/* roulang page: index */
:root {
      --primary: #1A8C3E;
      --primary-hover: #147332;
      --primary-soft: rgba(26, 140, 62, 0.08);
      --secondary: #1E1E1E;
      --accent: #F59E0B;
      --bg-warm: #FAF9F6;
      --white: #FFFFFF;
      --text-main: #1E1E1E;
      --text-muted: #5A5A5A;
      --text-light: #8C8C8C;
      --border-light: rgba(0,0,0,0.06);
      --shadow-card: 0 1px 3px rgba(0,0,0,0.04), 0 6px 16px rgba(0,0,0,0.04);
      --shadow-hover: 0 4px 12px rgba(0,0,0,0.08);
      --radius-lg: 16px;
      --radius-md: 12px;
      --radius-sm: 8px;
      --radius-xs: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --transition: 0.2s ease;
      --header-height: 72px;
      --header-height-mobile: 60px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background-color: var(--bg-warm);
      color: var(--text-main);
      line-height: 1.75;
      font-weight: 400;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    .header {
      position: sticky;
      top: 0;
      background: var(--white);
      z-index: 50;
      height: var(--header-height);
      display: flex;
      align-items: center;
      border-bottom: 1px solid transparent;
      transition: box-shadow var(--transition), border-color var(--transition);
    }
    .header.scrolled {
      box-shadow: 0 2px 8px rgba(0,0,0,0.04);
      border-bottom-color: var(--border-light);
    }
    .nav-bar {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 22px;
      letter-spacing: -0.02em;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo i {
      font-size: 24px;
      color: var(--primary);
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-links a {
      font-weight: 500;
      font-size: 15px;
      color: var(--text-main);
      position: relative;
      padding: 8px 0;
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0%;
      height: 2px;
      background: var(--primary);
      transition: width var(--transition);
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 24px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 15px;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      transition: background var(--transition), transform var(--transition);
      white-space: nowrap;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      transform: translateY(-1px);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      padding: 12px 24px;
      border-radius: var(--radius-sm);
      font-weight: 600;
      font-size: 15px;
      transition: background var(--transition), color var(--transition);
    }
    .btn-outline:hover {
      background: var(--primary-soft);
    }
    .menu-toggle {
      display: none;
      font-size: 24px;
      color: var(--text-main);
    }
    /* 移动端菜单 */
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--header-height-mobile);
      left: 0;
      width: 100%;
      background: var(--white);
      flex-direction: column;
      padding: 24px;
      gap: 20px;
      box-shadow: 0 10px 20px rgba(0,0,0,0.05);
      z-index: 40;
      transform: translateY(-10px);
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.2s, transform 0.2s;
    }
    .mobile-menu.open {
      display: flex;
      opacity: 1;
      transform: translateY(0);
      pointer-events: auto;
    }
    /* Hero */
    #hero {
      padding: 80px 0 100px;
      background: var(--bg-warm);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-content h1 {
      font-size: 44px;
      font-weight: 700;
      letter-spacing: -0.02em;
      line-height: 1.2;
      color: var(--secondary);
      margin-bottom: 20px;
    }
    .hero-content .subtitle {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 32px;
    }
    .trust-badges {
      display: flex;
      gap: 24px;
      color: var(--text-muted);
      font-size: 14px;
      font-weight: 500;
    }
    .trust-badges i {
      color: var(--primary);
      margin-right: 6px;
    }
    .hero-image img {
      border-radius: var(--radius-lg);
      box-shadow: var(--shadow-card);
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    /* 板块通用 */
    section {
      padding: 100px 0;
    }
    .section-title {
      font-size: 32px;
      font-weight: 700;
      letter-spacing: -0.02em;
      margin-bottom: 16px;
      color: var(--secondary);
    }
    .section-desc {
      font-size: 18px;
      color: var(--text-muted);
      max-width: 700px;
      margin-bottom: 48px;
    }
    /* 功能卡片 */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--white);
      border-radius: var(--radius-md);
      padding: 32px 24px;
