#mPlayer {
  display: none;
  background: rgba(0, 0, 0, .8);
  position: fixed;
  width: 100%;
  height: 100%;
  z-index: 20;
  left: 0;
  top: 0;
}
/* video player */
#mPlayer div {
  position: fixed;
  background: #000;
  width: 50%; /* width of YouTube Player */
  height: 50%; /* height of YouTube Player */
  left: 50vw;
  top: 50vh;
  transform: translateX(-50%) translateY(-50%);
}