nav, #nav ul { /* todos */
  padding: 2px;
  list-style:none;
  /*line-height: 1px;*/
  z-index:2;
}

#nav a {
  display: block;
  z-index:2;
}

#nav li { /* items nivel 1 */
  float: left; 	
  list-style:none;
  z-index:2;
}

#nav li ul { /* fondo items 2 nivel */
  position: absolute;
  width: 250px;
  left: -999em; /* using left instead of display to hide menus because display: none isn't read by screen readers */
  z-index:2;
}

#nav li ul ul { /* fondo items 3 nivel */
  margin: -1em 0 0 10em;
  z-index:2;
}
#nav li ul li { /* items 2 y 3 nivel */
  width:200px;
  height:20px;
  text-align:left;
  z-index:3;
}

#nav li:hover ul ul, #nav li:hover ul ul ul, #nav li.sfhover ul ul, #nav li.sfhover ul ul ul {
  left: -999em;
}

#nav li:hover ul, #nav li li:hover ul, #nav li li li:hover ul, #nav li.sfhover ul, #nav li li.sfhover ul, #nav li li li.sfhover ul { /* lists nested under hovered list items */
  left: auto;
}

#content {
  clear: left;
  width:900px;
  z-index:1;
}