#nav ul { /* all lists */
  padding: 0;
  margin: 0;
  list-style: none;
}

#nav li { /* all list items */
  float: left;
  position: relative;
}

#nav li ul { /* second-level lists */
  display: none;
  position: absolute;
  top: 1em;
  left: 0;
}

#nav li>ul { /* to override top and left in browsers other than IE, which will position to the top right of the containing li, rather than bottom left */
  top: auto;
  left: auto;
}


#nav li:hover ul, #nav li.over ul { /* lists nested under hovered list items */
  display: block;
}