/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary: #0A2E4D;
      --primary-soft: rgba(10,46,77,0.08);
      --accent: #E85D04;
      --accent-hover: #C94A00;
      --bg-white: #FFFFFF;
      --bg-light: #F4F8FC;
      --text-main: #1A1A1A;
      --text-secondary: #5A5A5A;
      --border-light: #E0E6ED;
      --shadow-card: 0 4px 20px rgba(10,46,77,0.06);
      --shadow-card-hover: 0 8px 30px rgba(10,46,77,0.12);
      --radius-card: 12px;
      --radius-btn: 6px;
      --transition: 0.3s ease;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      background-color: var(--bg-white);
      color: var(--text-main);
      line-height: 1.7;
      font-size: 1rem;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 20px;
    }
    /* 导航栏固定与滚动阴影 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.96);
      backdrop-filter: blur(8px);
      z-index: 50;
      transition: box-shadow 0.3s;
      border-bottom: 1px solid transparent;
    }
    .site-header.scrolled {
      box-shadow: 0 2px 12px rgba(0,0,0,0.04);
      border-bottom-color: var(--border-light);
    }
    .nav-link {
      position: relative;
      font-weight: 500;
      color: var(--text-main);
      padding: 4px 0;
      transition: color 0.2s;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width 0.25s ease;
    }
    .nav-link:hover {
      color: var(--primary);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    /* 按钮系统 */
    .btn-primary {
      background: var(--accent);
      color: white;
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background 0.25s, transform 0.2s;
      border: none;
      cursor: pointer;
      letter-spacing: 0.5px;
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: all 0.25s;
      cursor: pointer;
      letter-spacing: 0.5px;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
      transform: translateY(-1px);
    }
    /* 卡片通用样式 */
    .card {
      background: var(--bg-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      transition: transform 0.3s ease, box-shadow 0.3s ease;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-card-hover);
    }
    /* 装饰标题下划线 */
    .section-title {
      font-size: 2rem;
      font-weight: 700;
      line-height: 1.4;
      text-align: center;
      margin-bottom: 2.5rem;
      position: relative;
      color: var(--text-main);
    }
    .section-title::after {
      content: '';
      display: block;
      width: 50px;
      height: 3px;
      background: var(--primary);
      margin: 12px auto 0;
      border-radius: 2px;
    }
    /* 手风琴动画 */
    .faq-item {
      border: 1px solid var(--border-light);
      border-radius: 8px;
      margin-bottom: 12px;
      background: white;
      overflow: hidden;
    }
    .faq-question {
      width: 100%;
      text-align: left;
      background: transparent;
      border: none;
      padding: 16px 20px;
      font-weight: 600;
      font-size: 1.1rem;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      color: var(--text-main);
      transition: background 0.2s;
    }
    .faq-question:hover {
      background: var(--bg-light);
    }
    .faq-answer {
      padding: 0 20px 16px;
      color: var(--text-secondary);
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active .faq-icon {
      transform: rotate(180deg);
    }
    .faq-icon {
      transition: transform 0.3s ease;
      color: var(--primary);
    }
    /* 移动端汉堡菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 0;
      right: 0;
      width: 75%;
      max-width: 320px;
      height: 100vh;
      background: white;
      box-shadow: -8px 0 24px rgba(0,0,0,0.1);
      z-index: 100;
      padding: 24px;
      transform: translateX(100%);
      transition: transform 0.3s ease;
      flex-direction: column;
    }
    .mobile-menu.open {
      transform: translateX(0);
    }
    .overlay {
      position: fixed;
      inset: 0;
      background: rgba(0,0,0,0.5);
      z-index: 80;
      display: none;
    }
    .overlay.show {
      display: block;
    }
    @media (max-width: 768px) {
      .desktop-nav {
        display: none !important;
      }
      .hamburger-btn {
        display: flex !important;
      }
      .mobile-menu {
        display: flex;
      }
      .hero-content {
        flex-direction: column;
        text-align: center;
      }
      .hero-text {
        order: 1;
      }
      .hero-image {
        order: 0;
        margin-bottom: 24px;
      }
      .stats-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .services-grid {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    .hamburger-btn {
      display: none;
      font-size: 1.8rem;
      background: none;
      border: none;
      color: var(--primary);
      cursor: pointer;
    }
    /* 背景图叠加层 */
    .hero-bg {
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .hero-bg::before {
      content: '';
      position: absolute;
      inset: 0;
      background: linear-gradient(90deg, rgba(10,46,77,0.8) 0%, rgba(10,46,77,0.4) 100%);
    }
    .hero-content {
      position: relative;
      z-index: 2;
    }
    .contact-dark-bg {
      background-image: url('/assets/images/backpic/back-2.webp');
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .contact-dark-bg::before {
      content: '';
      position: absolute;
      inset: 0;
      background: rgba(10,46,77,0.85);
    }