/* roulang page: index */
:root {
      --primary: #1A3C6D;
      --primary-dark: #0F2A4A;
      --accent: #C8A45C;
      --accent-hover: #B8933E;
      --bg: #FAFBFD;
      --card-bg: #FFFFFF;
      --text-main: #1E293B;
      --text-muted: #64748B;
      --text-heading: #0F172A;
      --success: #0D9488;
      --danger: #B91C1C;
      --border-light: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.06);
      --shadow-md: 0 8px 24px rgba(26,60,109,0.10);
      --radius-card: 16px;
      --radius-btn: 8px;
      --radius-sm: 10px;
      --font-sans: 'Inter', 'Noto Sans SC', system-ui, -apple-system, sans-serif;
    }

    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text-main);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    img {
      max-width: 100%;
      height: auto;
      display: block;
    }

    a {
      color: inherit;
      text-decoration: none;
    }

    button, input {
      font-family: inherit;
    }

    .container {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 24px;
      padding-right: 24px;
    }

    /* 导航卡片面板 */
    .nav-panel {
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      border-radius: 14px;
      box-shadow: 0 2px 8px rgba(0,0,0,0.04), 0 6px 16px rgba(0,0,0,0.06);
      padding: 8px 20px;
      display: flex;
      align-items: center;
      justify-content: space-between;
      transition: all 0.25s ease;
      border: 1px solid rgba(226,232,240,0.6);
    }

    .nav-panel.scrolled {
      background: #FFFFFF;
      box-shadow: 0 6px 20px rgba(0,0,0,0.08);
      border-color: #E2E8F0;
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 6px;
      flex-wrap: wrap;
    }

    .nav-item {
      padding: 8px 16px;
      border-radius: 8px;
      font-weight: 500;
      font-size: 15px;
      color: var(--text-main);
      transition: background 0.2s, color 0.2s;
      white-space: nowrap;
    }

    .nav-item:hover {
      background: #F1F5F9;
      color: var(--primary);
    }

    .btn-primary {
      background: var(--accent);
      color: white;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      cursor: pointer;
      transition: all 0.25s;
      display: inline-block;
      text-align: center;
      box-shadow: 0 4px 10px rgba(200,164,92,0.25);
      letter-spacing: 0.3px;
      font-size: 16px;
    }

    .btn-primary:hover {
      background: var(--accent-hover);
      transform: translateY(-2px);
      box-shadow: 0 12px 20px rgba(200,164,92,0.35);
    }

    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      cursor: pointer;
      transition: all 0.25s;
      display: inline-block;
      text-align: center;
    }

    .btn-outline:hover {
      background: var(--primary);
      color: white;
      transform: translateY(-2px);
      box-shadow: 0 8px 18px rgba(26,60,109,0.2);
    }

    .section-spacing {
      padding-top: 120px;
      padding-bottom: 120px;
    }

    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      border: 1px solid var(--border-light);
      transition: all 0.3s ease;
    }

    .card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }

    .feature-card-left-line {
      border-left: 4px solid var(--primary);
      padding-left: 24px;
      background: var(--card-bg);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
    }

    .accordion-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }

    .accordion-question {
      font-weight: 600;
      cursor: pointer;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text-heading);
    }

    .accordion-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      color: var(--text-muted);
      font-size: 15px;
    }

    .accordion-item.active .accordion-answer {
      max-height: 200px;
      padding-top: 12px;
    }

    .pricing-card.recommended {
      border: 2px solid var(--accent);
      transform: translateY(-8px);
      box-shadow: 0 20px 32px rgba(200,164,92,0.18);
    }

    @media (max-width: 1024px) {
      .section-spacing {
        padding-top: 80px;
        padding-bottom: 80px;
      }
      .nav-links {
        gap: 2px;
      }
    }

    @media (max-width: 768px) {
      .container {
        padding-left: 20px;
        padding-right: 20px;
      }
      .nav-panel {
        flex-wrap: wrap;
      }
      .nav-links {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
      .nav-panel.mobile-open .nav-links {
        display: flex;
        flex-direction: column;
        width: 100%;
        margin-top: 12px;
      }
    }

    .mobile-menu-btn {
      display: none;
      font-size: 28px;
      background: none;
      border: none;
      color: var(--primary);
    }

    @media (max-width: 768px) {
      .mobile-menu-btn {
        display: block;
      }
    }