zurb-foundation-5/doc/includes/kitchen/examples_kitchen_flex_video.html

Foundation 5 for npm (no code modification from original repo)

<div class="flex-video">
  <iframe width="420" height="315" src="http://www.youtube.com/embed/0_EW8aNgKlA" frameborder="0" allowfullscreen></iframe>
</div>