.video-embed-field-responsive-video-square-format {
  position: relative;
}

.video-embed-field-responsive-video-square-format:after {
  content: '';
  display: block;
  padding-bottom: 100% !important;
}

.video-embed-field-responsive-video-square-format iframe {
  position: absolute;
  top: 0;
  right: 0;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  margin: 0;
}