<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<div id="box01">
<div id="box02">box02</div>
</div>div#box01 {
text-align: center;
}
div#box02 {
width: 300px;
height: 200px;
}