.video_container{
    width: 100vw;
    height: 100vh;
}
iframe{
    position: absolute;
    top: 50%;
    left: 50%;
    width: 100vw;
    height: 100vh;
    transform: translate(-50%, -50%);
}
@media (min-aspect-ratio: 16/9) {
    .video-container iframe {
      /* height = 100 * (9 / 16) = 56.25 */
        height: 56.25vw;
    }
  }
      
@media (max-aspect-ratio: 16/9) {
    .video-container iframe {
      /* width = 100 / (9 / 16) = 177.777777 */
        width: 177.78vh;
    }
}