#Popup
{
   visibility: hidden;
   position: absolute;
   left: 50%;
   top: 50%;
   background-color: #FFF;
   padding: 10px;
   z-index: 99;
margin-left:-330px;
}

#Overlay
{
   visibility: hidden;
   position: absolute;
   left: 0;
   top: 0;
   width: 100%;
   background-color: #000;
   z-index: 95;
}