div#mask {  
  position: fixed;
  display: none;
  
  /* IE 8 */
  -ms-filter: "progid:DXImageTransform.Microsoft.Alpha(Opacity=50)";

  /* IE 5-7 */
  filter: alpha(opacity=70);

  /* Netscape */
  -moz-opacity: 0.7;

  /* Safari 1.x */
  -khtml-opacity: 0.7;

  /* Good browsers */
  opacity: 0.7;
  background-color: #555555;   
}
img#popup_loader {
  position: fixed;
}
div.popup_wrapper {
  position: fixed;
  display: none;
  background-color: #ffffff;
}