/* roulang page: index */
/* ----- 设计变量与重置 ----- */
    :root {
      --primary-deep: #1A1F3A;
      --accent-gold: #C9A96E;
      --bg-light: #FAFBFD;
      --card-white: #FFFFFF;
      --text-primary: #1A1F3A;
      --text-secondary: #4A4F6A;
      --text-muted: #5A5F7A;
      --border-light: #E8EBF0;
      --input-bg: #F5F6FA;
      --input-border: #E0E3EB;
      --radius-card: 12px;
      --radius-btn: 8px;
      --shadow-sm: 0 4px 20px rgba(26,31,58,0.06);
      --shadow-hover: 0 8px 30px rgba(26,31,58,0.12);
      --transition: 0.3s ease;
      --max-width: 1200px;
      --header-height: 72px;
      --section-gap: 100px;
    }

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

    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      background-color: var(--bg-light);
      color: var(--text-primary);
      line-height: 1.75;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }

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

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

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

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

    /* ----- 导航栏（白底平台导航，固定顶部） ----- */
    .site-header {
      position: sticky;
      top: 0;
      z-index: 100;
      height: var(--header-height);
      background: var(--card-white);
      box-shadow: 0 2px 12px rgba(26,31,58,0.04);
      display: flex;
      align-items: center;
    }

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

    .logo {
      font-size: 24px;
      font-weight: 700;
      color: var(--primary-deep);
      letter-spacing: 0.5px;
    }
    .logo span {
      color: var(--accent-gold);
    }

    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }

    .nav-menu a {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-secondary);
      padding: 8px 0;
      border-bottom: 2px solid transparent;
      transition: var(--transition);
    }

    .nav-menu a:hover,
    .nav-menu a.active {
      color: var(--accent-gold);
      border-bottom-color: var(--accent-gold);
    }

    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--primary-deep);
      border-radius: 2px;
      transition: var(--transition);
    }

    /* 移动端导航覆盖层 */
    .mobile-overlay {
      display: none;
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background: var(--primary-deep);
      z-index: 200;
      flex-direction: column;
      align-items: center;
      justify-content: center;
      gap: 40px;
    }
    .mobile-overlay.active {
      display: flex;
    }
    .mobile-overlay .close-btn {
      position: absolute;
      top: 24px;
      right: 24px;
      background: none;
      border: none;
      font-size: 32px;
      color: var(--card-white);
      cursor: pointer;
    }
    .mobile-overlay a {
      font-size: 24px;
      color: var(--card-white);
      font-weight: 500;
    }

    /* ----- 通用板块间距 ----- */
    section {
      padding: var(--section-gap) 0;
    }
    @media (max-width: 768px) {
      section {
        padding: 60px 0;
      }
    }

    /* ----- 标题层级 ----- */
    h1 {
      font-size: 3rem;
      font-weight: 700;
      line-height: 1.3;
      color: var(--primary-deep);
    }
    h2 {
      font-size: 2rem;
      font-weight: 600;
      color: var(--primary-deep);
      margin-bottom: 16px;
    }
    h3 {
      font-size: 1.5rem;
      font-weight: 600;
      color: var(--primary-deep);
    }
    h4 {
      font-size: 1.125rem;
      font-weight: 600;
    }

    /* ----- 按钮系统 ----- */
    .btn {
      display: inline-block;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 16px;
      transition: var(--transition);
      text-align: center;
      cursor: pointer;
      border: none;
    }
    .btn-primary {
      background: var(--primary-deep);
      color: white;
    }
    .btn-primary:hover {
      background: var(--accent-gold);
      color: var(--primary-deep);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary-deep);
      color: var(--primary-deep);
    }
    .btn-outline:hover {
      background: var(--primary-deep);
      color: white;
    }

    /* ----- 卡片基础 ----- */
    .card {
      background: var(--card-white);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
    }

    /* ----- Hero 首屏 ----- */
    .hero {
      min-height: 90vh;
      display: flex;
      align-items: center;
      background: var(--bg-light);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-content h1 {
      margin-bottom: 20px;
    }
    .hero-subtitle {
      font-size: 20px;
      color: var(--text-muted);
      margin-bottom: 16px;
    }
    .hero-desc {
      color: var(--text-secondary);
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image img {
      border-radius: 16px;
      box-shadow: 0 20px 35px rgba(26,31,58,0.1);
      width: 100%;
      height: auto;
    }

