/* roulang page: index */
:root {
      --primary: #0A2540;
      --secondary: #0077B6;
      --accent: #F4A261;
      --bg-light: #F8FAFC;
      --text-body: #1E293B;
      --text-muted: #475569;
      --white: #FFFFFF;
      --card-shadow: 0 4px 20px rgba(0,0,0,0.06);
      --card-shadow-hover: 0 8px 30px rgba(0,0,0,0.10);
      --radius-card: 12px;
      --radius-btn: 8px;
      --transition: 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      margin: 0;
      font-family: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      background-color: var(--white);
      color: var(--text-body);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      color: var(--primary);
      margin: 0 0 0.5em 0;
      line-height: 1.3;
    }
    h1 { font-size: clamp(2.2rem, 5vw, 3rem); }
    h2 { font-size: clamp(1.8rem, 4vw, 2.2rem); }
    h3 { font-size: clamp(1.3rem, 3vw, 1.5rem); }
    p { margin: 0 0 1rem; color: var(--text-muted); }
    a { color: var(--secondary); text-decoration: none; transition: color 0.2s; }
    a:hover { color: var(--accent); }
    img { max-width: 100%; height: auto; display: block; }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .navbar {
      background: var(--white);
      box-shadow: 0 1px 6px rgba(0,0,0,0.05);
      position: sticky;
      top: 0;
      z-index: 50;
      backdrop-filter: blur(8px);
      background: rgba(255,255,255,0.92);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-size: 1.8rem;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 1px;
      white-space: nowrap;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
      font-weight: 500;
    }
    .nav-links a {
      color: var(--text-body);
      font-size: 1rem;
      padding: 0.25rem 0;
      border-bottom: 2px solid transparent;
      transition: 0.2s;
    }
    .nav-links a:hover {
      color: var(--secondary);
      border-bottom-color: var(--secondary);
    }
    .mega-trigger {
      position: relative;
      cursor: pointer;
      display: flex;
      align-items: center;
      gap: 0.3rem;
      color: var(--text-body);
    }
    .mega-panel {
      position: absolute;
      top: 100%;
      right: 0;
      margin-top: 1rem;
      background: var(--white);
      border-radius: var(--radius-card);
      box-shadow: 0 15px 40px rgba(0,0,0,0.12);
      padding: 2rem;
      display: none;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
      min-width: 600px;
      z-index: 100;
    }
    .mega-trigger:hover .mega-panel,
    .mega-trigger:focus-within .mega-panel {
      display: grid;
    }
    .mega-col h4 {
      font-size: 1rem;
      margin-bottom: 0.8rem;
      color: var(--primary);
    }
    .mega-col a {
      display: block;
      padding: 0.3rem 0;
      font-size: 0.9rem;
      color: var(--text-muted);
    }
    .mega-col a:hover { color: var(--secondary); }
    .btn {
      display: inline-block;
      padding: 0.7rem 2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: 0.2s;
      text-align: center;
      border: none;
      cursor: pointer;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
    }
    .btn-primary:hover { background: #0B2F4F; color: white; }
    .btn-outline {
      border: 2px solid var(--secondary);
      color: var(--secondary);
      background: transparent;
    }
    .btn-outline:hover { background: var(--secondary); color: white; }
    .btn-accent {
      background: var(--accent);
      color: var(--primary);
      font-weight: 700;
    }
    .btn-accent:hover { background: #e8893a; }
    /* 汉堡菜单 (纯CSS) */
    #menu-toggle { display: none; }
    .menu-icon {
      display: none;
      font-size: 1.8rem;
      cursor: pointer;
      color: var(--primary);
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .menu-icon { display: block; }
      #menu-toggle:checked ~ .nav-links {
        display: flex;
        flex-direction: column;
        position: absolute;
        top: 72px;
        left: 0;
        width: 100%;
        background: white;
        box-shadow: 0 10px 25px rgba(0,0,0,0.1);
        padding: 1.5rem;
        gap: 1rem;
        z-index: 40;
      }
      .mega-panel {
        position: static;
        grid-template-columns: 1fr;
        min-width: auto;
        box-shadow: none;
        padding: 1rem;
        margin-top: 0;
        display: none;
      }
      .mega-trigger:hover .mega-panel { display: grid; }
    }
    /* 卡片与区块 */
    .section {
      padding: 5rem 0;
    }
    .bg-light { background-color: var(--bg-light); }
    .card {
      background: white;
      border-radius: var(--radius-card);
      box-shadow: var(--card-shadow);
      transition: var(--transition);
      overflow: hidden;
    }
    .card:hover {
      box-shadow: var(--card-shadow-hover);
      transform: translateY(-4px);
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 2rem;
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }
    .grid-4 {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 1.5rem;
      text-align: center;
    }
    @media (max-width: 768px) {
      .grid-2, .grid-3, .grid-4 {
        grid-template-columns: 1fr;
      }
      .grid-4 {
        grid-template-columns: repeat(2, 1fr);
      }
      .section { padding: 3rem 0; }
    }
    .stat-number {
      font-size: 3rem;
      font-weight: 700;
      color: var(--accent);
    }
    .stat-unit {
      font-size: 1.5rem;
      color: var(--primary);
      font-weight: 600;
    }
    /* FAQ 手风琴 */
    details {
      background: white;
      border-radius: 10px;
      padding: 1.2rem;
      margin-bottom: 0.8rem;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
      transition: 0.2s;
    }
    details[open] {
      border-left: 4px solid var(--secondary);
      background: #f0f7ff;
    }
    summary {
      font-weight: 600;
      font-size: 1.1rem;
      color: var(--primary);
      cursor: pointer;
      list-style: none;
      display: flex;
      justify-content: space-between;
      align-items: center;
    }
    summary::-webkit-details-marker { display: none; }
    summary::after {
      content: '\f107';
      font-family: 'Font Awesome 6 Free';
      font-weight: 900;
      color: var(--secondary);
      transition: 0.2s;
    }
    details[open] summary::after { content: '\f106'; }
    .faq-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 1.5rem;
    }
    @media (max-width: 768px) {
      .faq-grid { grid-template-columns: 1fr; }
    }
    /* 表单 */
    .form-input {
      width: 100%;
      padding: 0.9rem;
      border-radius: var(--radius-btn);
      border: 1px solid #e2e8f0;
      background: white;
      font-size: 1rem;
      margin-bottom: 1rem;
    }
    .footer-link:hover { color: var(--secondary); }