Dropdown Menu with Starkers theme

I am trying to do a drop down menu and it it not working for me. Can someone please look at what I have done and tell me where I am going wrong? I have published each of the pages and set the parent “folio” for each of the drop down links.

The html

<nav>
	<ul>
		<li><a href="#">home</a></li>
		<li>folio
			<ul>
				<li><a href="#">brand</a></li>
				<li><a href="#">identity</a></li>
				<li><a href="#">exhibition</a></li>
				<li><a href="#">illustration</a></li>
				<li><a href="#">philatelic</a></li>
				<li><a href="#">publishing</a></li>
			</ul>
		</li>
		<li><a href="#">contact</a></li>
	</ul>
</nav>

CSS


nav {
	margin-top: 40px;
	font-size: 20px;
	/*background: #ccc;*/
}

nav li {
	display: inline;
	font-family: 'HelveticaNeuel';
	color: rgb(146, 148, 151);
}

nav a {
	text-decoration: none;
}

nav ul li ul {
	padding: 0;
	position: absolute;
	top: 20px;
	left: -30px;
	width: 100px;
	display: none;
	opacity: 0;
	visibility: hidden;
}

nav ul li ul li {
	display: block;
}

Thanks,
Vicki

Ignore, I worked it out. Left the hover state off the css!!!