:host {
  display: block;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  height: 100%;
  padding: 3px;
  background: #222;
}
:host.preview {
  position: absolute;
  z-index: 1;
  padding: 30px;
}
iframe {
  width: 100%;
  height: 100%;
  border: 0;
}