/* roulang page: index */
* {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    :root {
      --primary: #0F0F1A;
      --accent-red: #FF3C3C;
      --accent-cyan: #00F0FF;
      --bg-light: #FAFAFC;
      --bg-subtle: #F0F0F5;
      --text-primary: #0F0F1A;
      --text-secondary: #4A4A5A;
      --text-muted: #8A8A9A;
      --white: #FFFFFF;
      --border-light: #E5E5EC;
      --border-dark: rgba(255,255,255,0.08);
      --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 4px 12px rgba(0,0,0,0.02);
      --shadow-hover: 0 8px 30px rgba(0,0,0,0.06);
      --radius-card: 12px;
      --radius-btn: 8px;
      --radius-tag: 4px;
      --transition: 0.2s ease;
      --container-max: 1280px;
    }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      background-color: var(--bg-light);
      color: var(--text-primary);
      line-height: 1.7;
      font-size: 16px;
      -webkit-font-smoothing: antialiased;
    }
    img {
      max-width: 100%;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
    }
    button, .btn {
      cursor: pointer;
      font-family: inherit;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
    }
    /* 导航 */
    #header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      z-index: 1000;
      background: rgba(250,250,252,0.92);
      backdrop-filter: blur(12px);
      border-bottom: 1px solid transparent;
      transition: background 0.3s, border-color 0.3s;
    }
    #header.scrolled {
      border-bottom: 1px solid var(--border-light);
    }
    .nav-container {
      display: flex;
      align-items: center;
      justify-content: space-between;
      height: 72px;
    }
    .logo {
      font-weight: 700;
      font-size: 22px;
      letter-spacing: -0.01em;
      color: var(--primary);
      display: flex;
      align-items: center;
      gap: 6px;
    }
    .logo-dot {
      width: 6px;
      height: 6px;
      background: var(--accent-cyan);
      border-radius: 50%;
      display: inline-block;
    }
    .nav-links {
      display: flex;
      gap: 32px;
      align-items: center;
    }
    .nav-link {
      font-size: 14px;
      font-weight: 500;
      color: var(--text-secondary);
      position: relative;
      transition: color 0.2s;
    }
    .nav-link::after {
      content: '';
      position: absolute;
      bottom: -4px;
      left: 50%;
      width: 0;
      height: 2px;
      background: var(--accent-red);
      transition: width 0.2s ease, left 0.2s ease;
    }
    .nav-link:hover {
      color: var(--accent-red);
    }
    .nav-link:hover::after {
      width: 100%;
      left: 0;
    }
    .header-cta {
      background: var(--accent-red);
      color: white;
      padding: 10px 24px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      font-size: 14px;
      transition: background 0.2s, transform 0.2s;
    }
    .header-cta:hover {
      background: #E02A2A;
      transform: scale(1.03);
    }
    .hamburger {
      display: none;
      background: none;
      border: none;
      font-size: 28px;
      color: var(--primary);
    }
    /* 移动端底部导航 */
    .mobile-bottom-nav {
      display: none;
      position: fixed;
      bottom: 0;
      left: 0;
      width: 100%;
      background: white;
      border-top: 1px solid var(--border-light);
      z-index: 1001;
      justify-content: space-around;
      padding: 12px 0 18px;
    }
    .mobile-nav-item {
      display: flex;
      flex-direction: column;
      align-items: center;
      font-size: 12px;
      color: var(--text-muted);
      transition: color 0.2s;
    }
    .mobile-nav-item.active {
      color: var(--accent-cyan);
    }
    .mobile-nav-icon {
      font-size: 20px;
      margin-bottom: 2px;
    }
    /* 板块通用 */
    section {
      padding: 120px 0;
    }
    .section-title {
      font-weight: 600;
      font-size: 40px;
      line-height: 1.2;
      margin-bottom: 16px;
      color: var(--primary);
    }
    .section-sub {
      font-size: 12px;
      letter-spacing: 0.15em;
      color: var(--accent-red);
      font-weight: 600;
      margin-bottom: 8px;
    }
