/* roulang page: index */
:root {
      --primary: #4E6EF2;
      --primary-hover: #3B5BDB;
      --primary-soft: rgba(78,110,242,0.06);
      --primary-glow: rgba(78,110,242,0.18);
      --success: #00B578;
      --warning: #FF9F0A;
      --danger: #FA5151;
      --text-dark: #1F2329;
      --text-secondary: #86909C;
      --bg-page: #F5F6FA;
      --bg-card: #FFFFFF;
      --bg-scene: #F0F2F8;
      --border-light: #E5E8EF;
      --shadow-card: 0 2px 12px rgba(0,0,0,0.04), 0 0 1px rgba(0,0,0,0.02);
      --shadow-card-hover: 0 8px 24px rgba(0,0,0,0.08);
      --shadow-btn: 0 4px 10px rgba(78,110,242,0.3);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-capsule: 24px;
      --radius-input: 8px;
      --transition: 200ms ease;
      --font-stack: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      --container-max: 1200px;
      --nav-height: 64px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    body {
      font-family: var(--font-stack);
      background: var(--bg-page);
      color: var(--text-dark);
      line-height: 1.5;
      -webkit-font-smoothing: antialiased;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    button, input, textarea {
      font-family: inherit;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航栏 */
    .header {
      position: sticky;
      top: 0;
      z-index: 100;
      background: var(--bg-card);
      height: var(--nav-height);
      box-shadow: 0 1px 4px rgba(0,0,0,0.04);
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .nav {
      display: flex;
      align-items: center;
      justify-content: space-between;
      width: 100%;
      max-width: var(--container-max);
      padding: 0 24px;
    }
    .logo {
      font-size: 20px;
      font-weight: 700;
      color: var(--text-dark);
      letter-spacing: 1px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .logo i {
      color: var(--primary);
      font-size: 24px;
    }
    .nav-links {
      display: flex;
      align-items: center;
      gap: 32px;
      list-style: none;
    }
    .nav-links a {
      font-size: 16px;
      font-weight: 500;
      color: var(--text-dark);
      transition: color var(--transition);
      position: relative;
      padding: 8px 0;
    }
    .nav-links a:hover,
    .nav-links a.active {
      color: var(--primary);
    }
    .nav-links a.active::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 100%;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
    }
    .nav-cta {
      background: var(--primary);
      color: white;
      padding: 8px 24px;
      border-radius: var(--radius-capsule);
      font-weight: 500;
      font-size: 15px;
      transition: background var(--transition), box-shadow var(--transition);
      white-space: nowrap;
    }
    .nav-cta:hover {
      background: var(--primary-hover);
      box-shadow: var(--shadow-btn);
    }
    .menu-toggle {
      display: none;
      background: none;
      border: none;
      font-size: 26px;
      color: var(--text-dark);
      cursor: pointer;
    }
    /* Hero */
    .hero {
      background: var(--bg-card);
      padding: 56px 0 64px;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .hero::before {
      content: '';
      position: absolute;
      inset: 0;
      background: rgba(255,255,255,0.85);
      z-index: 0;
    }
    .hero .container {
      position: relative;
      z-index: 1;
      display: flex;
      align-items: center;
      gap: 48px;
      flex-wrap: wrap;
    }
    .hero-text {
      flex: 1 1 500px;
    }
    .hero-text h1 {
      font-size: 44px;
      font-weight: 700;
      line-height: 1.2;
      color: var(--text-dark);
      margin-bottom: 16px;
    }
    .hero-text .sub {
      font-size: 18px;
      color: var(--text-secondary);
      max-width: 480px;
      margin-bottom: 28px;
    }
    .hero-stats {
      display: flex;
      gap: 32px;
      margin-bottom: 32px;
      flex-wrap: wrap;
    }
    .stat-item {
      text-align: left;
    }
    .stat-number {
      font-size: 28px;
      font-weight: 700;
      color: var(--primary);
    }
    .stat-label {
      font-size: 13px;
      color: var(--text-secondary);
    }
    .hero-actions {
      display: flex;
      align-items: center;
      gap: 24px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      padding: 12px 32px;
      border-radius: var(--radius-btn);
      font-weight: 500;
      font-size: 16px;
      border: none;
      cursor: pointer;
      transition: background var(--transition), box-shadow var(--transition);
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      background: var(--primary-hover);
      box-shadow: var(--shadow-btn);
    }
    .btn-outline {
      background: transparent;
      color: var(--primary);
      border: 1px solid var(--primary);
      padding: 11px 31px;
      border-radius: var(--radius-btn);
      font-weight: 500;
      font-size: 16px;
      transition: background var(--transition);
      display: inline-block;
    }
    .btn-outline:hover {
      background: var(--primary-soft);
    }
    .link-arrow {
      color: var(--primary);
      font-weight: 500;
      display: inline-flex;
      align-items: center;
      gap: 6px;
      font-size: 15px;
      transition: gap var(--transition);
    }
    .link-arrow:hover {
      gap: 10px;
    }
    .hero-image {
      flex: 1 1 400px;
      background: #E5E8EF;
      border-radius: var(--radius-card);
      overflow: hidden;
      min-height: 280px;
      display: flex;
      align-items: center;
      justify-content: center;
      box-shadow: var(--shadow-card);
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    /* 板块通用 */
    .section {
      padding: 80px 0;
    }
    .section-title {
      text-align: center;
      margin-bottom: 48px;
    }
    .section-title h2 {
      font-size: 30px;
      font-weight: 600;
      color: var(--text-dark);
      display: inline-block;
      position: relative;
      padding-bottom: 12px;
    }
