#mask {
  position:absolute;
  left:0;
  top:0;
  z-index:9000;
  background-color:#000;
  display:none;
}  
#boxes .window {
  position:absolute;
  width:440px;
  height:auto;
  display:none;
  z-index:9999;
  border-radius: 15px;
  text-align: center;
  left: 50% !important;
  top: 50% !important;
  transform: translate(-50%, -50%);
}