#nav, #nav ul { padding: 0; margin: 0; list-style: none; } 

#nav a { display: block; width: 10em; } 

#nav li { float: left; width: 10em; }

#nav li ul { position: absolute; width: 10em; left: -999em; } 

#nav li:hover ul { left: auto; color: red; background: black; }

#nav li:hover ul, #nav li.sfhover ul { left: auto; }