@novicell/css-utils/dist/src/embed.css

A CSS utility class package inspired by Bootstrap 4 CSS utilities and configurable via CSS Custom Properties and PostCSS.

/*
// Embed
*/

.embed-responsive {
  position: relative;
  display: block;
  width: 100%;
  padding: 0;
  overflow: hidden;
}

.embed-responsive::before {
  display: block;
  content: "";
}

.embed-responsive > .embed-responsive-item,
.embed-responsive > iframe,
.embed-responsive > embed,
.embed-responsive > object,
.embed-responsive > video {
  position: absolute;
  top: 0;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

.embed-responsive-21by9::before {
    padding-top: 233.333333%;
  }

.embed-responsive-16by9::before {
    padding-top: 177.777778%;
  }

.embed-responsive-4by3::before {
    padding-top: 133.333333%;
  }

.embed-responsive-1by1::before {
    padding-top: 100%;
  }