    /* Hero */
    #hero {
      padding-top: 160px;
      padding-bottom: 120px;
      background: var(--bg-light);
      background-image: radial-gradient(circle at 20% 30%, rgba(0,240,255,0.03) 0%, transparent 50%);
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
    }
    .hero-title {
      font-weight: 700;
      font-size: 56px;
      line-height: 1.1;
      letter-spacing: -0.02em;
      margin-bottom: 24px;
      color: var(--primary);
    }
    .hero-desc {
      font-size: 18px;
      color: var(--text-secondary);
      max-width: 540px;
      margin-bottom: 32px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
    }
    .btn-primary {
      background: var(--accent-red);
      color: white;
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      border: none;
      font-size: 15px;
      transition: background 0.2s, transform 0.2s;
    }
    .btn-primary:hover {
      background: #E02A2A;
      transform: scale(1.03);
    }
    .btn-secondary {
      background: transparent;
      border: 1.5px solid var(--primary);
      color: var(--primary);
      font-weight: 600;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-size: 15px;
      transition: 0.2s;
    }
    .btn-secondary:hover {
      background: var(--primary);
      color: white;
    }
    .hero-visual {
      position: relative;
      height: 400px;
      background: radial-gradient(circle at 50% 50%, rgba(255,60,60,0.08) 0%, transparent 70%);
      display: flex;
      align-items: center;
      justify-content: center;
    }
    .geo-ring {
      width: 240px;
      height: 240px;
      border: 2px solid rgba(15,15,26,0.1);
      border-radius: 50%;
      position: absolute;
      animation: spin 20s linear infinite;
    }
    .geo-ring:nth-child(2) {
      width: 180px;
      height: 180px;
      animation-duration: 15s;
      border-color: rgba(255,60,60,0.15);
    }
    .geo-dot {
      width: 8px;
      height: 8px;
      background: var(--accent-cyan);
      border-radius: 50%;
      position: absolute;
      top: 20px;
      left: 50%;
    }
    @keyframes spin {
      to { transform: rotate(360deg); }
    }
    .scroll-indicator {
      text-align: center;
      margin-top: 60px;
      color: var(--accent-cyan);
      animation: pulse 2s infinite;
    }
    @keyframes pulse {
      0% { opacity: 0.4; transform: translateY(0); }
      50% { opacity: 1; transform: translateY(6px); }
      100% { opacity: 0.4; transform: translateY(0); }
    }
    /* Features */
    #features {
      background: var(--bg-subtle);
    }
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-top: 48px;
    }
    .feature-card {
      background: var(--white);
      padding: 32px;
      border-radius: var(--radius-card);
      border: 1px solid var(--border-light);
      box-shadow: var(--shadow-sm);
      transition: 0.25s;
    }
    .feature-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
      border-left: 3px solid var(--accent-red);
    }
    .feature-icon {
      font-size: 40px;
      margin-bottom: 20px;
      color: var(--accent-cyan);
    }
    /* Products */
    .products-grid {
      display: grid;
      grid-template-columns: repeat(4, 1fr);
      gap: 24px;
      margin-top: 48px;
    }
    .product-card {
      background: white;
      border-radius: var(--radius-card);
      border: 1px solid var(--border-light);
      overflow: hidden;
      transition: 0.25s;
    }
    .product-card:hover {
      box-shadow: var(--shadow-hover);
      transform: translateY(-4px);
      border-left: 3px solid var(--accent-red);
    }
    .product-img {
      height: 180px;
      background: #E5E5EC;
      position: relative;
      overflow: hidden;
    }
    .product-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      filter: grayscale(20%);
      transition: 0.3s;
    }
    .product-card:hover .product-img img {
      transform: scale(1.03);
      filter: grayscale(0%);
    }
    .product-content {
      padding: 24px;
    }
    /* Scenarios */
    .scenario-row {
      display: grid;
      grid-template-columns: 1fr 1fr;
