:root {
  --bg-deep: #05070a;
  --glow-moss: rgba(14, 52, 32, 0.4);
  --glow-geode: rgba(95, 58, 194, 0.35);
  --glow-frost: rgba(192, 212, 228, 0.65);
}

*, *::before, *::after {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--bg-deep);
  cursor: none;
  -webkit-touch-callout: none;
  -webkit-user-select: none;
  user-select: none;
}

canvas#gl {
  display: block;
  width: 100%;
  height: 100%;
  position: fixed;
  top: 0;
  left: 0;
}

#start-overlay {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  background: radial-gradient(ellipse at center, rgba(8,16,14,0.85) 0%, rgba(5,7,10,0.97) 100%);
  transition: opacity 1.5s ease-in-out;
}

#start-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.overlay-content {
  text-align: center;
  font-family: system-ui, -apple-system, sans-serif;
}

.overlay-content h1 {
  font-size: 28px;
  font-weight: 200;
  color: rgba(180, 200, 218, 0.9);
  letter-spacing: 0.35em;
  text-transform: uppercase;
  margin-bottom: 20px;
  animation: breathe 4s ease-in-out infinite;
}

.overlay-content p {
  font-size: 13px;
  color: rgba(160, 180, 195, 0.5);
  letter-spacing: 0.15em;
  margin-bottom: 36px;
}

#start-btn {
  background: none;
  border: 1px solid rgba(140, 170, 190, 0.2);
  color: rgba(180, 200, 218, 0.7);
  font-family: inherit;
  font-size: 12px;
  letter-spacing: 0.25em;
  text-transform: uppercase;
  padding: 12px 36px;
  cursor: pointer;
  border-radius: 2px;
  transition: all 0.4s ease;
}

#start-btn:hover {
  border-color: rgba(140, 170, 190, 0.45);
  color: rgba(200, 218, 230, 0.95);
  background: rgba(140, 170, 190, 0.06);
}

@keyframes breathe {
  0%, 100% { opacity: 0.7; }
  50% { opacity: 1; }
}

@media (max-width: 600px) {
  .overlay-content h1 { font-size: 22px; }
  .overlay-content p { font-size: 11px; }
  #start-btn { font-size: 10px; padding: 10px 28px; }
}