Yui, how to remove the margins for a 2 column layout?

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
 <HEAD>
  <TITLE>testing</TITLE>
  <!-- css -->
<link rel="stylesheet" type="text/css" href="http://yui.yahooapis.com/2.5.2/build/reset-fonts-grids/reset-fonts-grids.css">
<!-- js -->
<script type="text/javascript" src="http://yui.yahooapis.com/combo?2.5.2/build/utilities/utilities.js"></script>
<style>
.yui-b {
	background-color: #eeeeee;
}


</style>
 </HEAD>

 <BODY>
  <div id="doc3" class="yui-t1"> <!-- change class to change preset -->
		<div id="hd">header</div>

		<div id="bd">
	      <div id="yui-main">
		 <div class="yui-b">
			 bd.main
			 </div>
	      </div>

		  <div class="yui-b">bd.other</div>
		</div>

		<div id="ft">footer</div>
	</div>
 </BODY>
</HTML>