/* roulang page: index */
:root {
      --primary: #1A3C5E;
      --primary-hover: #152E4A;
      --accent: #C49A2B;
      --accent-hover: #A88224;
      --bg: #F7F9FC;
      --card-bg: #FFFFFF;
      --text: #2C3E50;
      --text-light: #7B8A9B;
      --border: #E2E8F0;
      --shadow: 0 4px 20px rgba(26,60,94,0.06);
      --shadow-hover: 0 8px 30px rgba(26,60,94,0.12);
      --radius-card: 12px;
      --radius-btn: 8px;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Hiragino Sans GB', sans-serif;
      --container-max: 1200px;
      --nav-height: 64px;
      --mobile-nav-height: 56px;
      --bottom-tab-height: 56px;
      --transition: 0.2s ease;
    }

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

    body {
      font-family: var(--font-sans);
      background-color: var(--bg);
      color: var(--text);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
      padding-bottom: var(--bottom-tab-height); /* 为移动端底部Tab留出空间，桌面端通过媒体查询移除 */
    }

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

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

    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      transition: all var(--transition);
      font-weight: 500;
    }

    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }

    /* 导航栏 - 桌面端 */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: white;
      border-bottom: 1px solid var(--border);
      height: var(--nav-height);
      display: flex;
      align-items: center;
    }

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

    .logo {
      font-size: 20px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 0.5px;
      white-space: nowrap;
    }

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

    .nav-links a {
      font-size: 15px;
      font-weight: 500;
      color: var(--text);
      padding: 8px 0;
      border-bottom: 3px solid transparent;
      transition: color var(--transition), border-color var(--transition);
    }

    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
      border-bottom-color: var(--primary);
    }

    .header-cta {
      background: var(--primary);
      color: white;
      padding: 10px 20px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 14px;
    }
    .header-cta:hover {
      background: var(--primary-hover);
    }

    .hamburger {
      display: none;
      font-size: 24px;
      color: var(--primary);
      background: none;
      border: none;
    }

    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--mobile-nav-height);
      left: 0;
      width: 100%;
      background: white;
      box-shadow: var(--shadow);
      padding: 24px;
      z-index: 99;
      flex-direction: column;
      gap: 16px;
    }
    .mobile-menu a {
      font-size: 18px;
      font-weight: 500;
      color: var(--text);
      padding: 8px 0;
      display: block;
    }
    .mobile-menu .mobile-cta {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 12px;
      border-radius: var(--radius-btn);
      margin-top: 8px;
    }

    /* 底部Tab导航 (移动端) */
    .bottom-tab {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      height: var(--bottom-tab-height);
      background: white;
      border-top: 1px solid var(--border);
      z-index: 100;
      justify-content: space-around;
      align-items: center;
      padding: 4px 0;
    }
    .tab-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      font-size: 12px;
      color: var(--text-light);
      gap: 4px;
      transition: color var(--transition);
    }
    .tab-item i {
      font-size: 20px;
    }
    .tab-item.active {
      color: var(--primary);
    }

    /* 区块通用 */
    section {
      padding: 80px 0;
    }

    .section-title {
      font-size: 28px;
      font-weight: 600;
      color: var(--text);
      margin-bottom: 16px;
      letter-spacing: 0.3px;
    }
    .section-subtitle {
      font-size: 16px;
      color: var(--text-light);
      margin-bottom: 40px;
    }

    /* Hero */
    .hero {
      background: linear-gradient(180deg, #F7F9FC 0%, #FFFFFF 100%);
      padding: 80px 0;
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-content {
      flex: 1;
    }
    .hero h1 {
      font-size: 36px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--primary);
      margin-bottom: 16px;
    }
    .hero p {
      font-size: 18px;
      color: var(--text-light);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 14px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
    }
    .btn-outline {
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 14px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      background: transparent;
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .hero-image {
      flex: 1;
      background: #EFF2F7;
      border-radius: 16px;
      overflow: hidden;
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }

    /* 卡片网格 */
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow);
      transition: box-shadow var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
    }
    .icon-circle {
      width: 48px;
      height: 48px;
      background: rgba(26,60,94,0.08);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 16px;
      color: var(--accent);
      font-size: 24px;
    }
    .card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 8px;
    }
    .card p {
      color: var(--text-light);
      font-size: 16px;
    }

    /* 图文交替区块 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .feature-row.reverse {
      flex-direction: row-reverse;
    }
    .feature-text {
      flex: 1;
    }
    .feature-image {
      flex: 1;
      background: #EFF2F7;
      border-radius: 12px;
      overflow: hidden;
    }
    .feature-image img {
      width: 100%;
      height: auto;
    }

    /* 场景卡片 */
    .scene-card img {
      border-radius: 12px 12px 0 0;
      width: 100%;
      height: 200px;
      object-fit: cover;
      background: #EFF2F7;
    }
    .tag {
      display: inline-block;
      border: 1px solid var(--accent);
      color: var(--accent);
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
      margin-top: 12px;
    }

    /* 案例卡片 */
    .case-card {
      display: flex;
      align-items: center;
      gap: 24px;
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow);
    }
    .case-logo {
      width: 80px;
      height: 80px;
      background: #EFF2F7;
      border-radius: 12px;
      flex-shrink: 0;
    }
    .case-number {
      font-size: 28px;
      font-weight: 700;
      color: var(--primary);
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 16px 0;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-size: 18px;
      font-weight: 500;
      cursor: pointer;
      color: var(--text);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, padding 0.3s ease;
      background: #F4F7FB;
      border-radius: 8px;
      margin-top: 8px;
      color: var(--text-light);
      font-size: 16px;
      padding: 0 16px;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding: 16px;
    }
    .faq-item.open .fa-chevron-down {
      transform: rotate(180deg);
    }

    /* 底部CTA */
    .cta-section {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 80px 0;
    }
    .cta-section h2 {
      font-size: 28px;
      margin-bottom: 16px;
    }
    .btn-accent {
      background: var(--accent);
      color: white;
      padding: 16px 36px;
      border-radius: var(--radius-btn);
      font-weight: 700;
      font-size: 16px;
      margin-top: 24px;
    }
    .btn-accent:hover {
      background: var(--accent-hover);
    }

    /* 页脚 */
    .footer {
      background: #1A2D42;
      color: #CBD5E1;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer a {
      color: #CBD5E1;
    }
    .footer a:hover {
      color: var(--accent);
    }
    .copyright {
      border-top: 1px solid #2D3E50;
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      .container {
        padding: 0 20px;
      }
      .grid-3 {
        grid-template-columns: repeat(2, 1fr);
      }
      .feature-row {
        flex-direction: column;
        gap: 32px;
      }
      .feature-row.reverse {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: repeat(2, 1fr);
      }
    }

    @media (max-width: 640px) {
      .header {
        height: var(--mobile-nav-height);
      }
      .nav-links, .header-cta {
        display: none;
      }
      .hamburger {
        display: block;
      }
      .mobile-menu.show {
        display: flex;
      }
      .bottom-tab {
        display: flex;
      }
      body {
        padding-bottom: var(--bottom-tab-height);
      }
      .grid-3, .grid-2 {
        grid-template-columns: 1fr;
      }
      .hero-grid {
        flex-direction: column;
      }
      .hero h1 {
        font-size: 30px;
      }
      section {
        padding: 60px 0;
      }
      .case-card {
        flex-direction: column;
        align-items: flex-start;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }