/* roulang page: index */
:root {
      --primary-bg: #0A0E27;
      --deep-bg: #060A1A;
      --accent-cyan: #00D4FF;
      --accent-purple: #7B2FBE;
      --accent-orange: #FF6B35;
      --text-body: #B0C4DE;
      --text-heading: #FFFFFF;
      --text-muted: #6B7B8D;
      --glass-bg: rgba(255, 255, 255, 0.05);
      --glass-border: rgba(255, 255, 255, 0.12);
      --glass-blur: blur(20px);
      --card-radius: 16px;
      --btn-radius: 12px;
      --tag-radius: 20px;
      --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.3);
      --shadow-glow: 0 0 30px rgba(0, 212, 255, 0.3);
      --container-max: 1280px;
    }
    * {
      margin: 0;
      padding: 0;
      box-sizing: border-box;
    }
    html {
      scroll-behavior: smooth;
      background-color: var(--primary-bg);
    }
    body {
      font-family: system-ui, -apple-system, "PingFang SC", "Microsoft YaHei", "Helvetica Neue", sans-serif;
      background-color: var(--primary-bg);
      color: var(--text-body);
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      min-height: 100vh;
      position: relative;
    }
    body::before {
      content: "";
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 100%;
      background-image: radial-gradient(circle at 80% 20%, rgba(0,212,255,0.04) 0%, transparent 35%),
                        radial-gradient(circle at 20% 70%, rgba(123,47,190,0.05) 0%, transparent 40%);
      pointer-events: none;
      z-index: 0;
    }
    .container {
      max-width: var(--container-max);
      margin: 0 auto;
      padding: 0 24px;
      position: relative;
      z-index: 1;
    }
    img {
      max-width: 100%;
      height: auto;
      display: block;
    }
    a {
      text-decoration: none;
      color: inherit;
      transition: color 0.2s;
    }
    button {
      font-family: inherit;
      cursor: pointer;
    }

    /* Header */
    .site-header {
      position: fixed;
      top: 0;
      left: 0;
      width: 100%;
      height: 72px;
      background: rgba(10, 14, 39, 0.85);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border-bottom: 1px solid rgba(0,212,255,0.2);
      display: flex;
      align-items: center;
      z-index: 1000;
      transition: background 0.3s;
    }
    .header-inner {
      display: flex;
      justify-content: space-between;
      align-items: center;
      width: 100%;
    }
    .logo-link {
      display: flex;
      align-items: center;
      gap: 10px;
      font-weight: 700;
      font-size: 1.5rem;
      color: var(--accent-cyan);
      letter-spacing: 1px;
    }
    .logo-icon {
      width: 36px;
      height: 36px;
      background: radial-gradient(circle at 30% 30%, var(--accent-cyan), var(--accent-purple));
      border-radius: 8px;
      display: flex;
      align-items: center;
      justify-content: center;
      color: #fff;
      font-weight: 800;
      font-size: 1.25rem;
    }
    .nav-menu {
      display: flex;
      align-items: center;
      gap: 28px;
    }
    .nav-link {
      color: var(--text-body);
      font-weight: 500;
      font-size: 0.95rem;
      position: relative;
      padding: 4px 0;
    }
    .nav-link:hover,
    .nav-link.active {
      color: var(--accent-cyan);
    }
    .nav-link::after {
      content: "";
      position: absolute;
      bottom: -4px;
      left: 0;
      width: 0;
      height: 2px;
      background: var(--accent-cyan);
      transition: width 0.25s;
      box-shadow: 0 0 8px var(--accent-cyan);
    }
    .nav-link:hover::after,
    .nav-link.active::after {
      width: 100%;
    }
    .btn-primary {
      background: linear-gradient(135deg, #00D4FF, #7B2FBE);
      color: #FFFFFF;
      border: none;
      border-radius: var(--btn-radius);
      padding: 12px 28px;
      font-weight: 600;
      box-shadow: var(--shadow-glow);
      transition: all 0.3s;
      display: inline-block;
      text-align: center;
    }
    .btn-primary:hover {
      box-shadow: 0 0 50px rgba(0,212,255,0.7);
      transform: translateY(-2px);
    }
    .hamburger {
      display: none;
      flex-direction: column;
      gap: 6px;
      background: transparent;
      border: none;
      padding: 8px;
    }
    .hamburger span {
      width: 26px;
      height: 2px;
      background: var(--accent-cyan);
      transition: 0.3s;
      display: block;
    }
    .mobile-menu {
      display: none;
    }

