#sidebar-a {background:#CCCCCC; float:right; line-height: 19px; width: 240px; height:350px;text-indent:1cm; padding:10px;}
#content {padding: 30px; background:#FFCCFF; line-height: 18px; width:400px; height:310px; overflow:hidden; float:left;}
.clear {clear:both;}
<div class="clear"></div>
