html, body {
  margin: 0;
  padding: 0;
  height: 100%;
  overflow: hidden;
  background: #7fb069;
}
#c {
  display: block;
  width: 100%;
  height: 100%;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  -webkit-touch-callout: none;
  cursor: default;
}