/* roulang page: index */
:root {
      --primary: #1B4F72;
      --primary-hover: #143F5C;
      --accent: #C87A2C;
      --accent-hover: #A86522;
      --bg-light: #F8FAFC;
      --bg-white: #FFFFFF;
      --text-dark: #1A1A1A;
      --text-body: #4A4A4A;
      --text-muted: #6B7280;
      --success: #2D6A4F;
      --border: #E5E7EB;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-md: 0 10px 25px rgba(0,0,0,0.08);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
      --font-number: "Inter", "SF Pro Display", system-ui, sans-serif;
      --max-width: 1280px;
      --header-height: 72px;
    }

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

    body {
      font-family: var(--font-sans);
      color: var(--text-body);
      background: var(--bg-white);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s ease;
    }

    button, input, textarea {
      font-family: inherit;
    }

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

    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 50;
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(12px);
      transition: background 0.3s, box-shadow 0.3s;
    }
    .site-header.scrolled {
      background: var(--bg-white);
      box-shadow: 0 1px 8px rgba(0,0,0,0.06);
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: var(--header-height);
    }
    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary);
      letter-spacing: 0.5px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      list-style: none;
    }
    .nav-links a {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-dark);
      transition: color 0.2s;
    }
    .nav-links a:hover {
      color: var(--accent);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 4px;
      transition: 0.2s;
    }

    /* 版块间距 */
    section {
      padding: 100px 0;
    }

    /* 按钮 */
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      padding: 14px 32px;
      transition: all 0.25s ease;
      border: none;
      cursor: pointer;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-2px);
      box-shadow: var(--shadow-md);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: var(--primary);
      color: white;
    }
    .btn-accent {
      background: var(--accent);
      color: white;
    }
    .btn-accent:hover {
      background: var(--accent-hover);
      transform: translateY(-2px);
      box-shadow: var(--shadow-md);
    }

    /* Hero */
    .hero {
      padding-top: calc(var(--header-height) + 40px);
      background: linear-gradient(180deg, #F8FAFC 0%, #FFFFFF 100%);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-title {
      font-size: 48px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-dark);
      margin-bottom: 20px;
    }
    .hero-sub {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image img {
      border-radius: 16px;
      box-shadow: var(--shadow-md);
    }
    .hero-stats {
      display: flex;
      gap: 40px;
      margin-top: 48px;
      flex-wrap: wrap;
    }
    .stat-number {
      font-family: var(--font-number);
      font-size: 48px;
      font-weight: 700;
      color: var(--accent);
      line-height: 1;
    }
    .stat-label {
      font-size: 14px;
      color: var(--text-muted);
      margin-top: 8px;
    }

    /* 标题层级 */
    .section-title {
      font-size: 32px;
      font-weight: 700;
      color: var(--text-dark);
      margin-bottom: 16px;
    }
    .section-subtitle {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 48px;
    }

    /* 卡片网格 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--bg-white);
      border: 1px solid var(--border);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: all 0.25s ease;
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-md);
    }
    .card-icon {
      font-size: 40px;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .card h3 {
      font-size: 22px;
      font-weight: 600;
      margin-bottom: 12px;
      color: var(--text-dark);
    }

    /* 图文交替 */
    .feature-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      margin-bottom: 80px;
    }
    .feature-row.reverse {
      direction: rtl;
    }
    .feature-row.reverse > * {
      direction: ltr;
    }
    .feature-img img {
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
    }

    /* 场景卡片 */
    .scenario-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .scenario-card {
      background: var(--bg-light);
      border-radius: var(--radius-card);
      padding: 32px;
      transition: 0.25s;
    }
    .scenario-card:hover {
      background: white;
      box-shadow: var(--shadow-md);
    }

    /* 案例卡片 */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-highlight {
      font-size: 36px;
      font-weight: 700;
      color: var(--success);
      font-family: var(--font-number);
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 20px 0;
    }
    .faq-question {
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      color: var(--text-dark);
    }
    .faq-answer {
      font-size: 16px;
      color: var(--text-muted);
      padding-top: 12px;
      display: none;
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active .faq-question {
      color: var(--accent);
    }

    /* CTA 横幅 */
    .cta-band {
      background: var(--primary);
      color: white;
      text-align: center;
      padding: 80px 24px;
      border-radius: var(--radius-card);
      margin: 0 24px;
    }
    .cta-band h2 {
      font-size: 32px;
      margin-bottom: 16px;
    }

    /* 联系表单 */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
    }
    .contact-info p {
      margin-bottom: 16px;
      display: flex;
      align-items: center;
      gap: 12px;
    }
    .form-group {
      margin-bottom: 20px;
    }
    .form-control {
      width: 100%;
      padding: 14px 16px;
      border: 1px solid #D1D5DB;
      border-radius: var(--radius-input);
      font-size: 16px;
      transition: border 0.2s;
    }
    .form-control:focus {
      outline: none;
      border-color: var(--primary);
      box-shadow: 0 0 0 3px rgba(27,79,114,0.1);
    }

    /* 页脚 */
    .site-footer {
      background: #1A1A1A;
      color: #9CA3AF;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: white;
      margin-bottom: 12px;
    }
    .copyright {
      text-align: center;
      padding-top: 40px;
      margin-top: 40px;
      border-top: 1px solid #374151;
    }

    /* 移动端 */
    @media (max-width: 1024px) {
      .card-grid, .scenario-grid, .case-grid {
        grid-template-columns: repeat(2, 1fr);
      }
      .hero-title {
        font-size: 36px;
      }
    }
    @media (max-width: 768px) {
      .nav-links {
        display: none;
        position: absolute;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background: white;
        flex-direction: column;
        padding: 24px;
        box-shadow: var(--shadow-md);
      }
      .nav-links.active {
        display: flex;
      }
      .hamburger {
        display: flex;
      }
      .hero-grid, .feature-row, .contact-grid {
        grid-template-columns: 1fr;
      }
      .card-grid, .scenario-grid, .case-grid {
        grid-template-columns: 1fr;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .hero-stats {
        gap: 24px;
      }
      section {
        padding: 60px 0;
      }
    }