margin-top:
float:left; background:#eee;
float:left; background:#ccc;
width:400px; clear:left; background:#aaa; margin-top:10px; (margin-top not "working")
margin-bottom:
float:left; background:#eee; margin-bottom:10px;
float:left; background:#ccc;
width:400px; clear:left; background:#aaa;
control (w/o float):
background:#ccc;
background:#aaa; margin-top:10px;