/* roulang page: index */
:root {
      --primary: #0A1F3F;
      --primary-light: #122b52;
      --accent: #00E5A1;
      --accent-hover: #00cc8c;
      --bg: #F8FAFC;
      --card-bg: #FFFFFF;
      --text: #1E293B;
      --text-secondary: #64748B;
      --border: #E2E8F0;
      --shadow-sm: 0 1px 3px rgba(10,31,63,0.08), 0 4px 12px rgba(10,31,63,0.04);
      --shadow-hover: 0 4px 16px rgba(10,31,63,0.12), 0 8px 24px rgba(0,229,161,0.06);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-input: 6px;
      --font-sans: "PingFang SC", "Microsoft YaHei", "Hiragino Sans GB", sans-serif;
      --font-mono: "Inter", system-ui, -apple-system, sans-serif;
      --transition: 0.2s ease;
    }
    * {
      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;
    }
    img {
      max-width: 100%;
      display: block;
      height: auto;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
      border: none;
      background: none;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 32px;
    }
    /* 导航 */
    .nav {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.92);
      backdrop-filter: blur(12px);
      height: 72px;
      z-index: 50;
      border-bottom: 1px solid rgba(0,0,0,0.03);
      box-shadow: 0 1px 6px rgba(0,0,0,0.02);
    }
    .nav-inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 100%;
    }
    .logo {
      display: flex;
      align-items: center;
      gap: 8px;
      font-weight: 700;
      font-size: 20px;
      color: var(--primary);
    }
    .logo-icon {
      width: 20px;
      height: 20px;
      background: var(--accent);
      clip-path: polygon(50% 0%, 0% 100%, 100% 100%);
      display: inline-block;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 32px;
    }
    .nav-link {
      font-weight: 500;
      font-size: 15px;
      color: var(--text);
      transition: color var(--transition), border-bottom var(--transition);
      position: relative;
      padding: 6px 0;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: 0;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent);
      transition: width var(--transition);
    }
    .nav-link:hover {
      color: var(--accent);
    }
    .nav-link:hover::after {
      width: 100%;
    }
    .btn-primary-sm {
      background: var(--accent);
      color: var(--primary);
      padding: 10px 20px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 14px;
      transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
      display: inline-flex;
      align-items: center;
      justify-content: center;
    }
    .btn-primary-sm:hover {
      background: var(--accent-hover);
      transform: translateY(-2px);
      box-shadow: 0 4px 12px rgba(0,229,161,0.3);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 5px;
      cursor: pointer;
      background: transparent;
    }
    .hamburger span {
      width: 24px;
      height: 2px;
      background: var(--primary);
      border-radius: 2px;
      transition: var(--transition);
    }
    .mobile-menu {
      display: none;
      position: fixed;
      top: 72px;
      left: 0;
      width: 100%;
      background: rgba(255,255,255,0.98);
      backdrop-filter: blur(20px);
      flex-direction: column;
      align-items: center;
      padding: 36px 0;
      gap: 28px;
      box-shadow: var(--shadow-sm);
      z-index: 45;
    }
    .mobile-menu a {
      font-size: 20px;
      font-weight: 600;
      color: var(--primary);
    }
    /* hero */
    .hero {
      background: var(--primary);
      color: white;
      padding: 140px 0 100px;
      margin-top: 72px;
      background-image: radial-gradient(circle at 70% 30%, #1e3a5f 5%, #0A1F3F 95%);
    }
    .hero-grid {
      display: flex;
      align-items: center;
      gap: 48px;
    }
    .hero-content {
      flex: 1.3;
    }
    .hero h1 {
      font-size: 48px;
      font-weight: 700;
      letter-spacing: -0.5px;
      line-height: 1.2;
      color: white;
      margin-bottom: 16px;
    }
    .hero-sub {
      font-size: 18px;
      color: #cbd5e1;
      margin-bottom: 32px;
      max-width: 480px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent);
      color: var(--primary);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      box-shadow: none;
      transition: background var(--transition), transform var(--transition), box-shadow var(--transition);
    }
    .btn-primary:hover {
      background: var(--accent-hover);
      transform: translateY(-2px);
      box-shadow: 0 10px 20px rgba(0,229,161,0.25);
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid var(--accent);
      color: var(--accent);
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: background var(--transition), color var(--transition);
    }
    .btn-outline:hover {
      background: var(--accent);
      color: #0A1F3F;
    }
    .hero-image {
      flex: 1;
      background: rgba(255,255,255,0.05);
      border-radius: 16px;
      overflow: hidden;
    }
    .hero-image img {
      width: 100%;
      height: auto;
      object-fit: cover;
    }
    .stats-bar {
      display: flex;
      justify-content: space-between;
      margin-top: 48px;
