.altmenu ul { /* do not show submenus by default */
    display: none;
    z-index: 10000;
    position: absolute;
}
.altmenu li a {
    overflow: hidden;
}
.altmenu ul.am-show { /* showing submenu */
    display: block;
}
.altmenu.am-v .am-have-childs, .altmenu.am-h ul .am-have-childs {
    background: transparent url(images/arrow.gif) right center no-repeat;
}