/* roulang page: index */
:root {
      --bg-deep: #0D0B1E;
      --primary: #A855F7;
      --accent: #00F0FF;
      --card-bg: rgba(30, 27, 46, 0.65);
      --border-card: rgba(168, 85, 247, 0.25);
      --text-primary: #F5F3FF;
      --text-secondary: #A5A2B8;
      --shadow-glow: 0 0 20px rgba(168,85,247,0.6);
      --shadow-accent: 0 0 24px rgba(0,240,255,0.7);
      --radius-card: 16px;
      --radius-btn: 50px;
      --radius-img: 12px;
    }
    * {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }
    body {
      background-color: var(--bg-deep);
      color: var(--text-primary);
      font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
      line-height: 1.75;
      -webkit-font-smoothing: antialiased;
      overflow-x: hidden;
    }
    .container {
      max-width: 1280px;
      margin: 0 auto;
      padding: 0 1.5rem;
    }
    h1, h2, h3, .lead {
      font-weight: 700;
    }
    h1 {
      font-size: clamp(2.5rem, 6vw, 4rem);
      font-weight: 800;
      letter-spacing: -0.02em;
      color: var(--text-primary);
      line-height: 1.2;
    }
    h2 {
      font-size: clamp(1.8rem, 4vw, 2.5rem);
      color: var(--text-primary);
      margin-bottom: 0.75rem;
      position: relative;
      display: inline-block;
    }
    h2::after {
      content: '';
      display: block;
      width: 40px;
      height: 2px;
      background: var(--accent);
      margin-top: 0.5rem;
      border-radius: 2px;
    }
    h3 {
      font-size: 1.25rem;
      font-weight: 600;
      color: var(--text-primary);
      margin-bottom: 0.5rem;
    }
    .text-secondary {
      color: var(--text-secondary);
      font-size: 1rem;
      line-height: 1.75;
    }
    .tag {
      font-size: 0.875rem;
      color: var(--accent);
      text-transform: uppercase;
      letter-spacing: 0.05em;
      font-weight: 600;
    }
    .btn {
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 0.75rem 2rem;
      border-radius: var(--radius-btn);
      font-weight: 600;
      text-decoration: none;
      transition: all 0.3s ease;
      border: 2px solid transparent;
      cursor: pointer;
      font-size: 1rem;
      gap: 0.5rem;
    }
    .btn-primary {
      background: var(--primary);
      color: white;
      border-color: var(--primary);
    }
    .btn-primary:hover {
      background: #C084FC;
      border-color: #C084FC;
      box-shadow: var(--shadow-glow);
      transform: translateY(-2px);
      color: white;
    }
    .btn-outline {
      background: transparent;
      border-color: var(--primary);
      color: var(--primary);
    }
    .btn-outline:hover {
      background: rgba(168,85,247,0.15);
      border-color: var(--accent);
      color: var(--accent);
      box-shadow: 0 0 12px rgba(0,240,255,0.4);
    }
    .btn-accent {
      background: var(--accent);
      color: var(--bg-deep);
      border-color: var(--accent);
      font-weight: 700;
    }
    .btn-accent:hover {
      box-shadow: var(--shadow-accent);
      background: #33F5FF;
      color: #0D0B1E;
    }
    .card {
      background: var(--card-bg);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border: 1px solid var(--border-card);
      border-radius: var(--radius-card);
      padding: 2rem;
      transition: all 0.3s ease;
    }
    .card:hover {
      border-color: rgba(0,240,255,0.5);
      box-shadow: 0 8px 32px rgba(168,85,247,0.2);
      transform: translateY(-4px);
    }
    .glass-img {
      border-radius: var(--radius-img);
      box-shadow: 0 0 40px rgba(168,85,247,0.4);
      width: 100%;
      height: auto;
      display: block;
    }
    header.sticky-nav {
      position: sticky;
      top: 0;
      z-index: 100;
      background: rgba(13, 11, 30, 0.85);
      backdrop-filter: blur(20px);
      border-bottom: 1px solid rgba(168,85,247,0.2);
      padding: 0.75rem 0;
    }
    .nav-logo {
      font-size: 1.8rem;
      font-weight: 800;
      color: var(--accent);
