<div class="video-container">
  <iframe allowfullscreen="" frameborder="0" height="315" src="https://www.youtube.com/embed/N3iagEDj2_4" width="560"></iframe>
</div>
.video-container {
  position: relative;
  padding-bottom: 56.25%;
  padding-top: 30px; 
  height: 0; 
  overflow: hidden;
}

.video-container iframe,
.video-container object,
.video-container embed {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

External CSS

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External JavaScript

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