[Deff]

<style type="text/css">
#div1{
   position:relative;
   top:60px;
   height:300px;
   width:300px;
   margin:0 auto;
   border:2px solid blue;
}
#div2{
   position:relative;
   height:200px;
   width:200px;
   top:50%;
   margin:-100px auto 0 auto;
   background:#FF3CEE;
   border:2px solid red;
}
</style>
<div id=div1>
	<div id=div2>
      и в нём div поменьше,
	</div>
</div>