.video-responsive-4-3 {
  height: 80vh;
  max-width: 90vw;
  width: calc(75vh * 0.75); /* 4:3 aspect ratio */
  overflow: hidden;
  position: relative;
  margin: 0 auto;
  border-radius: 10px;
}

.video-responsive-4-3 video,
.video-responsive-4-3 iframe,
.video-responsive-4-3 object,
.video-responsive-4-3 embed {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
}