/* roulang page: index */
:root {
      --primary: #1A56DB;
      --primary-dark: #153CC0;
      --primary-light: #EEF2FF;
      --accent: #00A86B;
      --bg: #F8FAFC;
      --white: #FFFFFF;
      --text: #334155;
      --text-muted: #64748B;
      --border: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
      --shadow-md: 0 4px 12px rgba(26,86,219,0.12);
      --shadow-lg: 0 10px 25px rgba(26,86,219,0.15);
      --radius-sm: 8px;
      --radius: 12px;
      --radius-lg: 16px;
      --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, sans-serif;
      --transition: 0.25s ease;
      --container: 1280px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background: var(--bg);
      color: var(--text);
      line-height: 1.6;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: var(--container);
      margin: 0 auto;
      padding: 0 24px;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
      border: none;
      font-weight: 600;
      border-radius: var(--radius-sm);
    }
    h1, h2, h3, h4 {
      font-weight: 700;
      line-height: 1.3;
    }
    h1 {
      font-size: 48px;
      letter-spacing: -0.5px;
    }
    h2 {
      font-size: 36px;
      margin-bottom: 16px;
    }
    h3 {
      font-size: 24px;
    }
    h4 {
      font-size: 18px;
    }
    .section {
      padding: 100px 0;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: var(--white);
      z-index: 1000;
      border-bottom: 1px solid transparent;
      transition: box-shadow 0.3s ease, border-color 0.3s;
    }
    .header.scrolled {
      box-shadow: 0 1px 3px rgba(0,0,0,0.05);
      border-color: var(--border);
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 22px;
      color: var(--primary);
    }
    .logo i {
      font-size: 28px;
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      color: var(--text);
      font-size: 16px;
      position: relative;
    }
    .nav-links a:hover {
      color: var(--primary);
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 28px;
      box-shadow: 0 4px 12px rgba(26,86,219,0.25);
      font-size: 16px;
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      box-shadow: 0 6px 14px rgba(26,86,219,0.35);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 28px;
    }
    .btn-outline:hover {
      background: var(--primary-light);
    }
    .btn-ghost {
      background: transparent;
      color: white;
      border: 2px solid white;
      padding: 12px 28px;
    }
    .btn-ghost:hover {
      background: white;
      color: var(--primary);
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 28px;
      color: var(--text);
      padding: 8px;
    }
    /* Hero */
    .hero {
      padding-top: 140px;
      padding-bottom: 80px;
      background: linear-gradient(180deg, #FFFFFF 0%, #F8FAFC 100%);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 60px;
    }
    .hero-text {
      flex: 1;
      animation: fadeUp 0.8s ease;
    }
    .hero-text h1 {
      margin-bottom: 20px;
      color: #0F172A;
    }
    .hero-text p {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 1;
      animation: float 4s ease-in-out infinite;
    }
    .hero-image img {
      border-radius: var(--radius-lg);
      box-shadow: 0 20px 35px rgba(0,0,0,0.1);
      width: 100%;
    }
    @keyframes fadeUp {
      0% { opacity: 0; transform: translateY(20px); }
      100% { opacity: 1; transform: translateY(0); }
    }
    @keyframes float {
      0% { transform: translateY(0); }
      50% { transform: translateY(-8px); }
      100% { transform: translateY(0); }
    }
    /* 功能卡片 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--white);
      padding: 32px;
      border-radius: var(--radius);
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      text-align: left;
    }
    .feature-card:hover {
      box-shadow: var(--shadow-lg);
      transform: translateY(-4px);
    }
    .feature-icon {
      font-size: 38px;
      color: var(--primary);
      margin-bottom: 20px;
    }
    .feature-card h3 {
      margin-bottom: 12px;
    }
    .feature-card p {
      color: var(--text-muted);
      margin-bottom: 16px;
      font-size: 15px;
    }
    .metric {
      font-weight: 700;
      color: var(--accent);
      font-size: 18px;
    }
    /* 场景图文 */
    .scene-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .scene-row.reverse {
