div.x{
     width: 450px;
     height: 600px;
     position: absolute;
     top: 1px;
     left: 0px;
     z-index: 1; 
     background-image: url(popup.jpg); 
     background-repeat: no-repeat;
}

div.y{
      width: 20px;
      height: 20px;
      position: absolute;
      top: 1px;
      left: 430px;
      z-index: 1; 
      background-image: url(x.jpg);
      background-repeat: no-repeat; 
      cursor: pointer;
}