div.popup_gallery{width:100%;height:100%;background:url(Images/black_40_opacity.png);position:fixed;top:0px;left:0px;z-index:2;display:none;}
div.popup_gallery div.popup_frame{width:800px;height:600px;margin:-300px 0 0 -400px;background-color:white;border:3px solid white;position:absolute;top:50%;left:50%;}

/* buttons */
div.popup_gallery .close_btn{width:35px;height:35px;background:url(Images/close_popup.png) no-repeat top left;display:block;position:absolute;top:-3px;right:-38px;cursor:pointer;}