    .section-title h2::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 50%;
      transform: translateX(-50%);
      width: 48px;
      height: 3px;
      background: var(--primary);
      border-radius: 4px;
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .grid-2 {
      display: grid;
      grid-template-columns: repeat(2, 1fr);
      gap: 24px;
    }
    .card {
      background: var(--bg-card);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-card);
      transition: box-shadow var(--transition), transform var(--transition);
    }
    .card:hover {
      box-shadow: var(--shadow-card-hover);
      transform: translateY(-4px);
    }
    .icon-box {
      width: 56px;
      height: 56px;
      background: rgba(78,110,242,0.08);
      border-radius: var(--radius-card);
      display: flex;
      align-items: center;
      justify-content: center;
      margin-bottom: 20px;
      color: var(--primary);
      font-size: 26px;
    }
    .card h3 {
      font-size: 20px;
      font-weight: 600;
      margin-bottom: 10px;
    }
    .card p {
      font-size: 15px;
      color: var(--text-secondary);
      line-height: 1.6;
    }
    /* 产品区左右交替 */
    .service-row {
      display: flex;
      align-items: center;
      gap: 48px;
      margin-bottom: 64px;
      flex-wrap: wrap;
    }
    .service-row.reverse {
      flex-direction: row-reverse;
    }
    .service-img {
      flex: 1 1 400px;
      background: #E5E8EF;
      border-radius: var(--radius-card);
      overflow: hidden;
      min-height: 260px;
      box-shadow: var(--shadow-card);
    }
    .service-img img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    .service-content {
      flex: 1 1 400px;
    }
    .service-content h3 {
      font-size: 24px;
      font-weight: 600;
      margin-bottom: 16px;
    }
    .service-content ul {
      list-style: none;
      margin-bottom: 20px;
    }
    .service-content li {
      font-size: 15px;
      color: var(--text-secondary);
      margin-bottom: 8px;
      display: flex;
      align-items: center;
      gap: 8px;
    }
    .service-content li i {
      color: var(--primary);
    }
    /* 场景卡片 */
    .scene-card {
      background: var(--bg-scene);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: none;
    }
    .scene-img {
      height: 180px;
      background: #D9DDE8;
      overflow: hidden;
    }
    .scene-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
    }
    .scene-body {
      padding: 24px;
    }
    /* FAQ */
    .faq-item {
      background: var(--bg-card);
      border-bottom: 1px solid var(--border-light);
    }
    .faq-question {
      padding: 16px 24px;
      font-weight: 600;
      font-size: 16px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      cursor: pointer;
      user-select: none;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.25s ease;
      padding: 0 24px;
      font-size: 14px;
      color: var(--text-secondary);
      line-height: 1.6;
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-bottom: 16px;
    }
    .faq-icon {
      transition: transform 0.2s;
      font-size: 20px;
    }
    .faq-item.open .faq-icon {
      transform: rotate(45deg);
    }
    /* CTA */
    .cta-section {
      background: var(--primary);
      padding: 72px 0;
      text-align: center;
      color: white;
    }
    .cta-section h2 {
      font-size: 32px;
      font-weight: 600;
      margin-bottom: 12px;
    }
    .cta-sub {
      font-size: 16px;
      opacity: 0.9;
      margin-bottom: 32px;
    }
    .cta-form {
      display: flex;
      gap: 12px;
      max-width: 600px;
      margin: 0 auto 24px;
      flex-wrap: wrap;
      justify-content: center;
    }
    .cta-form input {
      flex: 1 1 180px;
      padding: 12px 16px;
      border-radius: var(--radius-input);
      border: 1px solid transparent;
      background: white;
      outline: none;
      transition: box-shadow 0.2s;
    }
    .cta-form input:focus {
      box-shadow: 0 0 0 3px rgba(255,255,255,0.4);
    }
    .btn-white {
      background: white;
      color: var(--primary);
      border: none;
      padding: 12px 28px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      cursor: pointer;
      transition: background 0.2s;
    }
    .btn-white:hover {
      background: #f0f2ff;
    }
    /* 页脚 */
    .footer {
      background: var(--bg-card);
      padding: 60px 0 24px;
      border-top: 1px solid var(--border-light);
    }
    .footer-grid {
      display: grid;
      grid-template-columns: repeat(4,1fr);
      gap: 32px;
      margin-bottom: 40px;
    }
    .footer-col h4 {
      font-weight: 600;
      margin-bottom: 16px;
    }
    .footer-col a {
      display: block;
      color: var(--text-secondary);
      font-size: 14px;
      margin-bottom: 10px;
      transition: color 0.2s;
    }
    .footer-col a:hover {
      color: var(--primary);
    }
    .copyright {
      text-align: center;
      color: var(--text-secondary);
      font-size: 13px;
      padding-top: 20px;
      border-top: 1px solid var(--border-light);
    }
    /* 响应式 */
    @media (max-width: 991px) {
      .grid-3 { grid-template-columns: repeat(2,1fr); }
      .nav-links { display: none; }
      .menu-toggle { display: block; }
    }
    @media (max-width: 767px) {
      .hero .container { flex-direction: column; }
      .hero-text h1 { font-size: 30px; }
      .grid-3, .grid-2, .footer-grid { grid-template-columns: 1fr; }
      .service-row, .service-row.reverse { flex-direction: column; }
      .cta-form { flex-direction: column; align-items: stretch; }
      .hero-stats { gap: 20px; }
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: var(--nav-height);
      left: 0;
      right: 0;
      background: white;
      flex-direction: column;
      padding: 24px;
      gap: 20px;
      box-shadow: 0 8px 20px rgba(0,0,0,0.08);
      z-index: 99;
    }
    .mobile-menu a {
      font-size: 18px;
      font-weight: 500;
    }
    .mobile-menu.open {
      display: flex;
    }