Página completa Vídeo responsivo Vimeo CSS

<!-- If you use bootstrap, it's easy : 16:9 aspect ratio -->
<div class="embed-responsive embed-responsive-16by9">
  <iframe lass="embed-responsive-item" src="https://...url_your_video..." frameborder="0" allow="autoplay; fullscreen" allowfullscreen></iframe>
</div>
Ivan The Terrible