.popup {
  position:absolute;
  z-index:2000;
  top:0;
  left:0;
  width:100%;
  height:100%;
  background:rgba(0,0,0,0.7);
  opacity:0;
  visibility:hidden;
  transition:.3s ease;
}

.show-popup .popup {
  opacity:1;
  visibility: visible;    
}

.popup > iframe {
  position:absolute;
  top: 25%;
  left: 50%;
  margin-left: -370px;
}