    /* 优势板块：非三列等高，错落左图标右文字 */
    .features-grid {
      display: flex;
      flex-direction: column;
      gap: 40px;
      margin-top: 40px;
    }
    .feature-item {
      display: flex;
      gap: 28px;
      align-items: flex-start;
    }
    .feature-icon {
      width: 60px;
      height: 60px;
      background: rgba(201,169,110,0.1);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      color: var(--accent-gold);
      font-size: 28px;
      flex-shrink: 0;
    }
    .feature-text h3 {
      margin-bottom: 8px;
    }

    /* 产品卡片横向交错 */
    .product-grid {
      display: flex;
      flex-direction: column;
      gap: 60px;
      margin-top: 40px;
    }
    .product-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 40px;
      align-items: center;
    }
    .product-row.reverse {
      direction: rtl;
    }
    .product-row.reverse .product-info {
      direction: ltr;
    }
    .product-img {
      border-radius: var(--radius-card);
      overflow: hidden;
      height: 280px;
      box-shadow: var(--shadow-sm);
    }
    .product-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .tags {
      display: flex;
      gap: 10px;
      flex-wrap: wrap;
      margin: 16px 0;
    }
    .tag {
      background: rgba(26,31,58,0.06);
      color: var(--primary-deep);
      padding: 4px 14px;
      border-radius: 20px;
      font-size: 14px;
      font-weight: 500;
    }

    /* 流程横向时间轴 */
    .process-timeline {
      display: flex;
      justify-content: space-between;
      margin-top: 48px;
      position: relative;
      gap: 20px;
    }
    .process-step {
      text-align: center;
      flex: 1;
    }
    .step-number {
      width: 44px;
      height: 44px;
      background: var(--accent-gold);
      color: white;
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin: 0 auto 16px;
      font-weight: 700;
      font-size: 18px;
    }

    /* 案例卡片 + 数据指标 */
    .cases-stats {
      display: flex;
      gap: 40px;
      margin-bottom: 40px;
      justify-content: center;
    }
    .stat-item {
      text-align: center;
    }
    .stat-number {
      font-size: 2.8rem;
      font-weight: 700;
      color: var(--accent-gold);
      line-height: 1.2;
    }
    .case-cards {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
      gap: 30px;
    }

    /* FAQ 手风琴 */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      width: 100%;
      background: transparent;
      border: none;
      padding: 20px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      font-size: 1.125rem;
      font-weight: 600;
      color: var(--primary-deep);
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding: 0;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding-bottom: 20px;
    }

    /* 联系表单 */
    .contact-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 50px;
      margin-top: 40px;
    }
    .contact-form input,
    .contact-form textarea {
      width: 100%;
      background: var(--input-bg);
      border: 1px solid var(--input-border);
      border-radius: var(--radius-btn);
      padding: 12px 16px;
      margin-bottom: 16px;
      font-size: 16px;
      transition: var(--transition);
    }
    .contact-form input:focus,
    .contact-form textarea:focus {
      outline: none;
      border-color: var(--accent-gold);
      box-shadow: 0 0 0 3px rgba(201,169,110,0.15);
    }
    .contact-info p {
      margin-bottom: 12px;
      color: var(--text-secondary);
    }

    /* 页脚 */
    .site-footer {
      background: var(--primary-deep);
      color: #B0B5CC;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr;
      gap: 40px;
    }
    .footer-logo {
      font-size: 24px;
      font-weight: 700;
      color: white;
    }
    .footer-links a {
      display: block;
      color: #C9A96E;
      margin-bottom: 10px;
    }
    .copyright {
      border-top: 1px solid rgba(255,255,255,0.08);
      margin-top: 40px;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }

    /* 响应式 */
    @media (max-width: 1024px) {
      h1 { font-size: 2.4rem; }
      .hero-grid { gap: 30px; }
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: flex; }
      .hero-grid, .product-row, .contact-grid {
        grid-template-columns: 1fr;
      }
      .product-row.reverse { direction: ltr; }
      .process-timeline {
        flex-direction: column;
        align-items: flex-start;
        gap: 24px;
      }
      .footer-grid {
        grid-template-columns: 1fr;
      }
    }