      gap: 24px;
      flex-wrap: wrap;
    }
    .stat-item {
      flex: 1;
      min-width: 140px;
    }
    .stat-number {
      font-family: var(--font-mono);
      font-size: 32px;
      font-weight: 700;
      color: var(--accent);
    }
    .stat-label {
      color: #9ca3af;
      font-size: 14px;
    }
    /* sections */
    section {
      padding: 120px 0;
    }
    .section-title {
      font-size: 36px;
      font-weight: 600;
      margin-bottom: 48px;
      color: var(--primary);
    }
    /* 优势1+2 */
    .advantage-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .advantage-main {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 32px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
      display: flex;
      flex-direction: column;
    }
    .advantage-main:hover {
      box-shadow: var(--shadow-hover);
      border-left: 3px solid var(--accent);
    }
    .advantage-icon {
      font-size: 36px;
      color: var(--accent);
      margin-bottom: 16px;
    }
    .advantage-sub {
      display: flex;
      flex-direction: column;
      gap: 24px;
    }
    .advantage-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      padding: 24px;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .advantage-card:hover {
      box-shadow: var(--shadow-hover);
      border-left: 3px solid var(--accent);
    }
    /* 图文交替 */
    .feature-row {
      display: flex;
      align-items: center;
      gap: 60px;
      margin-bottom: 80px;
    }
    .feature-row.reverse {
      flex-direction: row-reverse;
    }
    .feature-text {
      flex: 1;
    }
    .feature-img {
      flex: 1;
      background: #f1f5f9;
      border-radius: 12px;
      overflow: hidden;
    }
    .feature-img img {
      width: 100%;
      height: auto;
    }
    .feature-list {
      list-style: none;
      margin: 16px 0;
    }
    .feature-list li::before {
      content: "●";
      color: var(--accent);
      margin-right: 8px;
    }
    /* 场景2列 */
    .scene-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 24px;
    }
    .scene-card {
      background: var(--card-bg);
      border-radius: var(--radius-card);
      overflow: hidden;
      box-shadow: var(--shadow-sm);
      transition: var(--transition);
    }
    .scene-card:hover {
      transform: translateY(-4px);
      box-shadow: var(--shadow-hover);
    }
    .scene-img {
      width: 100%;
      aspect-ratio: 16/9;
      object-fit: cover;
    }
    .scene-info {
      padding: 20px;
    }
    .tag {
      background: #e6f7f0;
      color: #0f766e;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
      font-weight: 600;
    }
    /* 案例横向滚动 */
    .case-scroll {
      display: flex;
      gap: 24px;
      overflow-x: auto;
      padding-bottom: 16px;
      scroll-snap-type: x mandatory;
    }
    .case-card {
      min-width: 280px;
      flex: 0 0 auto;
      background: #F1F5F9;
      border-radius: var(--radius-card);
      padding: 24px;
      scroll-snap-align: start;
    }
    .case-number {
      font-size: 28px;
      font-weight: 700;
      color: var(--accent);
      font-family: var(--font-mono);
    }
    /* FAQ */
    .faq-item {
      border-bottom: 1px solid var(--border);
      padding: 20px 0;
    }
    .faq-question {
      font-size: 18px;
      font-weight: 600;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      border-left: 3px solid var(--accent);
      padding-left: 16px;
      background: none;
      width: 100%;
      text-align: left;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      color: var(--text-secondary);
      padding-left: 19px;
      margin-top: 10px;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
    }
    /* CTA banner */
    .cta-banner {
      background: var(--primary);
      text-align: center;
      padding: 80px 0;
      color: white;
    }
    .cta-banner h2 {
      color: white;
      font-size: 36px;
    }
    .btn-lg {
      background: var(--accent);
      color: #0A1F3F;
      padding: 16px 48px;
      font-size: 18px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      transition: var(--transition);
    }
    .btn-lg:hover {
      background: #00cc8c;
      transform: translateY(-2px);
    }
    /* footer */
    .footer {
      background: #0A1F3F;
      color: #94A3B8;
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 32px;
      margin-bottom: 30px;
    }
    .footer a {
      color: #cbd5e1;
    }
    .footer-copy {
      border-top: 1px solid #2d3a4f;
      padding-top: 20px;
      text-align: center;
      font-size: 14px;
    }
    @media (max-width: 1024px) {
      .hero-grid { flex-direction: column; }
      .advantage-grid { grid-template-columns: 1fr; }
      .container { padding: 0 24px; }
    }
    @media (max-width: 768px) {
      .nav-menu { display: none; }
      .hamburger { display: flex; }
      .feature-row, .feature-row.reverse { flex-direction: column; }
      .scene-grid { grid-template-columns: 1fr; }
      .stats-bar { flex-direction: column; }
      .footer-grid { grid-template-columns: 1fr; }
      h1 { font-size: 32px; }
      .hero-sub { font-size: 16px; }
    }