html, body {
  margin: 0;
  padding: 0;
  height: 100vh;
  background: radial-gradient(circle, #001122 0%, #000000 100%);
  color: #fff;
  font-family: 'Courier New', monospace;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: center;
}

#gameCanvas {
  display: block;
  border: 3px solid rgb(255, 255, 255);
  box-shadow: 0 0 30px rgba(255, 255, 255, 0.5);
  background: #000;
  max-width: 95vw;
  max-height: 95vh;
}