      flex-direction: row-reverse;
    }
    .scene-img, .scene-content {
      flex: 1;
    }
    .scene-img img {
      border-radius: var(--radius);
      box-shadow: var(--shadow-sm);
    }
    .scene-content h3 {
      margin-bottom: 16px;
    }
    /* 案例 */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--white);
      padding: 28px;
      border-radius: var(--radius);
      box-shadow: var(--shadow-sm);
      display: flex;
      gap: 20px;
      align-items: center;
    }
    .case-logo img {
      width: 64px;
      height: 64px;
      object-fit: contain;
      filter: grayscale(1);
      transition: var(--transition);
    }
    .case-card:hover .case-logo img {
      filter: grayscale(0);
    }
    .case-stat {
      font-size: 32px;
      font-weight: 700;
      color: var(--accent);
      margin-bottom: 4px;
    }
    /* 定价 */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .pricing-card {
      background: var(--white);
      padding: 36px 28px;
      border-radius: var(--radius);
      box-shadow: var(--shadow-sm);
      text-align: center;
      border: 2px solid transparent;
    }
    .pricing-card.featured {
      border-color: var(--primary);
      transform: scale(1.03);
      box-shadow: var(--shadow-md);
    }
    .badge {
      background: var(--primary);
      color: white;
      font-size: 13px;
      padding: 4px 14px;
      border-radius: 20px;
      display: inline-block;
      margin-bottom: 16px;
    }
    .price {
      font-size: 48px;
      font-weight: 700;
      color: #0F172A;
      margin: 16px 0;
    }
    .feature-list {
      list-style: none;
      text-align: left;
      margin: 24px 0;
    }
    .feature-list li {
      padding: 8px 0;
      color: var(--text);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .feature-list i {
      color: var(--accent);
    }
    /* FAQ */
    .faq-item {
      background: #F1F5F9;
      border-radius: var(--radius-sm);
      margin-bottom: 12px;
    }
    .faq-question {
      width: 100%;
      background: none;
      border: none;
      padding: 20px;
      font-weight: 600;
      font-size: 16px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text);
    }
    .faq-answer {
      padding: 0 20px 20px;
      display: none;
      color: var(--text-muted);
    }
    .faq-item.active .faq-answer {
      display: block;
    }
    .faq-item.active .fa-chevron-down {
      transform: rotate(180deg);
    }
    /* CTA */
    .cta-band {
      background: var(--primary-light);
      text-align: center;
    }
    .cta-band .btn-primary {
      font-size: 18px;
      padding: 16px 40px;
      margin-top: 24px;
    }
    /* Footer */
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 30px;
      padding: 60px 0;
    }
    .footer-col h4 {
      margin-bottom: 18px;
    }
    .footer-col a {
      display: block;
      color: var(--text-muted);
      margin-bottom: 10px;
    }
    .footer-col a:hover {
      color: var(--primary);
    }
    .footer-bottom {
      border-top: 1px solid var(--border);
      padding: 24px 0;
      display: flex;
      justify-content: space-between;
      align-items: center;
      color: var(--text-muted);
      font-size: 14px;
    }
    .social i {
      font-size: 20px;
      margin-left: 16px;
      color: var(--text-muted);
    }
    .social i:hover {
      color: var(--primary);
    }
    /* 移动菜单 */
    @media (max-width: 1024px) {
      h1 { font-size: 40px; }
      h2 { font-size: 30px; }
      .hero-grid { flex-direction: column; }
    }
    @media (max-width: 768px) {
      .nav-links { display: none; }
      .hamburger { display: block; }
      .mobile-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        height: calc(100vh - 72px);
        background: white;
        flex-direction: column;
        justify-content: center;
        align-items: center;
        gap: 32px;
        display: none;
        z-index: 999;
      }
      .mobile-menu.active {
        display: flex;
      }
      .mobile-menu a {
        font-size: 20px;
        font-weight: 500;
      }
      .features-grid, .pricing-grid, .cases-grid {
        grid-template-columns: 1fr;
      }
      .scene-row, .scene-row.reverse {
        flex-direction: column;
      }
      .footer-grid {
        grid-template-columns: 1fr 1fr;
      }
      .section {
        padding: 60px 0;
      }
    }