#ytb-video {
  position: relative;
  width: 100vw;
  padding-bottom: 44.79%; /* keep real aspect ratio (860/1920 * 100) */
  height: 0;
  overflow: hidden;
}

#ytb-video video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: contain; /* fit without cropping */
}