html,body{
  height:100%;
  margin:0;
  background:#000;
  overflow:hidden;
}
.responsive{
  position:absolute;
  top:50%;
  left:50%;
  transform:translate(-50%,-50%);
  max-width:100%;
  max-height:100%;
  height:auto;
  display:block;
  user-select:none;
  -webkit-user-drag:none;
}