html, body {
  margin: 0;
  height: 100%;
}
model-viewer {
  width: 100%;
  height: 100%;
}
button {
  position: absolute;
  top: 16px;
  right: 16px;
  width: 50px;
  height: 50px;
  border: 0;
  border-radius: 100px;
  background: url( "../img/bg_01.png" ) 0 0 / 100% 100%;
}