/* roulang page: index */
:root {
      --primary: #0F4C81;
      --primary-dark: #0A3A62;
      --accent: #F39C12;
      --bg-page: #FAFBFD;
      --bg-white: #FFFFFF;
      --bg-light: #F0F4FA;
      --text-heading: #1A2B4C;
      --text-body: #4A5568;
      --text-muted: #718096;
      --border: #E2E8F0;
      --shadow-card: 0 2px 12px rgba(15, 76, 129, 0.06);
      --shadow-hover: 0 8px 24px rgba(15, 76, 129, 0.12);
      --radius: 12px;
      --radius-btn: 8px;
      --transition: 0.25s ease;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-number: "Inter", "SF Pro Display", sans-serif;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-sans);
      background: var(--bg-page);
      color: var(--text-body);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    .container {
      max-width: 1200px;
      margin: 0 auto;
      padding: 0 24px;
    }
    h1, h2, h3 {
      color: var(--text-heading);
      font-weight: 700;
    }
    h1 {
      font-size: 44px;
      line-height: 1.25;
      letter-spacing: -0.5px;
    }
    h2 {
      font-size: 32px;
      margin-bottom: 16px;
      line-height: 1.3;
    }
    h3 {
      font-size: 18px;
      margin-bottom: 8px;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: var(--transition);
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    button, .btn {
      cursor: pointer;
      font-family: var(--font-sans);
      font-weight: 600;
      border: none;
      outline: none;
      transition: var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      gap: 8px;
    }
    /* 导航 */
    .header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: var(--bg-white);
      box-shadow: 0 1px 8px rgba(0,0,0,0.02);
      z-index: 100;
      height: 64px;
      display: flex;
      align-items: center;
    }
    .nav {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo {
      font-weight: 700;
      font-size: 20px;
      color: var(--primary);
      letter-spacing: 1px;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      color: var(--text-body);
      font-weight: 500;
      position: relative;
      padding: 4px 0;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a::after {
      content: '';
      position: absolute;
      bottom: -3px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--primary);
      transition: width 0.2s;
    }
    .nav-links a:hover::after,
    .nav-links a.active::after {
      width: 100%;
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      background: none;
      border: none;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--text-heading);
      transition: 0.3s;
    }
    .mobile-menu {
      display: none;
    }
    /* 通用区块 */
    section {
      padding: 100px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 60px;
    }
    .btn-primary {
      background: var(--primary);
      color: #fff;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      box-shadow: 0 4px 10px rgba(15,76,129,0.2);
    }
    .btn-primary:hover {
      background: var(--primary-dark);
      transform: translateY(-2px);
      box-shadow: 0 4px 12px rgba(15,76,129,0.3);
    }
    .btn-outline {
      background: transparent;
      border: 2px solid var(--primary);
      color: var(--primary);
      padding: 12px 30px;
      border-radius: var(--radius-btn);
    }
    .btn-outline:hover {
      background: var(--primary);
      color: #fff;
      transform: translateY(-2px);
    }
    /* Hero */
    .hero {
      padding-top: 120px;
      display: flex;
      align-items: center;
      gap: 40px;
    }
    .hero-content {
      flex: 1;
    }
    .hero-content h1 {
      margin-bottom: 16px;
    }
    .hero-content p {
      font-size: 18px;
      color: var(--text-muted);
      margin-bottom: 32px;
      max-width: 500px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .hero-image {
      flex: 0.9;
      position: relative;
    }
    .hero-image img {
      border-radius: 16px;
      box-shadow: var(--shadow-card);
      width: 100%;
    }
    /* 卡片 */
    .card-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--bg-white);
      padding: 24px;
      border-radius: var(--radius);
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .card i {
      font-size: 40px;
      color: var(--primary);
      margin-bottom: 16px;
    }
    /* 功能交错 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .feature-row.reverse {
      flex-direction: row-reverse;
    }
    .feature-text {
      flex: 1;
    }
    .feature-text h2 {
      text-align: left;
    }
    .feature-list {
      list-style: none;
      margin-top: 20px;
    }
    .feature-list li {
      display: flex;
      align-items: center;
      gap: 12px;
      margin-bottom: 12px;
      color: var(--text-body);
    }
    .feature-list i {
      color: var(--accent);
      font-size: 18px;
    }
    .feature-image {
      flex: 1;
    }
    .feature-image img {
      border-radius: 16px;
      box-shadow: var(--shadow-card);
    }
    /* 场景卡片 */
    .scene-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .scene-card {
      background: var(--bg-white);
      border-radius: var(--radius);
      overflow: hidden;
      box-shadow: var(--shadow-card);
      transition: var(--transition);
    }
    .scene-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .scene-card img {
      height: 180px;
      object-fit: cover;
      width: 100%;
      transition: transform 0.3s;
    }
    .scene-card:hover img {
      transform: scale(1.03);
    }
    .scene-info {
      padding: 20px;
    }
    /* 案例滑动 */
    .case-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 10px;
      scroll-snap-type: x mandatory;
      -webkit-overflow-scrolling: touch;
    }
    .case-card {
      flex: 0 0 calc(25% - 18px);
      min-width: 220px;
      background: var(--bg-white);
      padding: 24px;
      border-radius: var(--radius);
      box-shadow: var(--shadow-card);
      scroll-snap-align: start;
    }
    .case-number {
      font-family: var(--font-number);
      font-size: 36px;
      font-weight: 700;
      color: var(--accent);
      margin-bottom: 8px;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 16px 0;
      cursor: pointer;
    }
    .faq-question {
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      color: var(--text-heading);
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease, background 0.2s;
      color: var(--text-body);
      line-height: 1.7;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      margin-top: 12px;
    }
    .faq-item.active {
      background: var(--bg-light);
      padding-left: 12px;
      border-radius: 8px;
    }
    /* CTA */
    .cta-section {
      background: linear-gradient(135deg, #e9f2fa 0%, #d4e3f5 100%);
      text-align: center;
      padding: 80px 24px;
    }
    .cta-section h2 {
      margin-bottom: 12px;
    }
    .footer {
      background: var(--bg-white);
      padding: 60px 0 30px;
      border-top: 1px solid var(--border);
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 30px;
    }
    .footer-links a {
      display: block;
      margin-bottom: 8px;
      color: var(--text-muted);
    }
    .footer-links a:hover {
      color: var(--primary);
      text-decoration: underline;
    }
    .copyright {
      text-align: center;
      margin-top: 40px;
      font-size: 13px;
      color: #A0AEC0;
    }
    @media (max-width: 1024px) {
      .card-grid { grid-template-columns: repeat(2,1fr); }
      .case-card { flex: 0 0 calc(50% - 12px); }
    }
    @media (max-width: 768px) {
      h1 { font-size: 32px; }
      h2 { font-size: 24px; }
      .nav-links { display: none; }
      .hamburger { display: flex; }
      .hero { flex-direction: column; padding-top: 100px; }
      .feature-row, .feature-row.reverse { flex-direction: column; }
      .scene-grid { grid-template-columns: 1fr; }
      .card-grid { grid-template-columns: 1fr; }
      .case-card { flex: 0 0 80%; }
      .footer-grid { grid-template-columns: 1fr; }
      section { padding: 60px 0; }
      .mobile-menu {
        display: none;
        position: fixed;
        top: 64px;
        left: 0;
        width: 100%;
        background: var(--bg-page);
        padding: 30px;
        flex-direction: column;
        gap: 24px;
        z-index: 99;
      }
      .mobile-menu.open { display: flex; }
    }