/* roulang page: index */
:root {
      --primary: #0F2B5C;
      --primary-light: #183e80;
      --accent: #1E6BFF;
      --accent-glow: #00D2A0;
      --bg-pure: #FFFFFF;
      --bg-soft: #F8FAFC;
      --bg-alt: #F0F4F8;
      --bg-dark: #0A192F;
      --text-main: #1E293B;
      --text-body: #334155;
      --text-muted: #64748B;
      --border-light: #E2E8F0;
      --border-focus: #93C5FD;
      --radius-sm: 8px;
      --radius-md: 12px;
      --radius-lg: 18px;
      --shadow-sm: 0 4px 16px rgba(15, 43, 92, 0.04);
      --shadow-md: 0 8px 24px rgba(15, 43, 92, 0.08);
      --shadow-hover: 0 16px 36px rgba(30, 107, 255, 0.14);
      --transition-smooth: all 0.28s cubic-bezier(0.4, 0, 0.2, 1);
    }

    * {
      box-sizing: border-box;
      scroll-behavior: smooth;
    }

    body {
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      background-color: var(--bg-pure);
      color: var(--text-body);
      line-height: 1.65;
      overflow-x: hidden;
      margin: 0;
      padding: 0;
    }

    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition-smooth);
    }

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

    .container-custom {
      width: 100%;
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 20px;
      padding-right: 20px;
    }

    /* 顶部通栏 */
    .top-bar {
      background-color: var(--primary);
      color: #94A3B8;
      font-size: 0.85rem;
      padding: 8px 0;
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    }
    .top-bar a {
      color: #CBD5E1;
    }
    .top-bar a:hover {
      color: #FFFFFF;
    }

    /* 主导航 */
    .site-nav {
      position: sticky;
      top: 0;
      z-index: 1020;
      background: rgba(255, 255, 255, 0.95);
      backdrop-filter: blur(12px);
      box-shadow: 0 2px 14px rgba(15, 43, 92, 0.06);
      transition: var(--transition-smooth);
    }
    .nav-brand-title {
      font-size: 1.35rem;
      font-weight: 800;
      color: var(--primary);
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
      gap: 10px;
    }
    .brand-badge {
      font-size: 0.72rem;
      background: linear-gradient(135deg, var(--accent), var(--accent-glow));
      color: #fff;
      padding: 2px 8px;
      border-radius: 20px;
      font-weight: 600;
    }
    .nav-link-custom {
      font-weight: 500;
      color: var(--text-body);
      padding: 8px 14px;
      border-radius: var(--radius-sm);
      font-size: 0.95rem;
    }
    .nav-link-custom:hover {
      color: var(--accent);
      background-color: #F1F5F9;
    }

    /* 按钮定制 */
    .btn-brand-primary {
      background-color: var(--accent);
      color: #FFFFFF;
      font-weight: 600;
      padding: 10px 22px;
      border-radius: var(--radius-sm);
      border: 1px solid var(--accent);
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-brand-primary:hover {
      background-color: #1254cc;
      color: #FFFFFF;
      box-shadow: 0 6px 18px rgba(30, 107, 255, 0.3);
      transform: translateY(-2px);
    }
    .btn-brand-outline {
      background-color: transparent;
      color: var(--primary);
      font-weight: 600;
      padding: 10px 22px;
      border-radius: var(--radius-sm);
      border: 1px solid var(--border-light);
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      gap: 8px;
    }
    .btn-brand-outline:hover {
      background-color: #F8FAFC;
      border-color: var(--accent);
      color: var(--accent);
      transform: translateY(-2px);
    }

    /* 通用板块 */
    .content-section {
      padding: 90px 0;
      position: relative;
    }
    .section-header {
      margin-bottom: 50px;
    }
    .section-eyebrow {
      display: inline-block;
      font-size: 0.85rem;
      font-weight: 700;
      text-transform: uppercase;
      letter-spacing: 1px;
      color: var(--accent);
      background: rgba(30, 107, 255, 0.08);
      padding: 4px 14px;
      border-radius: 30px;
      margin-bottom: 12px;
    }
    .section-title {
      font-size: 2.25rem;
      font-weight: 800;
      color: var(--primary);
      letter-spacing: -0.5px;
      margin-bottom: 16px;
      line-height: 1.3;
    }
    .section-subtitle {
      font-size: 1.05rem;
      color: var(--text-muted);
      max-width: 760px;
      margin-left: auto;
      margin-right: auto;
    }

    /* 卡片体系 */
    .tech-card {
      background: #FFFFFF;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
      height: 100%;
    }
    .tech-card:hover {
      border-color: rgba(30, 107, 255, 0.3);
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    /* 辅助色与背景 */
    .bg-soft { background-color: var(--bg-soft); }
    .bg-pure { background-color: var(--bg-pure); }
    .bg-deep { background-color: var(--bg-dark); color: #E2E8F0; }
    .bg-banner {
      background-position: center center;
      background-size: cover;
      position: relative;
    }
    .bg-banner-overlay {
      position: absolute;
      inset: 0;
      background: linear-gradient(135deg, rgba(15, 43, 92, 0.94) 0%, rgba(10, 25, 47, 0.96) 100%);
    }

    /* 板块专属细节 */
    .metric-value {
      font-size: 2.7rem;
      font-weight: 800;
      line-height: 1;
      font-feature-settings: "tnum";
    }
    .badge-metric {
      font-size: 0.75rem;
      background: rgba(0, 210, 160, 0.15);
      color: #00A37A;
      font-weight: 700;
      padding: 3px 8px;
      border-radius: 4px;
    }

    .timeline-item {
      position: relative;
      padding-left: 28px;
      border-left: 2px solid #E2E8F0;
      padding-bottom: 30px;
    }
    .timeline-item::before {
      content: "";
      position: absolute;
      left: -7px;
      top: 4px;
      width: 12px;
      height: 12px;
      border-radius: 50%;
      background: var(--accent);
      border: 2px solid #FFFFFF;
    }
    .timeline-item:last-child {
      border-left-color: transparent;
      padding-bottom: 0;
    }

    .accordion-button:not(.collapsed) {
      color: var(--accent);
      background-color: rgba(30, 107, 255, 0.05);
      box-shadow: none;
    }
    .accordion-button:focus {
      box-shadow: none;
      border-color: var(--border-focus);
    }

    /* 页脚 */
    .site-footer {
      background-color: #061224;
      color: #94A3B8;
      padding: 80px 0 35px;
      border-top: 1px solid rgba(255, 255, 255, 0.06);
    }
    .footer-heading {
      color: #F8FAFC;
      font-size: 1.05rem;
      font-weight: 700;
      margin-bottom: 22px;
    }
    .footer-links {
      list-style: none;
      padding: 0;
      margin: 0;
    }
    .footer-links li {
      margin-bottom: 12px;
    }
    .footer-links a {
      color: #94A3B8;
    }
    .footer-links a:hover {
      color: #FFFFFF;
      padding-left: 4px;
    }

    @media (max-width: 991.98px) {
      .content-section {
        padding: 60px 0;
      }
      .section-title {
        font-size: 1.85rem;
      }
    }