/* roulang page: index */
:root {
      --primary: #E8452D;
      --primary-soft: rgba(232, 69, 45, 0.08);
      --primary-glow: rgba(232, 69, 45, 0.2);
      --deep-blue: #1B2A3B;
      --cool-gray: #F7F8FA;
      --amber: #F5A623;
      --success: #2EAD6F;
      --text-main: #1B2A3B;
      --text-secondary: #4A4A4A;
      --text-muted: #7A7A7A;
      --border-light: #ECEEF2;
      --border-input: #DDE1E8;
      --card-shadow: 0 4px 20px rgba(0, 0, 0, 0.04);
      --card-hover-shadow: 0 12px 32px rgba(0, 0, 0, 0.08);
      --radius-card: 20px;
      --radius-btn: 12px;
      --radius-input: 12px;
      --font-sans: 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', 'Noto Sans SC', sans-serif;
      --font-mono: 'SF Mono', 'Menlo', 'Consolas', monospace;
      --transition-smooth: 0.25s ease;
    }

    * {
      box-sizing: border-box;
    }

    body {
      font-family: var(--font-sans);
      background-color: #FFFFFF;
      color: var(--text-main);
      line-height: 1.6;
      margin: 0;
      -webkit-font-smoothing: antialiased;
      -moz-osx-font-smoothing: grayscale;
    }

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

    @media (max-width: 767px) {
      .container-custom {
        padding-left: 16px;
        padding-right: 16px;
      }
    }

    /* 导航栏 */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 50;
      height: 64px;
      background: rgba(255, 255, 255, 0.92);
      backdrop-filter: blur(12px);
      -webkit-backdrop-filter: blur(12px);
      border-bottom: 1px solid rgba(0, 0, 0, 0.04);
      display: flex;
      align-items: center;
      justify-content: space-between;
      padding: 0 24px;
    }

    .nav-logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 18px;
      color: var(--primary);
      text-decoration: none;
    }

    .nav-logo i {
      font-size: 22px;
      color: var(--primary);
    }

    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
      margin: 0;
      padding: 0;
    }

    .nav-links a {
      text-decoration: none;
      font-size: 14px;
      font-weight: 500;
      color: #333;
      transition: color 0.2s;
      position: relative;
    }

    .nav-links a:hover {
      color: var(--primary);
    }

    .nav-links a.active {
      color: var(--primary);
      font-weight: 600;
    }

    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: -6px;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }

    .search-box {
      display: flex;
      align-items: center;
      background: #F1F3F6;
      border-radius: 18px;
      padding: 6px 16px;
      height: 36px;
      width: 180px;
      color: #8A8A8A;
    }

    .search-box i {
      font-size: 13px;
      margin-right: 8px;
    }

    .search-box span {
      font-size: 13px;
      color: #8A8A8A;
      flex: 1;
    }

    .btn-primary-sm {
      background: var(--primary);
      color: white;
      border: none;
      border-radius: 18px;
      padding: 8px 18px;
      font-weight: 600;
      font-size: 13px;
      cursor: pointer;
      transition: background 0.2s, transform 0.2s;
      white-space: nowrap;
    }

    .btn-primary-sm:hover {
      background: #c93a25;
      transform: scale(1.02);
    }

    .mobile-menu-btn {
      display: none;
      background: none;
      border: none;
      font-size: 24px;
      color: var(--deep-blue);
    }

    @media (max-width: 1023px) {
      .nav-links, .search-box, .desktop-cta {
        display: none;
      }
      .mobile-menu-btn {
        display: block;
      }
    }

    /* 按钮系统 */
    .btn-primary {
      background: var(--primary);
      color: white;
      border: none;
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 15px;
      transition: background 0.2s, transform 0.2s, box-shadow 0.2s;
      display: inline-block;
      text-decoration: none;
      cursor: pointer;
    }

    .btn-primary:hover {
      background: #c93a25;
      transform: translateY(-1px);
      box-shadow: 0 8px 16px rgba(232, 69, 45, 0.25);
    }

    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      border-radius: var(--radius-btn);
      padding: 12px 28px;
      font-weight: 600;
      font-size: 15px;
      transition: all 0.2s;
      display: inline-block;
      text-decoration: none;
    }

    .btn-secondary:hover {
      background: rgba(232, 69, 45, 0.05);
      transform: translateY(-1px);
    }

    /* 卡片与动效 */
    .fade-up {
      opacity: 0;
      transform: translateY(20px);
      transition: opacity 0.5s ease-out, transform 0.5s ease-out;
    }
    .fade-up.visible {
      opacity: 1;
      transform: translateY(0);
    }

    .stat-number {
      font-family: var(--font-mono);
      font-weight: 800;
      font-size: 40px;
      color: var(--primary);
    }

    .service-card {
      background: #fff;
      border-radius: var(--radius-card);
      border: 1px solid var(--border-light);
      padding: 32px;
      transition: all var(--transition-smooth);
    }
    .service-card:hover {
      border-color: rgba(232, 69, 45, 0.3);
      transform: translateY(-6px);
      box-shadow: var(--card-hover-shadow);
    }

    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 500;
      font-size: 18px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.35s ease;
      color: var(--text-muted);
      font-size: 15px;
      line-height: 1.7;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 16px;
    }
    .faq-icon {
      transition: transform 0.2s;
      color: var(--primary);
    }
    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }