/* roulang page: index */
:root {
      --primary-dark: #0B0F19;
      --card-dark: #111827;
      --brand-indigo: #4F46E5;
      --brand-cyan: #06B6D4;
      --accent-emerald: #10B981;
      --text-muted: #64748B;
      --border-subtle: rgba(255, 255, 255, 0.08);
    }
    html {
      scroll-behavior: smooth;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    }
    body {
      background-color: #0B0F19;
      color: #E2E8F0;
      overflow-x: hidden;
    }
    .brand-gradient-text {
      background: linear-gradient(135deg, #818CF8 0%, #38BDF8 100%);
      -webkit-background-clip: text;
      -webkit-text-fill-color: transparent;
    }
    .brand-gradient-btn {
      background: linear-gradient(135deg, #4F46E5 0%, #06B6D4 100%);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .brand-gradient-btn:hover {
      box-shadow: 0 0 25px rgba(79, 70, 229, 0.45);
      transform: translateY(-2px);
    }
    .glass-nav {
      background: rgba(11, 15, 25, 0.85);
      backdrop-filter: blur(16px);
      -webkit-backdrop-filter: blur(16px);
      border-bottom: 1px solid rgba(255, 255, 255, 0.08);
    }
    .card-hover-effect {
      transition: transform 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
    }
    .card-hover-effect:hover {
      transform: translateY(-4px);
      border-color: rgba(79, 70, 229, 0.5);
      box-shadow: 0 15px 35px -5px rgba(0, 0, 0, 0.5);
    }
    details > summary {
      list-style: none;
    }
    details > summary::-webkit-details-marker {
      display: none;
    }