/* roulang page: index */
:root {
      --primary: #0A1A2F;
      --accent-red: #E63946;
      --accent-orange: #F4A261;
      --bg-light: #F8F9FA;
      --white: #FFFFFF;
      --text-dark: #1E1E1E;
      --text-muted: #5A5A5A;
      --success: #2A9D8F;
      --border-light: #D1D5DB;
      --shadow-card: 0 2px 12px rgba(10, 26, 47, 0.06);
      --shadow-hover: 0 8px 24px rgba(10, 26, 47, 0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --radius-tag: 20px;
      --transition: 0.25s ease;
      --font-system: -apple-system, BlinkMacSystemFont, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --spacing-section: 140px;
      --spacing-group: 56px;
    }

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

    body {
      font-family: var(--font-system);
      background-color: var(--bg-light);
      color: var(--text-dark);
      line-height: 1.75;
      font-weight: 400;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

    h1, h2, h3, h4, .data-number, .metric-value {
      font-family: var(--font-system);
      color: var(--primary);
    }

    h1 {
      font-size: 42px;
      line-height: 1.15;
      font-weight: 800;
      letter-spacing: -0.5px;
    }

    h2 {
      font-size: 32px;
      line-height: 1.25;
      font-weight: 700;
      margin-bottom: 24px;
    }

    h3 {
      font-size: 22px;
      line-height: 1.35;
      font-weight: 600;
    }

    h4 {
      font-size: 16px;
      line-height: 1.4;
      font-weight: 600;
      letter-spacing: 0.5px;
      text-transform: uppercase;
    }

    .text-muted-custom {
      color: var(--text-muted);
      font-size: 16px;
      line-height: 1.75;
    }

    .small-label {
      font-size: 13px;
      font-weight: 500;
      line-height: 1.5;
    }

    .container-custom {
      max-width: 1140px;
      margin: 0 auto;
      padding: 0 20px;
    }

    /* 导航系统 */
    .navbar-custom {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: var(--white);
      border-bottom: 1px solid rgba(10, 26, 47, 0.05);
      z-index: 999;
      display: flex;
      align-items: center;
      transition: var(--transition);
    }

    .nav-container {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }

    .brand-logo {
      font-size: 28px;
      font-weight: 800;
      color: var(--primary);
      letter-spacing: -0.5px;
      display: flex;
      align-items: center;
    }
    .brand-logo .accent-delta {
      color: var(--accent-red);
      font-size: 32px;
      margin-left: 2px;
      line-height: 1;
    }

    .desktop-nav {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-link-anchor {
      color: var(--text-dark);
      font-weight: 500;
      font-size: 15px;
      text-decoration: none;
      position: relative;
      transition: color 0.2s;
    }
    .nav-link-anchor::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-red);
      transition: width 0.25s ease;
    }
    .nav-link-anchor:hover {
      color: var(--accent-red);
    }
    .nav-link-anchor:hover::after {
      width: 100%;
    }

    .btn-primary-custom {
      background: var(--accent-red);
      border: none;
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      transition: all var(--transition);
      text-decoration: none;
      display: inline-block;
      font-size: 15px;
    }
    .btn-primary-custom:hover {
      background: #C62D39;
      transform: scale(1.03);
      color: white;
    }

    .btn-outline-custom {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      transition: all var(--transition);
      text-decoration: none;
      display: inline-block;
      font-size: 15px;
    }
    .btn-outline-custom:hover {
      background: var(--primary);
      color: white;
    }

    /* 移动端底部Tab */
    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 56px;
      background: white;
      box-shadow: 0 -2px 8px rgba(0,0,0,0.04);
      z-index: 1000;
      justify-content: space-around;
      align-items: center;
      border-top: 1px solid #f0f0f0;
    }
    .tab-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      color: #9CA3AF;
      font-size: 10px;
      text-decoration: none;
      transition: color 0.2s;
    }
    .tab-item i {
      font-size: 22px;
      margin-bottom: 2px;
    }
    .tab-item.active {
      color: var(--accent-red);
    }

    /* Hero区域 */
    .hero-section {
      background: linear-gradient(135deg, #0A1A2F 0%, #132B44 100%);
      padding: 160px 0 100px;
      color: white;
      margin-top: 72px;
      position: relative;
      overflow: hidden;
    }
    .hero-metrics {
      display: flex;
      gap: 40px;
      margin: 32px 0 40px;
      flex-wrap: wrap;
    }
    .metric-item {
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .metric-icon {
      color: var(--accent-red);
      font-size: 20px;
    }
    .metric-number {
      font-weight: 800;
      font-size: 24px;
      color: var(--accent-orange);
      letter-spacing: 0.5px;
    }

    /* 服务矩阵 */
    .tag-cloud {
      display: flex;
      flex-wrap: wrap;
      gap: 12px;
      margin-bottom: 40px;
    }
    .tag-pill {
      background: #e9ecef;
      padding: 6px 18px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 500;
      color: var(--primary);
      transition: all 0.2s;
      cursor: default;
    }
    .tag-pill:hover {
      background: var(--accent-red);
      color: white;
    }

    .service-card {
      background: var(--white);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
      height: 100%;
      border-left: 4px solid transparent;
    }
    .service-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
      border-left: 4px solid var(--accent-red);
    }
    .micro-progress {
      height: 6px;
      background: #e9ecef;
      border-radius: 10px;
      margin-top: 16px;
      width: 100%;
    }
    .progress-fill {
      height: 6px;
      border-radius: 10px;
      background: var(--accent-orange);
      width: 78%;
    }

    .data-micro-board {
      background: #f1f4f8;
      border-radius: 8px;
      padding: 20px;
      margin-top: 48px;
    }

    /* Before/After */
    .compare-card {
      background: white;
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-card);
    }
    .compare-bar {
      height: 8px;
      background: #e9ecef;
      border-radius: 4px;
      width: 100%;
      margin: 12px 0;
    }
    .bar-fill-before {
      width: 45%;
      height: 8px;
      background: #ced4da;
      border-radius: 4px;
    }
    .bar-fill-after {
      width: 92%;
      height: 8px;
      background: var(--success);
      border-radius: 4px;
    }

    /* FAQ */
    .accordion-faq .accordion-button {
      font-weight: 600;
      font-size: 16px;
      background: white;
      color: var(--primary);
      box-shadow: none;
      border-left: 3px solid transparent;
      transition: 0.2s;
    }
    .accordion-faq .accordion-button:not(.collapsed) {
      background: #f8f9fc;
      border-left: 3px solid var(--accent-red);
      color: var(--primary);
    }

    /* 表单 */
    .form-control-custom {
      height: 48px;
      border-radius: var(--radius-input);
      border: 1px solid var(--border-light);
      padding: 0 16px;
      font-size: 16px;
    }
    .form-control-custom:focus {
      border-color: var(--accent-red);
      box-shadow: 0 0 0 0.15rem rgba(230,57,70,0.15);
    }

    .contact-dark-card {
      background: var(--primary);
      border-radius: var(--radius-card);
      padding: 32px;
      color: white;
      height: 100%;
    }

    footer {
      background: var(--primary);
      color: rgba(255,255,255,0.8);
      padding: 40px 0;
      text-align: center;
    }

    @media (max-width: 991px) {
      .desktop-nav { display: none; }
      .mobile-bottom-nav { display: flex; }
      .navbar-custom { height: 56px; }
      .hero-section { margin-top: 56px; padding: 120px 0 80px; }
      h1 { font-size: 34px; }
    }

    @media (min-width: 992px) {
      .mobile-bottom-nav { display: none; }
    }