.ms-lightbox-template{
max-width:750px;
padding:5px 5px 0.1px 5px;
margin:0 auto;
background:#000;
}

.ms-lightbox-template .ms-lightbox-btn{
 position:absolute;
 bottom:20px;
 right:20px;
}
.ms-lightbox-template .ms-lightbox{
 text-indent:9999px;
 display:block;
 width:55px;
 height:52px;
 margin:-42px;
 background:url(lightbox-btn.png) no-repeat center;
}