body {
	vertical-align: top;
}
#madre {
	z-index: 1;
}

#madre_menu{
	position:relative; /*set to a negative number 1/2 of your width*/
	z-index: 159;
	top: 0px;
	overflow: visible;
	height: 50px;
	width: 900px;
	left: 20px;
}
#madre_contenido {
	position:relative;
	top: 70px;
	left: 215px;
	width: 600px;
	z-index: 59;
	text-align: left;
	visibility: visible;
}

.centrar {
	text-align: center;
}