html, body {
  width: 100%;
  height: 100%;
  margin: 0;
  padding: 0;
  overflow: hidden;
  background: #000;
  color: #ccc;
  font-family: Arial, Verdana, sans-serif;
  -webkit-tap-highlight-color: transparent;
  -webkit-touch-callout: none;
  -webkit-text-size-adjust: none;
  -webkit-user-select: none;
  user-select: none;
}
#content {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: #000;
}
#content canvas {
  display: block;
  margin: 0 auto;
}
#loader {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
  background: #000;
  color: #fff;
  font: 18px/1.4 Arial, sans-serif;
  pointer-events: none;
}

html,body,#content{width:100%;height:100%;}
#content{position:fixed;inset:0;overflow:hidden;}
#content canvas{display:block;margin:0 auto;}