    /* Sections */
    section {
      padding: 100px 0;
      position: relative;
    }
    .section-title {
      font-size: clamp(2rem, 3.5vw, 2.75rem);
      font-weight: 700;
      color: var(--text-heading);
      margin-bottom: 16px;
      letter-spacing: -0.01em;
    }
    .section-subtitle {
      color: var(--text-muted);
      font-size: 1.1rem;
      margin-bottom: 48px;
      max-width: 600px;
    }

    /* Hero */
    .hero {
      min-height: 90vh;
      display: flex;
      align-items: center;
      padding-top: 100px;
    }
    .hero-grid {
      display: grid;
      grid-template-columns: 5fr 7fr;
      gap: 48px;
      align-items: center;
    }
    .hero-title {
      font-size: clamp(2.5rem, 5vw, 4rem);
      font-weight: 800;
      letter-spacing: -0.02em;
      line-height: 1.15;
      background: linear-gradient(90deg, #FFFFFF, #00D4FF);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .hero-desc {
      font-size: 1.15rem;
      color: var(--text-body);
      margin: 24px 0 32px;
      max-width: 500px;
    }
    .hero-buttons {
      display: flex;
      gap: 16px;
      flex-wrap: wrap;
      margin-bottom: 40px;
    }
    .btn-outline {
      background: transparent;
      border: 1.5px solid rgba(0,212,255,0.5);
      color: var(--accent-cyan);
      border-radius: var(--btn-radius);
      padding: 14px 32px;
      font-weight: 600;
      transition: 0.3s;
    }
    .btn-outline:hover {
      background: rgba(0,212,255,0.1);
      border-color: var(--accent-cyan);
    }
    .hero-stats {
      display: flex;
      gap: 32px;
      flex-wrap: wrap;
    }
    .stat-number {
      font-size: 2.5rem;
      font-weight: 800;
      color: var(--accent-orange);
      line-height: 1.2;
    }
    .stat-label {
      color: var(--text-muted);
      font-size: 0.9rem;
    }
    .hero-image {
      background: url('/assets/images/backpic/back-1.webp') center/cover no-repeat;
      border-radius: 24px;
      height: 500px;
      width: 100%;
      box-shadow: 0 0 0 1px rgba(0,212,255,0.25), 0 25px 50px -12px rgba(0,0,0,0.5);
      position: relative;
      overflow: hidden;
    }
    .hero-image::after {
      content: "";
      position: absolute;
      inset: 0;
      background: rgba(10,14,39,0.25);
      backdrop-filter: blur(2px);
    }

    /* Features grid */
    .features-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .feature-card {
      background: var(--glass-bg);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border: 1px solid var(--glass-border);
      border-radius: var(--card-radius);
      padding: 32px 28px;
      box-shadow: var(--shadow-card);
      transition: all 0.3s ease;
    }
    .feature-card:hover {
      border-color: rgba(0,212,255,0.5);
      box-shadow: 0 8px 40px rgba(0,212,255,0.2);
      transform: translateY(-4px);
    }
    .feature-icon {
      font-size: 2.2rem;
      color: var(--accent-cyan);
      margin-bottom: 16px;
    }
    .feature-card h3 {
      color: var(--text-heading);
      font-size: 1.25rem;
      font-weight: 600;
    }

    /* Services masonry */
    .services-masonry {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
      grid-auto-rows: auto;
    }
    .service-card {
      background: var(--glass-bg);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border: 1px solid var(--glass-border);
      border-radius: var(--card-radius);
      overflow: hidden;
      transition: 0.3s;
    }
    .service-card.large {
      grid-row: span 2;
    }
    .service-img {
      height: 200px;
      background-size: cover;
      background-position: center;
      position: relative;
    }
    .service-img::after {
      content: "";
      position: absolute;
      bottom: 0;
      left: 0;
      right: 0;
      height: 60%;
      background: linear-gradient(to top, rgba(10,14,39,0.9), transparent);
    }
    .service-content {
      padding: 24px;
    }
    .service-text-card {
      padding: 36px 24px;
      text-align: center;
    }

    /* Cases */
    .cases-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 24px;
    }
    .case-card {
      background: var(--glass-bg);
      backdrop-filter: var(--glass-blur);
      -webkit-backdrop-filter: var(--glass-blur);
      border: 1px solid var(--glass-border);
      border-radius: var(--card-radius);
      overflow: hidden;
      transition: all 0.3s;
    }
    .case-card:hover {
      border-color: rgba(0,212,255,0.5);
      box-shadow: 0 12px 40px rgba(0,212,255,0.25);
      transform: translateY(-8px);
    }
    .case-img {
      height: 200px;
      background-size: cover;
      background-position: center;
      transition: transform 0.4s;
    }
    .case-card:hover .case-img {
      transform: scale(1.05);
    }
    .case-info {
      padding: 20px;
    }
    .case-tag {
      display: inline-block;
      background: rgba(0,212,255,0.15);
      color: var(--accent-cyan);
      font-size: 0.8rem;
      padding: 4px 12px;
      border-radius: var(--tag-radius);
      margin-bottom: 8px;
    }

