#nav_main_system li a,
#nav_main_system li a span {
    font-size:0px;
	text-decoration:none;
	cursor: pointer;
	display: block;
	height: 30px;
	width: 138px;
	overflow: hidden;
	position: relative;
}				
 						
#nav_main_system li.moduly a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 0px;
	left: 0;	
	top: 0;
	width: 115px;
}	

#nav_main_system li.komunikacja a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -30px;
	left: 0;	
	top: 0;
	width: 115px;
	
}

#nav_main_system li.adresowanie a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -60px;
	left: 0;	
	top: 0;
	width: 115px;
}	

#nav_main_system li.klawiatura a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -90px;
	left: 0;	
	top: 0;
	width: 115px;
}		

#nav_main_system li.sterowanie a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -120px;
	left: 0;	
	top: 0;
	width: 115px;
}	



#nav_main_system li.siec span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -150px;
	left: 0;	
	top: 0;
	width: 115px;
}

#nav_main_system li.siec2 span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -180px;
	left: 0;	
	top: 0;
	width: 115px;
}

#nav_main_system li.instalacja span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -210px;
	left: 0;	
	top: 0;
	width: 115px;
}

#nav_main_system li.programowanie span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 -240px;
	left: 0;	
	top: 0;
	width: 115px;
}

#nav_main_system li.przyklady span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0 -270px;
	left: 0;	
	top: 0;
	width: 115px;
}





#nav_main_system li.moduly a:hover span,
#nav_main_system li.moduly#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position:  0 0px;
	width: 138px;
}							

#nav_main_system li.komunikacja a:hover span,
#nav_main_system li.komunikacja#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -30px;
	width: 138px;
}	

#nav_main_system li.adresowanie a:hover span,
#nav_main_system li.adresowanie#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -60px;
	width: 138px;
}	

#nav_main_system li.klawiatura a:hover span,
#nav_main_system li.klawiatura#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -90px;
	width: 138px;
}	

#nav_main_system li.sterowanie a:hover span,
#nav_main_system li.sterowanie#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -120px;
	width: 138px;
}							

#nav_main_system li.siec a:hover span,
#nav_main_system li.siec#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -150px;
	width: 138px;
}	
#nav_main_system li.siec2 a:hover span,
#nav_main_system li.siec2#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -180px;
	width: 138px;
}	
#nav_main_system li.instalacja a:hover span,
#nav_main_system li.instalacja#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -210px;
	width: 138px;
}	
#nav_main_system li.programowanie a:hover span,
#nav_main_system li.programowanie#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -240px;
	width: 138px;
}	
#nav_main_system li.przyklady a:hover span,
#nav_main_system li.przyklady#active a span {
	background-image: url(../img/dzialanie_menu.png);
	background-position: 0px -270px;
	width: 138px;
}