); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px; transition: var(--transition); box-shadow: var(--shadow-card); }
    .service-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
    .service-icon { font-size: 36px; color: var(--primary); margin-bottom: 16px; }
    .service-card h3 { font-size: 20px; font-weight: 600; color: var(--dark); margin-bottom: 8px; }
    .service-card p { color: var(--gray); margin-bottom: 16px; font-size: 15px; }
    .text-link { color: var(--primary); font-weight: 600; display: inline-flex; align-items: center; gap: 4px; }
    .text-link:hover { text-decoration: underline; }

    /* 对比区 */
    .compare-row { display: flex; gap: 24px; align-items: stretch; }
    .compare-card { flex: 1; padding: 32px; border-radius: var(--radius); }
    .compare-old { background: #f0f0f3; color: #8E93A0; border: 1px solid #ddd; }
    .compare-new { background: var(--white); border: 1px solid var(--primary); box-shadow: 0 8px 20px rgba(10,132,255,0.12); }
    .compare-card h3 { font-size: 22px; margin-bottom: 20px; }
    .compare-list { list-style: none; }
    .compare-list li { padding: 10px 0; border-bottom: 1px solid var(--border); display: flex; justify-content: space-between; }

    /* 案例 */
    .cases-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 24px; }
    .case-card { background: var(--white); border-radius: var(--radius); overflow: hidden; box-shadow: var(--shadow-card); transition: var(--transition); }
    .case-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-hover); }
    .case-img { height: 200px; background-size: cover; background-position: center; }
    .case-body { padding: 20px; }
    .case-body h3 { font-size: 20px; color: var(--dark); margin-bottom: 8px; }
    .tag { background: var(--light-bg); color: var(--primary); padding: 4px 12px; border-radius: var(--radius-pill); font-size: 13px; font-weight: 600; }

    /* FAQ */
    .faq-list { max-width: 760px; margin: 0 auto; }
    .faq-item { border-bottom: 1px solid var(--border); }
    .faq-question { width: 100%; background: none; border: none; text-align: left; padding: 20px 0; font-weight: 600; color: var(--dark); font-size: 18px; display: flex; justify-content: space-between; cursor: pointer; }
    .faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease; padding-left: 8px; color: var(--gray); }
    .faq-item.active .faq-answer { max-height: 200px; padding-bottom: 16px; }

    /* 表单 */
    .form-row { display: flex; gap: 40px; background: var(--light-bg); border-radius: var(--radius-lg); padding: 48px; }
    .form-left { flex: 2; }
    .form-right { flex: 1; display: flex; flex-direction: column; justify-content: center; }
    .input, .textarea { width: 100%; padding: 12px 16px; border: 1px solid var(--border); border-radius: var(--radius-sm); margin-bottom: 16px; background: #FFF; }
    .input:focus, .textarea:focus { border-color: var(--primary); box-shadow: 0 0 0 3px rgba(10,132,255,0.15); outline: none; }
    .brand-logos { display: flex; flex-wrap: wrap; gap: 16px; margin-top: 20px; opacity: 0.7; }

    /* CTA 横幅 */
    .cta-banner { background: var(--light-bg); text-align: center; padding: 60px 0; }
    .cta-banner h2 { font-size: 32px; margin-bottom: 20px; color: var(--dark); }

    /* Footer */
    .footer { background: var(--dark); color: #CCC; padding: 60px 0 0; }
    .footer-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 32px; }
    .footer h4 { color: #FFF; margin-bottom: 16px; }
    .footer a { color: #BBB; display: block; margin-bottom: 8px; }
    .footer a:hover { color: #FFF; }
    .copyright { border-top: 1px solid rgba(255,255,255,0.1); margin-top: 40px; padding: 20px 0; font-size: 14px; color: var(--muted); }

    @media (max-width: 1024px) {
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero-content { flex-direction: column; }
      .hero h1 { font-size: 38px; }
      .stats-grid { grid-template-columns: repeat(2, 1fr); }
      .services-grid, .cases-grid { grid-template-columns: repeat(2, 1fr); }
      .compare-row { flex-direction: column; }
      .form-row { flex-direction: column; }
    }
    @media (max-width: 768px) {
      .stats-grid, .services-grid, .cases-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .hero h1 { font-size: 32px; }
    }