.responsive-youtube {
  overflow: hidden;
  padding-bottom: 56.25%;
  position: relative;
  height: 0px;
  border-radius: 4px;
  margin-top: -16px;
  margin-bottom: 0px;
}

.responsive-youtube iframe {
  left: 0px;
  top: 0px;
  height: 100%;
  width: 100%;
  position: absolute;
  border-radius: 4px;
}