html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: black;
}

#game-container {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

canvas {
  display: block;
  margin: auto;
  background: black;
}