/* roulang page: index */
:root {
      --bg-dark: #0a0f1d;
      --card-bg: rgba(15, 23, 42, 0.72);
      --card-border: rgba(59, 130, 246, 0.2);
      --accent-glow: 0 0 24px rgba(59, 130, 246, 0.35);
      --cyan-glow: 0 0 20px rgba(6, 182, 212, 0.3);
    }
    body {
      background-color: #0a0f1d;
      color: #f1f5f9;
      font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
      overflow-x: hidden;
    }
    .glass-card {
      background: var(--card-bg);
      backdrop-filter: blur(14px);
      -webkit-backdrop-filter: blur(14px);
      border: 1px solid var(--card-border);
      transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .glass-card:hover {
      border-color: rgba(59, 130, 246, 0.55);
      box-shadow: var(--accent-glow);
      transform: translateY(-2px);
    }
    .glow-btn-primary {
      background: linear-gradient(135deg, #2563eb 0%, #06b6d4 100%);
      box-shadow: 0 0 20px rgba(37, 99, 235, 0.45);
      transition: all 0.3s ease;
    }
    .glow-btn-primary:hover {
      box-shadow: 0 0 28px rgba(6, 182, 212, 0.6);
      transform: translateY(-1px);
    }
    .glow-btn-secondary {
      background: rgba(30, 41, 59, 0.85);
      border: 1px solid rgba(59, 130, 246, 0.4);
      transition: all 0.3s ease;
    }
    .glow-btn-secondary:hover {
      background: rgba(59, 130, 246, 0.15);
      border-color: #3b82f6;
    }
    .tech-grid-pattern {
      background-size: 40px 40px;
      background-image: 
        linear-gradient(to right, rgba(255, 255, 255, 0.03) 1px, transparent 1px),
        linear-gradient(to bottom, rgba(255, 255, 255, 0.03) 1px, transparent 1px);
    }
    .accordion-content {
      max-height: 0;
      overflow: hidden;
      transition: max-height 0.35s ease-out, opacity 0.3s ease;
      opacity: 0;
    }
    .accordion-content.open {
      max-height: 300px;
      opacity: 1;
    }