    /* Compare table */
    .table-wrapper {
      overflow-x: auto;
      border-radius: var(--card-radius);
      border: 1px solid var(--glass-border);
    }
    .compare-table {
      width: 100%;
      border-collapse: collapse;
      min-width: 700px;
    }
    .compare-table th {
      background: rgba(0,212,255,0.08);
      color: #fff;
      padding: 18px 16px;
      font-weight: 600;
      text-align: center;
    }
    .compare-table td {
      background: var(--glass-bg);
      padding: 16px;
      text-align: center;
      border-bottom: 1px solid rgba(255,255,255,0.05);
    }
    .highlight-col {
      border-left: 2px solid var(--accent-purple);
      border-right: 2px solid var(--accent-purple);
      box-shadow: 0 0 25px rgba(123,47,190,0.3);
    }
    .badge-hot {
      background: var(--accent-orange);
      color: #fff;
      font-size: 0.7rem;
      padding: 4px 10px;
      border-radius: var(--tag-radius);
      margin-bottom: 6px;
      display: inline-block;
    }

    /* FAQ */
    .faq-list {
      max-width: 800px;
      margin: 0 auto;
    }
    .faq-item {
      border-bottom: 1px solid rgba(255,255,255,0.06);
      margin-bottom: 4px;
    }
    .faq-question {
      background: rgba(255,255,255,0.03);
      padding: 20px 24px;
      display: flex;
      justify-content: space-between;
      align-items: center;
      font-weight: 600;
      color: #fff;
      cursor: pointer;
      transition: 0.2s;
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease, padding 0.25s;
      color: var(--text-body);
      padding: 0 24px 0 32px;
      border-left: 3px solid transparent;
    }
    .faq-item.open .faq-answer {
      max-height: 220px;
      padding: 20px 24px 20px 32px;
      border-left-color: var(--accent-cyan);
    }
    .faq-arrow {
      color: var(--accent-cyan);
      transition: transform 0.3s;
    }
    .faq-item.open .faq-arrow {
      transform: rotate(180deg);
    }

    /* CTA Banner */
    .cta-banner {
      background: radial-gradient(circle at center, rgba(123,47,190,0.2), var(--primary-bg));
      text-align: center;
      padding: 80px 24px;
    }
    .cta-btn-large {
      padding: 18px 48px;
      font-size: 1.15rem;
    }

    /* Footer */
    .site-footer {
      background: var(--deep-bg);
      border-top: 1px solid rgba(0,212,255,0.15);
      padding: 60px 0 30px;
    }
    .footer-grid {
      display: grid;
      grid-template-columns: 2fr 1fr 1fr 1.5fr;
      gap: 32px;
    }
    .footer-col h4 {
      color: #fff;
      margin-bottom: 16px;
    }
    .footer-col a {
      display: block;
      color: var(--text-muted);
      margin: 6px 0;
    }
    .footer-col a:hover {
      color: var(--accent-cyan);
    }
    .copyright {
      margin-top: 40px;
      color: var(--text-muted);
      font-size: 0.85rem;
    }

    @media (max-width: 1023px) {
      .hero-grid { grid-template-columns: 1fr; }
      .features-grid { grid-template-columns: repeat(2, 1fr); }
      .services-masonry { grid-template-columns: repeat(2, 1fr); }
      .cases-grid { grid-template-columns: repeat(2, 1fr); }
    }
    @media (max-width: 767px) {
      .nav-menu { display: none; }
      .hamburger { display: flex; }
      .mobile-menu {
        position: fixed;
        top: 72px;
        left: 0;
        width: 100%;
        background: rgba(10,14,39,0.98);
        backdrop-filter: blur(25px);
        flex-direction: column;
        padding: 32px 24px;
        gap: 20px;
        display: none;
        z-index: 999;
      }
      .mobile-menu.open { display: flex; }
      .features-grid, .services-masonry, .cases-grid { grid-template-columns: 1fr; }
      .footer-grid { grid-template-columns: 1fr 1fr; }
      .hero-image { height: 300px; }
    }