responsive youtube video on a website

/*Add CSS*/
.container {
  position: relative;
  overflow: hidden;
  width: 100%;
  padding-top: 56.25%; /* 16:9 Aspect Ratio (divide 9 by 16 = 0.5625) */
}

/* Then style the iframe to fit in the container div with full height and width */
.responsive-iframe {
  position: absolute;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  width: 100%;
  height: 100%;
}<!--Add HTML:-->
<!--Replace "tgbNymZ7vqY"-->
<div class="container">
  <iframe class="responsive-iframe" src="https://www.youtube.com/embed/tgbNymZ7vqY"></iframe>
</div>