CSS

<style>

/******************************************************************/
/* Outshinery Spinner
/******************************************************************/
.outshinery-spinner-holder {
  position: relative;
  overflow: hidden;
  width: 100%;
  padding-top: 200%;
}

.outshinery-spinner-holder iframe {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  width: 100%;
  height: 100%;
}	

</style>

HTML

<div class="outshinery-spinner-holder">
  <iframe src="https://spinner.outshinery.com/md4ofa/" frameborder="0" scrolling="no"></iframe>
</div>