* {
  box-sizing: border-box;
}
html, body, main {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  background: #000;
}
canvas {
  display: block;
  margin: auto;
}
#controls {
  width: 100%;
  text-align: center;
  padding: 1rem
}

button {
  background: #000;
  color: #FFF;
  border: solid 2px #FFF;
  padding: 1em;
  cursor: pointer;
}
button.active,
button:active {
  background: #FFF;
  color: #000;
  border-color: #000;
}