/* Z-index of #mask must lower than #boxes .window */  
#mask {  
  position:absolute;  
  z-index:9000;  
  background-color:#000;  
  display:none;
  top:0;
  left:0;
}  
   
#boxes .window {  
 position:absolute;  
 width:800px;  
 height:600px;  
 display:none;  
 z-index:9999;  
}  
 
 
/* Customize your modal window here, you can add background image too */  
#boxes #dialog {  
 width:300px;   
 height:200px;  
 background-color:white; 
}