/* roulang page: index */
:root {
      --primary: #1A5F7A;
      --primary-light: #0E8C8C;
      --accent: #F49E1C;
      --bg: #FAFBFD;
      --white: #FFFFFF;
      --text-title: #0B2B36;
      --text-body: #3A4F5A;
      --text-muted: #7B8F98;
      --border-light: #E5EDF1;
      --radius-sm: 8px;
      --radius-md: 12px;
      --shadow-card: 0 2px 12px rgba(11, 43, 54, 0.06);
      --shadow-hover: 0 8px 24px rgba(11, 43, 54, 0.10);
      --font-title: 'PingFang SC', 'Microsoft YaHei', 'Helvetica Neue', sans-serif;
      --font-body: 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
      --font-mono: 'SF Mono', 'Menlo', 'Monaco', monospace;
      --transition: 0.25s ease;
      --container-max: 1200px;
    }
    * { box-sizing: border-box; }
    body {
      font-family: var(--font-body);
      background-color: var(--bg);
      color: var(--text-body);
      line-height: 1.7;
      margin: 0;
      padding-top: 0;
      font-size: 15px;
    }
    h1, h2, h3, h4, .h1, .h2, .h3 {
      font-family: var(--font-title);
      color: var(--text-title);
      font-weight: 600;
    }
    h1 { font-size: 40px; font-weight: 700; letter-spacing: -0.5px; }
    h2 { font-size: 28px; letter-spacing: 0; }
    h3 { font-size: 18px; }
    p { margin-bottom: 1.2em; color: var(--text-body); }
    a { text-decoration: none; color: inherit; transition: color 0.2s; }
    a:hover { color: var(--primary); }
    .container { max-width: var(--container-max); padding-left: 24px; padding-right: 24px; margin: 0 auto; }

    /* 导航 */
    .navbar {
      padding: 16px 0;
      transition: background 0.3s, box-shadow 0.3s;
      background: transparent;
      z-index: 1030;
    }
    .navbar.scrolled {
      background: rgba(255,255,255,0.98);
      box-shadow: 0 1px 8px rgba(11,43,54,0.06);
      border-bottom: 1px solid var(--border-light);
    }
    .navbar-brand {
      font-family: var(--font-title);
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--primary);
      letter-spacing: 0.5px;
    }
    .nav-link {
      color: var(--text-body) !important;
      font-weight: 500;
      font-size: 15px;
      margin: 0 8px;
      padding: 8px 4px !important;
      position: relative;
      transition: color 0.2s;
    }
    .nav-link:hover, .nav-link.active {
      color: var(--primary) !important;
    }
    .nav-link.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%);
      width: 6px;
      height: 6px;
      background: var(--primary-light);
      border-radius: 50%;
    }
    .btn-cta-nav {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 6px 16px;
      border-radius: 20px;
      font-size: 14px;
      transition: all 0.2s;
      margin-left: 12px;
    }
    .btn-cta-nav:hover {
      background: var(--primary);
      color: white;
    }
    .navbar-toggler { border: none; }
    @media (max-width: 991px) {
      .navbar-collapse { background: white; padding: 20px; border-radius: 12px; margin-top: 10px; box-shadow: var(--shadow-card); }
      .nav-link { margin: 8px 0; }
    }

    /* 按钮系统 */
    .btn-primary-custom {
      background: var(--primary);
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      border: none;
      transition: all 0.2s;
      display: inline-block;
    }
    .btn-primary-custom:hover { background: var(--primary-light); box-shadow: 0 4px 12px rgba(14,140,140,0.3); color: white; }
    .btn-outline-custom {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-sm);
      transition: all 0.2s;
      display: inline-block;
    }
    .btn-outline-custom:hover { background: var(--primary); color: white; }
    .btn-link-arrow {
      color: var(--primary-light);
      font-weight: 500;
      display: inline-flex;
      align-items: center;
      gap: 4px;
      transition: all 0.2s;
    }
    .btn-link-arrow:hover { font-weight: 700; color: var(--primary-light); }

    /* 区块间距 */
    section { padding: 80px 0; }
    @media (max-width: 768px) { section { padding: 48px 0; } }

    /* 卡片 */
    .card-custom {
      background: var(--white);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      border: none;
      transition: all var(--transition);
      height: 100%;
    }
    .card-custom:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-2px);
    }
    .service-card {
      padding: 28px 24px;
      display: flex;
      flex-direction: column;
    }
    .icon-placeholder {
      width: 48px;
      height: 48px;
      background: rgba(26,95,122,0.08);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--primary-light);
      font-weight: 700;
      font-size: 18px;
      margin-bottom: 20px;
    }
    .data-metric {
      font-family: var(--font-mono);
      font-size: 32px;
      font-weight: 700;
      color: var(--primary-light);
    }

    /* progress bar */
    .progress-bar-custom {
      height: 8px;
      background: var(--border-light);
      border-radius: 10px;
      overflow: hidden;
    }
    .progress-fill {
      height: 100%;
      background: linear-gradient(90deg, var(--primary) 0%, var(--primary-light) 100%);
      width: 0%;
      border-radius: 10px;
      transition: width 1.2s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    }

    /* FAQ 手风琴 */
    .faq-category .list-group-item {
      border: none;
      padding: 12px 16px;
      color: var(--text-body);
      font-weight: 500;
      border-left: 3px solid transparent;
      transition: 0.2s;
      cursor: pointer;
    }
    .faq-category .list-group-item.active-cat {
      border-left: 3px solid var(--primary-light);
      color: var(--primary);
      background: rgba(26,95,122,0.04);
      font-weight: 600;
    }
    .accordion-button:not(.collapsed) {
      background: rgba(26,95,122,0.02);
      color: var(--text-title);
      box-shadow: none;
    }
    .accordion-button:focus { box-shadow: none; border-color: var(--border-light); }

    footer {
      background: white;
      padding: 60px 0 30px;
      border-top: 1px solid var(--border-light);
    }
    @media (max-width: 768px) {
      h1 { font-size: 28px; }
      .navbar-brand { font-size: 1.2rem; }
    }