      box-shadow: var(--shadow-card);
      transition: transform var(--transition), box-shadow var(--transition);
      border: 1px solid var(--border-light);
    }
    .feature-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .feature-icon {
      width: 48px;
      height: 48px;
      background: var(--primary-soft);
      border-radius: 50%;
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 24px;
    }
    .feature-card h3 {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 12px;
    }
    .feature-card p {
      color: var(--text-muted);
      font-size: 16px;
    }
    /* 场景卡片 */
    .scenarios-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .scenario-card {
      background: var(--white);
      border-radius: var(--radius-md);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      border-bottom: 3px solid var(--primary);
      transition: box-shadow var(--transition);
    }
    .scenario-card:hover {
      box-shadow: var(--shadow-hover);
    }
    .scenario-img {
      height: 200px;
      object-fit: cover;
    }
    .scenario-text {
      padding: 24px;
    }
    .scenario-text h3 {
      font-size: 20px;
      font-weight: 700;
      margin-bottom: 8px;
    }
    /* 数据区 */
    #stats {
      background: var(--secondary);
      color: white;
      padding: 80px 0;
    }
    .stats-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 32px;
      text-align: center;
    }
    .stat-number {
      font-size: 48px;
      font-weight: 700;
      color: var(--accent);
      line-height: 1.2;
    }
    .stat-label {
      font-size: 14px;
      opacity: 0.75;
      margin-top: 8px;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    details.faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
      transition: background var(--transition);
    }
    details.faq-item[open] {
      background: var(--primary-soft);
      padding: 20px 16px;
      border-radius: var(--radius-sm);
    }
    summary {
      font-weight: 700;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      list-style: none;
      color: var(--text-main);
    }
    summary::-webkit-details-marker {
      display: none;
    }
    .faq-icon {
      font-size: 20px;
      color: var(--primary);
      transition: transform 0.2s;
    }
    details[open] .faq-icon {
      transform: rotate(45deg);
    }
    .faq-answer {
      margin-top: 12px;
      color: var(--text-muted);
    }
    /* CTA */
    #cta {
      background: var(--secondary);
      color: white;
      text-align: center;
      padding: 100px 0;
    }
    #cta h2 {
      color: white;
      font-size: 32px;
      margin-bottom: 16px;
    }
    #cta .sub {
      color: rgba(255,255,255,0.7);
      margin-bottom: 32px;
    }
    .btn-accent {
      background: var(--accent);
      color: #1E1E1E;
      padding: 16px 40px;
      border-radius: var(--radius-sm);
      font-weight: 700;
      font-size: 17px;
      transition: filter var(--transition);
    }
    .btn-accent:hover {
      filter: brightness(1.05);
    }
    /* Footer */
    #footer {
      background: #111;
      color: #ccc;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
      margin-bottom: 40px;
    }
    .footer-logo {
      font-size: 22px;
      font-weight: 700;
      color: white;
      margin-bottom: 12px;
    }
    .footer-desc {
      font-size: 14px;
      color: #aaa;
    }
    .footer-col h4 {
      color: white;
      font-size: 14px;
      font-weight: 700;
      margin-bottom: 16px;
      text-transform: uppercase;
      letter-spacing: 0.04em;
    }
    .footer-col a {
      display: block;
      color: #aaa;
      font-size: 13px;
      margin-bottom: 10px;
    }
    .footer-col a:hover {
      color: white;
    }
    .copyright {
      text-align: center;
      font-size: 13px;
      color: #666;
      border-top: 1px solid #222;
      padding-top: 24px;
    }
    /* 响应式 */
    @media (max-width: 1024px) {
      .features-grid { grid-template-columns: repeat(2, 1fr); }
      .scenarios-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 768px) {
      .header { height: var(--header-height-mobile); }
      .nav-links { display: none; }
      .menu-toggle { display: block; }
      .hero-grid { grid-template-columns: 1fr; gap: 32px; }
      .hero-content h1 { font-size: 32px; }
      .features-grid { grid-template-columns: 1fr; }
      .scenarios-grid { grid-template-columns: 1fr; }
      .stats-grid { grid-template-columns: 1fr 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      section { padding: 70px 0; }
    }