html, body {
  margin: 0;
  padding: 0;
  background: #000000;
  width: 600px;
  height: 600px;
  overflow: hidden;
}

#app {
  width: 600px;
  height: 600px;
  position: relative;
}

#device-canvas {
  display: block;
  width: 600px;
  height: 600px;
  background: #000000;
}