div1 is in the centre of screen and I want div2 in the centre of div1
<div id="div1">
       <div id="div2"></div> 
    </div>
css:
 #div1{ 
     top:0;
     left:0;
     right:0;
     bottom:0;
     margin:auto;
     position:fixed;
     width:595px;
     height:842px;
     background-color:#F0F0F0;
 }
#div2{
}
 
     
    