:root {
  --bg: #0b0f1a;
  --fg: #e6f0ff;
  --neon: #7c3aed;
  --neon-alt: #22d3ee;
}

html, body {
  height: 100%;
  margin: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: radial-gradient(1200px 800px at 50% 20%, #111831 0%, var(--bg) 60%);
  font-family: system-ui, sans-serif;
  color: var(--fg);
}

#gameCanvas {
  background: #0a0a12;
  border: 3px solid var(--neon);
  border-radius: 10px;
  box-shadow:
    0 0 0 .5px rgba(255,255,255,0.05) inset,
    0 0 20px var(--neon),
    0 0 40px rgba(124,58,237,0.6);
  max-width: 95vw;
  max-height: 80vh;
}

#gameCanvas:hover {
  border-color: var(--neon-alt);
  box-shadow:
    0 0 0 .5px rgba(255,255,255,0.07) inset,
    0 0 22px var(--neon-alt),
    0 0 44px rgba(34,211,238,0.6);
}