.IMGresponsive {
  width: 100%;
  height: auto;
  display: block;
    margin-left: auto;
    margin-right: auto;

}

.video-responsive {
 overflow:hidden;
 padding-bottom:56.25%; 
 position:relative;
 height:0;
}
.video-responsive iframe {
 left:0;
 top:0;
 height:100%;
 width:100%;
 position:absolute;
}