      gap: 60px;
      align-items: center;
      margin-bottom: 100px;
    }
    .scenario-img {
      height: 320px;
      background: #E5E5EC;
      border-radius: var(--radius-card);
      overflow: hidden;
    }
    .scenario-img img {
      width: 100%;
      height: 100%;
      object-fit: cover;
      filter: grayscale(100%);
      transition: 0.4s;
    }
    .scenario-img:hover img {
      filter: grayscale(0%);
    }
    .scenario-number {
      font-weight: 700;
      font-size: 64px;
      color: var(--accent-cyan);
      opacity: 0.15;
      line-height: 1;
      margin-bottom: -20px;
    }
    /* Cases */
    #cases {
      background: var(--primary);
      color: white;
    }
    .stats-row {
      display: flex;
      justify-content: center;
      gap: 80px;
      margin-bottom: 64px;
      flex-wrap: wrap;
    }
    .stat-number {
      font-weight: 700;
      font-size: 48px;
      color: var(--accent-cyan);
      margin-bottom: 8px;
    }
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: rgba(255,255,255,0.04);
      border: 1px solid var(--border-dark);
      border-radius: var(--radius-card);
      padding: 32px;
    }
    .case-avatar {
      width: 64px;
      height: 64px;
      border-radius: 50%;
      background: #4A4A5A;
      margin-bottom: 20px;
      filter: grayscale(100%);
      transition: 0.3s;
    }
    .case-card:hover .case-avatar {
      filter: grayscale(0%);
    }
    /* Pricing */
    .pricing-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      margin-top: 48px;
    }
    .pricing-card {
      background: white;
      border: 1px solid var(--border-light);
      border-radius: var(--radius-card);
      padding: 40px;
      text-align: center;
      position: relative;
    }
    .pricing-card.featured {
      border-color: var(--accent-red);
      box-shadow: 0 8px 40px rgba(255,60,60,0.12);
      background: #FFF5F5;
    }
    .badge {
      position: absolute;
      top: 12px;
      right: 12px;
      background: var(--accent-red);
      color: white;
      padding: 4px 12px;
      border-radius: 20px;
      font-size: 12px;
    }
    .price {
      font-weight: 700;
      font-size: 48px;
      margin: 24px 0;
    }
    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 48px auto 0;
    }
    .faq-item {
      border-bottom: 1px solid var(--border-light);
      padding: 20px 0;
    }
    .faq-question {
      font-weight: 600;
      font-size: 18px;
      display: flex;
      justify-content: space-between;
      cursor: pointer;
      border-left: 3px solid var(--accent-red);
      padding-left: 16px;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.3s ease;
      padding-left: 19px;
      color: var(--text-secondary);
    }
    .faq-item.open .faq-answer {
      max-height: 200px;
      padding-top: 12px;
    }
    /* CTA */
    #cta {
      background: var(--primary);
      text-align: center;
    }
    .ghost-btn {
      border: 1.5px solid rgba(255,255,255,0.5);
      color: white;
      padding: 14px 32px;
      border-radius: var(--radius-btn);
      font-weight: 600;
      background: transparent;
    }
    /* footer */
    #footer {
      background: var(--primary);
      color: var(--text-muted);
      padding: 80px 0 40px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1fr;
      gap: 40px;
    }
    @media (max-width: 1024px) {
      .hero-grid { grid-template-columns: 1fr; }
      .features-grid { grid-template-columns: repeat(2,1fr); }
      .products-grid { grid-template-columns: repeat(2,1fr); }
      .cases-grid { grid-template-columns: 1fr; }
      .pricing-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
    }
    @media (max-width: 768px) {
      .nav-links, .header-cta { display: none; }
      .hamburger { display: block; }
      .mobile-bottom-nav { display: flex; }
      section { padding: 80px 0; }
      .hero-title { font-size: 36px; }
      .section-title { font-size: 28px; }
      .features-grid, .products-grid { grid-template-columns: 1fr; }
      .scenario-row { grid-template-columns: 1fr; }
    }