.cabecera_fondo {
	background-image: url(../img/fondo_cabecera.jpg);
	background-repeat: no-repeat;
	background-position: left top;
}
#id_caja_forma_trabajo {
	position: relative;
	width: auto;   
	height: 150px;
	clip: rect(auto,auto,150px,auto);
	overflow: auto;
}