.semaforo {
	width:16px;
	height:16px;
	background-image: url("semaforos.png");
	background-repeat: no-repeat;
}

.semaforo.gris 		{ background-position-y: 0px; 		}
.semaforo.rojo 		{ background-position-y: -17px; 	}
.semaforo.amarillo 	{ background-position-y: -34px; 	}
.semaforo.verde 	{ background-position-y: -51px; 	}