#demoIzq, #demoDer, #demoMed {  width:370px; background-color:#EAEAEA; text-align:center; margin:0 1px 0 1px; }

#demoDer, #demoMed { float:left; }

select {
	width:370px;
	font-family: Arial, Tahoma;
	font-size: 11px;
}