can't get a tab to show up

at this site, i'm trying to have a tab appear over my banner.

here is what my css looks like

#top {
	position: absolute;
	bottom: 0px;
	left: 0px;
	}
#top ul {
	float: left;
	list-style-type: none;
	margin: 0;
	padding: 0;
	width: 100%;
	}
#top li {
	display: none;
	float: left;
	}	

#top li a.art {
	background: transparent url (/wp-content/themes/remember/img/arttab.png) no-repeat scroll left top;
	width: 129px;
	height: 75px;
	}

Code (markup):

and here is what my html looks like;

<div id="container"><!-- start container -->


   <div id="header">    <!-- start header -->
    <div id="banner">
	 	<div id="top">
		<ul>
			<li><a class="arttab" href="#"></a></li>
			</ul>
		</div>
		</div>

	</div> <!-- end header-->

Code (markup):

does anyone know what I'm doing wrong?

this is the tab that I'm trying to get show up.

 

Code looks alrite.
I'm guessing the is the image path.

Try
background: transparent url (img/arttab.png)

 

unfortunately, that doesn't work either as i've tried that type of variation.