Mask up!

<div style="padding-top: 56.25%; overflow: hidden; position:relative; -webkit-box-flex: 1; flex-grow: 1;">
  <iframe
    style="bottom: 0; left: 0; position: absolute; right: 0; top: 0; border: 0; height: 100%; width: 100%;"
    src="https://mediahub.unl.edu/media/14433?format=iframe&autoplay=0"
    title="Video Player:  Mask up!"
    allowfullscreen
  ></iframe>
</div>