/* roulang page: index */
:root {
      --primary-deep: #0F172A;
      --accent-orange: #E43D12;
      --accent-orange-hover: #C8320F;
      --bg-page: #FAFAFA;
      --bg-card: #FFFFFF;
      --bg-dark-section: #0F172A;
      --bg-light-gray: #F2F2F2;
      --text-main: #1A1A1A;
      --text-secondary: #555555;
      --text-muted: #999999;
      --border-light: #E5E7EB;
      --radius-card: 12px;
      --radius-button: 8px;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.06);
      --shadow-card-hover: 0 6px 24px rgba(0,0,0,0.10);
      --transition-smooth: 0.25s ease;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      --max-width: 1280px;
      --header-height: 72px;
    }
    
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-page);
      color: var(--text-main);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    
    .container {
      max-width: var(--max-width);
      margin: 0 auto;
      padding: 0 24px;
    }
    
    /* 栅格系统 */
    .row {
      display: flex;
      flex-wrap: wrap;
      gap: 24px;
    }
    .col-3 { flex: 1 1 calc(33.333% - 24px); }
    .col-4 { flex: 1 1 calc(25% - 24px); }
    
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    
    a {
      text-decoration: none;
      color: inherit;
    }
    
    /* 按钮系统 */
    .btn {
      display: inline-block;
      padding: 14px 32px;
      border-radius: var(--radius-button);
      font-weight: 600;
      font-size: 16px;
      text-align: center;
      transition: background var(--transition-smooth), color var(--transition-smooth), border-color var(--transition-smooth), transform var(--transition-smooth);
      cursor: pointer;
      border: 2px solid transparent;
      line-height: 1.2;
    }
    .btn-primary {
      background: var(--accent-orange);
      color: white;
      border-color: var(--accent-orange);
    }
    .btn-primary:hover {
      background: var(--accent-orange-hover);
      border-color: var(--accent-orange-hover);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary-deep);
      border-color: var(--primary-deep);
    }
    .btn-outline:hover {
      background: var(--primary-deep);
      color: white;
      border-color: var(--primary-deep);
    }
    .btn-white-outline {
      background: transparent;
      color: white;
      border-color: white;
    }
    .btn-white-outline:hover {
      background: white;
      color: var(--primary-deep);
    }
    
    /* 导航 */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: var(--header-height);
      background: rgba(255,255,255,0.85);
      backdrop-filter: blur(10px);
      -webkit-backdrop-filter: blur(10px);
      border-bottom: 1px solid var(--border-light);
      z-index: 1000;
      display: flex;
      align-items: center;
    }
    .header-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-size: 22px;
      font-weight: 700;
      color: var(--primary-deep);
      letter-spacing: 0.5px;
      flex: 1;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
      flex: 2;
      justify-content: center;
    }
    .nav-links a {
      font-size: 15px;
      color: var(--text-secondary);
      font-weight: 500;
      transition: color var(--transition-smooth);
      position: relative;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      width: 0;
      height: 2px;
      bottom: -4px;
      left: 0;
      background: var(--accent-orange);
      transition: width var(--transition-smooth);
    }
    .nav-links a:hover {
      color: var(--accent-orange);
    }
    .nav-links a:hover::after {
      width: 100%;
    }
    .nav-right {
      flex: 1;
      display: flex;
      justify-content: flex-end;
    }
    .hamburger {
      display: none;
      font-size: 24px;
      cursor: pointer;
      color: var(--primary-deep);
    }
    
    /* Hero */
    .hero {
      padding: 120px 0 80px;
      background: linear-gradient(135deg, #FAFAFA 0%, #F2F2F2 100%);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-content {
      flex: 1;
    }
    .hero-content h1 {
      font-size: clamp(36px, 5vw, 52px);
      font-weight: 700;
      color: var(--primary-deep);
      line-height: 1.3;
      margin-bottom: 20px;
    }
    .hero-subtitle {
      font-size: 18px;
      color: var(--text-secondary);
      margin-bottom: 32px;
      line-height: 1.7;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      position: relative;
      border-radius: 16px;
      overflow: hidden;
      box-shadow: 0 20px 35px rgba(0,0,0,0.08);
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    
    /* 通用区块 */
    .section {
      padding: 80px 0;
    }
    .section-dark {
      background: var(--bg-dark-section);
      color: white;
    }
    .section-light-gray {
      background: var(--bg-light-gray);
    }
    .section-title {
      font-size: clamp(28px, 4vw, 36px);
      font-weight: 600;
      color: var(--primary-deep);
      margin-bottom: 16px;
      text-align: center;
    }
    .section-dark .section-title {
      color: white;
    }
    .section-desc {
      font-size: 17px;
      color: var(--text-secondary);
      text-align: center;
      max-width: 680px;
      margin: 0 auto 48px;
    }
    
    /* 卡片 */
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      box-shadow: var(--shadow-card);
      padding: 32px;
      transition: box-shadow var(--transition-smooth), transform var(--transition-smooth);
    }
    .card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-2px);
    }
    
    /* 优势区 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
      gap: 24px;
    }
    .feature-icon {
      font-size: 40px;
      color: var(--accent-orange);
      margin-bottom: 16px;
    }
    
    /* 功能分组 */
    .feature-block {
      display: flex;
      gap: 40px;
      align-items: center;
      margin-bottom: 64px;
    }
    .feature-block.reverse {
      flex-direction: row-reverse;
    }
    .feature-text {
      flex: 1;
    }
    .feature-image {
      flex: 1;
      border-radius: 16px;
      overflow: hidden;
    }
    
    /* 场景交替 */
    .scene-row {
      display: flex;
      gap: 48px;
      align-items: center;
      margin-bottom: 64px;
    }
    .scene-row.reverse {
      flex-direction: row-reverse;
    }
    
    /* 案例卡片 */
    .case-grid {
      display: grid;
      grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
      gap: 24px;
    }
    
    /* 价格卡片 */
    .pricing-grid {
      display: flex;
      gap: 24px;
      justify-content: center;
      flex-wrap: wrap;
    }
    .pricing-card {
      flex: 1 1 280px;
      max-width: 340px;
      background: white;
      border-radius: 16px;
      padding: 36px 28px;
      box-shadow: var(--shadow-card);
      border: 2px solid transparent;
      transition: all var(--transition-smooth);
    }
    .pricing-card.featured {
      border-color: var(--accent-orange);
      box-shadow: 0 12px 28px rgba(228,61,18,0.12);
      transform: scale(1.02);
    }
    
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      background: white;
      padding: 18px 0;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease;
      background: #FAFAFA;
      padding: 0 0;
    }
    
    /* 页脚 */
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 30px;
    }
    
    @media (max-width: 1024px) {
      .container { padding: 0 20px; }
      .hero-grid { flex-direction: column; }
      .feature-block, .scene-row { flex-direction: column; }
      .feature-block.reverse, .scene-row.reverse { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    
    @media (max-width: 768px) {
      .nav-links, .nav-right { display: none; }
      .hamburger { display: block; }
      .mobile-menu.active { display: flex; }
      .header-inner { justify-content: space-between; }
      .pricing-grid { flex-direction: column; align-items: center; }
      .card:hover { transform: none; }
      .section { padding: 60px 0; }
    }
    
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--header-height);
      left: 0;
      width: 100%;
      background: white;
      flex-direction: column;
      padding: 24px;
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
    }