.sup_izq {
	background-image: url(imagenes/back_img_izq_sup.jpg);
	background-position: right top;
}
.sup_der {
	background-position: left top;
	background-image: url(imagenes/back_img_der_sup.jpg);
}
.inf_der {
	background-image: url(imagenes/back_img_der_inf.jpg);
	background-position: left top;
}
.inf_izq {
	background-image: url(imagenes/back_img_izq_inf.jpg);
	background-position: right top;
}
.cont_izq {
	background-image: url(imagenes/back_img_izq_cont.jpg);
	background-position: right top;
}
.fondo_end {
	background-image: url(imagenes/back_end.jpg);
	background-repeat: no-repeat;
	background-position: top;
}

.cont_der {
	background-image: url(imagenes/back_img_der_cont.jpg);
	background-position: left top;
}
.crono_izq {
	background-image: url(imagenes/back_img_izqend_crono.jpg);
	background-position: right top;
}
.crono_der {
	background-image: url(imagenes/back_img_derend_crono.jpg);
	background-position: left top;
}