/* roulang page: index */
/* 设计变量与全局重置 */
    :root {
      --primary: #0B3B5E;
      --primary-hover: #092D4A;
      --secondary: #00A86B;
      --secondary-hover: #008F5A;
      --accent: #F5A623;
      --bg-page: #FAFBFD;
      --bg-card: #FFFFFF;
      --bg-subtle: #F0F4F8;
      --text-heading: #0A2A40;
      --text-title: #0B3B5E;
      --text-body: #4A4A4A;
      --text-muted: #7A7A7A;
      --border-light: #E8ECF0;
      --shadow-card: 0 4px 20px rgba(0,0,0,0.04), 0 1px 3px rgba(0,0,0,0.05);
      --shadow-card-hover: 0 12px 32px rgba(0,0,0,0.08);
      --radius-md: 12px;
      --radius-btn: 8px;
      --radius-pill: 50px;
      --transition: 0.25s ease;
      --font-system: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --font-number: "Inter", "Roboto", sans-serif;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    html {
      scroll-behavior: smooth;
    }
    body {
      font-family: var(--font-system);
      background-color: var(--bg-page);
      color: var(--text-body);
      line-height: 1.6;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .number {
      font-family: var(--font-number);
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color var(--transition);
    }
    button {
      font-family: inherit;
      cursor: pointer;
      border: none;
      background: transparent;
    }
    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    /* 导航栏 */
    .navbar {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: white;
      border-bottom: 1px solid var(--border-light);
      z-index: 1000;
      display: flex;
      align-items: center;
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 1.6rem;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 1px;
      white-space: nowrap;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 2rem;
    }
    .nav-links a {
      font-size: 0.95rem;
      font-weight: 500;
      color: var(--text-body);
      padding-bottom: 4px;
      border-bottom: 2px 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);
    }
    .nav-cta {
      background: var(--primary);
      color: white !important;
      padding: 0.6rem 1.5rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: background var(--transition);
      border-bottom: none !important;
    }
    .nav-cta:hover {
      background: var(--primary-hover);
    }
    .hamburger {
      display: none;
      font-size: 1.5rem;
      color: var(--primary);
    }
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: white;
      border-top: 1px solid var(--border-light);
      padding: 1.5rem;
      flex-direction: column;
      gap: 1.2rem;
      z-index: 999;
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
    }
    .mobile-menu a {
      font-size: 1.1rem;
      font-weight: 500;
      color: var(--text-body);
      display: block;
      padding: 0.5rem 0;
    }
    /* 区块通用 */
    section {
      padding: 100px 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }
    h2 {
      font-size: 28px;
      line-height: 36px;
      font-weight: 700;
      color: var(--text-title);
      margin-bottom: 1rem;
    }
    /* 按钮系统 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.875rem 2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: all var(--transition);
      font-size: 1rem;
      border: 1.5px solid transparent;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      border-color: var(--primary-hover);
    }
    .btn-secondary {
      background: transparent;
      color: var(--primary);
      border-color: var(--primary);
    }
    .btn-secondary:hover {
      background: rgba(11,59,94,0.05);
    }
    .btn-accent {
      background: var(--secondary);
      color: white;
      border-color: var(--secondary);
    }
    .btn-accent:hover {
      background: var(--secondary-hover);
      border-color: var(--secondary-hover);
    }
    /* 卡片系统 */
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-card);
      transition: all var(--transition);
      padding: 2rem;
    }
    .card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }
    /* 优势非对称布局 */
    .features-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .feature-wide {
      grid-column: span 2;
      background: linear-gradient(135deg, #F0FDF8 0%, #FFFFFF 70%);
      border-radius: var(--radius-md);
      padding: 2.5rem;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .feature-wide:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }
    .feature-item {
      background: var(--bg-card);
      border-radius: var(--radius-md);
      padding: 2rem;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .feature-item:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }
    /* 标签页 */
    .tab-btn {
      padding: 0.5rem 1.5rem;
      border-radius: var(--radius-pill);
      background: #EDF2F7;
      color: var(--text-body);
      font-weight: 500;
      transition: all var(--transition);
      border: none;
      font-size: 0.95rem;
    }
    .tab-btn.active {
      background: var(--primary);
      color: white;
    }
    .capability-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
      gap: 20px;
      margin-top: 2rem;
    }
    /* 案例卡片 */
    .case-card {
      background: white;
      border-radius: var(--radius-md);
      padding: 1.8rem;
      box-shadow: var(--shadow-card);
      border-left: 4px solid var(--secondary);
      transition: var(--transition);
      min-width: 280px;
      flex-shrink: 0;
    }
    .case-card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }
    .case-stat {
      font-size: 2rem;
      font-weight: 700;
      color: var(--accent);
      line-height: 1.2;
    }
    /* FAQ */
    .faq-item {
      background: white;
      border-bottom: 1px solid var(--border-light);
      padding: 1.2rem 0;
    }
    .faq-question {
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-size: 1.1rem;
      color: var(--text-heading);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-body);
      padding-right: 2rem;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 1rem;
    }
    /* CTA 区块 */
    .cta-section {
      background: rgba(11,59,94,0.03);
    }
    /* 页脚 */
    footer {
      background: #0A2A40;
      color: #B0C4D8;
      padding: 3rem 0 1.5rem;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1.5fr 1.5fr;
      gap: 2rem;
    }
    .footer-bottom {
      border-top: 1px solid rgba(255,255,255,0.1);
      margin-top: 2rem;
      padding-top: 1.5rem;
      text-align: center;
      font-size: 0.9rem;
      color: #8A9CA8;
      background: #061E2E;
    }
    /* 响应式调整 */
    @media (max-width: 1024px) {
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
      }
      .hamburger {
        display: block;
      }
      .features-grid {
        grid-template-columns: 1fr;
      }
      .feature-wide {
        grid-column: span 1;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
      h2 {
        font-size: 22px;
      }
      .hero-text h1 {
        font-size: 28px;
        line-height: 1.3;
      }
    }