/* roulang page: index */
:root {
      --deep-space: #0B0E2D;
      --nebula-purple: #7C3AED;
      --amber-gold: #F59E0B;
      --soft-bg: #FAFBFE;
      --card-bg: #FFFFFF;
      --body-text: #1E293B;
      --muted-text: #64748B;
      --border-light: #E2E8F0;
      --shadow-sm: 0 1px 2px 0 rgba(0,0,0,0.03);
      --shadow-md: 0 4px 6px -1px rgba(0,0,0,0.05), 0 2px 4px -1px rgba(0,0,0,0.03);
      --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.08), 0 10px 10px -5px rgba(0,0,0,0.02);
      --radius-2xl: 1rem;
      --transition-smooth: all 0.3s ease;
    }
    * {
      box-sizing: border-box;
    }
    body {
      font-family: 'Inter', 'PingFang SC', 'Microsoft YaHei', system-ui, -apple-system, sans-serif;
      background-color: var(--soft-bg);
      color: var(--body-text);
      line-height: 1.6;
      margin: 0;
      padding: 0;
      -webkit-font-smoothing: antialiased;
    }
    .container-custom {
      max-width: 1280px;
      margin-left: auto;
      margin-right: auto;
      padding-left: 1.5rem;
      padding-right: 1.5rem;
    }
    @media (min-width: 1024px) {
      .container-custom {
        padding-left: 2rem;
        padding-right: 2rem;
      }
    }
    .text-gradient {
      background: linear-gradient(135deg, var(--nebula-purple) 0%, #a78bfa 80%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
      background-clip: text;
    }
    .btn-primary {
      background: linear-gradient(135deg, var(--nebula-purple) 0%, var(--deep-space) 100%);
      color: white;
      font-weight: 600;
      letter-spacing: 0.02em;
      padding: 0.75rem 2rem;
      border-radius: 0.75rem;
      box-shadow: 0 8px 20px -8px rgba(124,58,237,0.4);
      transition: var(--transition-smooth);
      display: inline-flex;
      align-items: center;
      justify-content: center;
      border: none;
      cursor: pointer;
      text-decoration: none;
    }
    .btn-primary:hover {
      transform: scale(1.05);
      box-shadow: 0 15px 25px -8px rgba(124,58,237,0.5);
    }
    .btn-outline {
      border: 2px solid var(--deep-space);
      color: var(--deep-space);
      font-weight: 600;
      padding: 0.75rem 2rem;
      border-radius: 0.75rem;
      transition: var(--transition-smooth);
      background: transparent;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      text-decoration: none;
    }
    .btn-outline:hover {
      background: var(--deep-space);
      color: white;
    }
    .card-hover {
      background: var(--card-bg);
      border-radius: var(--radius-2xl);
      box-shadow: var(--shadow-sm);
      transition: var(--transition-smooth);
      border: 1px solid var(--border-light);
      height: 100%;
    }
    .card-hover:hover {
      box-shadow: var(--shadow-xl);
      transform: translateY(-6px);
      border-bottom: 3px solid var(--nebula-purple);
    }
    .data-badge {
      background: rgba(245,158,11,0.1);
      color: #b45309;
      font-weight: 700;
      font-size: 2.5rem;
      line-height: 1.2;
      padding: 0.5rem 1rem;
      border-radius: 0.75rem;
      display: inline-block;
      letter-spacing: -0.5px;
    }
    .section-heading {
      font-size: 2.25rem;
      font-weight: 700;
      letter-spacing: -0.02em;
      margin-bottom: 0.75rem;
    }
    @media (min-width: 768px) {
      .section-heading {
        font-size: 2.8rem;
      }
    }
    .hero-bg {
      background: radial-gradient(circle at 30% 30%, rgba(124,58,237,0.25) 0%, rgba(11,14,45,0.98) 85%);
      position: relative;
      overflow: hidden;
    }
    .hero-bg::before {
      content: "";
      position: absolute;
      top:0; left:0; right:0; bottom:0;
      background-image: url('/assets/images/backpic/back-1.webp');
      background-size: cover;
      background-position: center;
      opacity: 0.25;
      mix-blend-mode: overlay;
      pointer-events: none;
    }
    .particle {
      position: absolute;
      width: 4px;
      height: 4px;
      background: white;
      border-radius: 50%;
      opacity: 0.5;
      animation: float 6s infinite ease-in-out;
    }
    @keyframes float {
      0% { transform: translateY(0px) scale(1); opacity: 0.3; }
      50% { transform: translateY(-25px) scale(1.2); opacity: 0.7; }
      100% { transform: translateY(0px) scale(1); opacity: 0.3; }
    }
    .faq-answer {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.4s ease, padding 0.3s ease;
      padding: 0 1rem;
    }
    .faq-item.active .faq-answer {
      max-height: 200px;
      padding: 1rem;
    }
    .faq-item.active .faq-icon {
      transform: rotate(45deg);
    }
    .nav-link {
      position: relative;
      font-weight: 500;
      color: var(--body-text);
      transition: color 0.2s;
    }
    .nav-link:hover {
      color: var(--nebula-purple);
    }
    @media (max-width: 767px) {
      .mobile-menu {
        display: none;
      }
      .mobile-menu.open {
        display: flex;
        flex-direction: column;
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        bottom: 0;
        background: var(--deep-space);
        padding: 2rem;
        z-index: 100;
        gap: 2rem;
      }
    }