      text-decoration: none;
      letter-spacing: -0.5px;
    }
    .nav-logo span {
      color: var(--primary);
    }
    .nav-link {
      color: var(--text-secondary);
      margin: 0 0.75rem;
      font-weight: 500;
      transition: color 0.2s;
    }
    .nav-link:hover {
      color: var(--accent);
    }
    .mobile-bottom-tab {
      position: fixed;
      bottom: 0;
      left: 0;
      right: 0;
      z-index: 100;
      background: rgba(13, 11, 30, 0.95);
      backdrop-filter: blur(20px);
      border-top: 1px solid rgba(168,85,247,0.3);
      display: flex;
      justify-content: space-around;
      padding: 0.5rem 0 0.75rem;
    }
    @media (min-width: 1025px) {
      .mobile-bottom-tab {
        display: none;
      }
    }
    .tab-item {
      color: var(--text-secondary);
      font-size: 0.65rem;
      text-align: center;
      text-decoration: none;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 0.2rem;
    }
    .tab-item i {
      font-size: 1.4rem;
    }
    .tab-item.active {
      color: var(--accent);
    }
    .hero-section {
      padding: 4rem 0 6rem;
      display: flex;
      align-items: center;
      gap: 2rem;
      flex-wrap: wrap;
    }
    .hero-left {
      flex: 1 1 50%;
    }
    .hero-right {
      flex: 1 1 40%;
      animation: float 6s ease-in-out infinite;
    }
    @keyframes float {
      0%, 100% { transform: translateY(0); }
      50% { transform: translateY(-10px); }
    }
    .grid-3 {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 2rem;
    }
    .features-layout {
      display: flex;
      gap: 2.5rem;
      flex-wrap: wrap;
    }
    .features-left {
      flex: 1 1 30%;
    }
    .features-right {
      flex: 1 1 60%;
      display: flex;
      flex-direction: column;
      gap: 1.8rem;
    }
    .service-row {
      display: flex;
      gap: 1.5rem;
      align-items: flex-start;
      background: var(--card-bg);
      backdrop-filter: blur(12px);
      border: 1px solid var(--border-card);
      border-radius: var(--radius-card);
      padding: 1.5rem;
      transition: 0.3s;
    }
    .service-row:hover {
      border-color: var(--accent);
      box-shadow: 0 8px 24px rgba(168,85,247,0.2);
    }
    .cases-waterfall {
      columns: 3;
      column-gap: 1.5rem;
    }
    .case-card {
      break-inside: avoid;
      margin-bottom: 1.5rem;
      background: var(--card-bg);
      backdrop-filter: blur(12px);
      border: 1px solid var(--border-card);
      border-radius: 12px;
      overflow: hidden;
    }
    .case-card img {
      width: 100%;
      display: block;
      border-radius: 12px 12px 0 0;
    }
    .compare-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: 1.5rem;
    }
    .compare-card.featured {
      border-color: var(--accent);
      box-shadow: 0 0 30px rgba(0,240,255,0.3);
    }
    .accordion-title {
      font-size: 1.1rem;
      font-weight: 600;
      color: var(--primary);
      background: transparent;
      border: none;
      width: 100%;
      text-align: left;
      padding: 1rem 0;
    }
    .accordion-content {
      color: var(--text-secondary);
      background: rgba(30,27,46,0.5);
      padding: 0 1rem 1rem;
    }
    .cta-full {
      background: linear-gradient(135deg, #0D0B1E 0%, #1E1B2E 50%, #0D0B1E 100%);
      text-align: center;
      padding: 5rem 1.5rem;
    }
    footer {
      background: #0A0816;
      color: var(--text-secondary);
      padding: 3rem 0 1.5rem;
    }
    @media (max-width: 1024px) {
      .grid-3 { grid-template-columns: repeat(2, 1fr); }
      .cases-waterfall { columns: 2; }
      .compare-grid { grid-template-columns: 1fr; }
      .features-layout { flex-direction: column; }
    }
    @media (max-width: 640px) {
      .grid-3 { grid-template-columns: 1fr; }
      .cases-waterfall { columns: 1; }
      .hero-section { flex-direction: column; }
      .service-row { flex-direction: column; }
    }