dropdown menu

hello, I have design a dropdown menu But it is not working can any one tell me what is the wrong in this code.

<html>

<head>

<style type="text/css">


/*Credits: Dynamic Drive CSS Library */

/*URL: http://www.dynamicdrive.com/style/ */


.arrowgreen{

	width: 180px; /*width of menu*/

	border-style: solid solid none solid;

	border-color: #94AA74;

	border-size: 1px;

	border-width: 1px;

}


.arrowgreen ul{

	list-style-type: none;

	margin: 0;

	padding: 0;

}

	

.arrowgreen li a{

	font: bold 12px Verdana, Arial, Helvetica, sans-serif;

	display: block;

	background: transparent url(media/arrowgreen.gif) 100% 0;

  height: 24px; /*Set to height of bg image- padding within link (ie: 32px - 4px - 4px)*/

	padding: 4px 0 4px 10px;

	line-height: 24px; /*Set line-height of bg image- padding within link (ie: 32px - 4px - 4px)*/

	text-decoration: none;

}	

	

.arrowgreen li a:link, .arrowgreen li a:visited {

	color: #5E7830;

}


.arrowgreen li a:hover{

	color: #26370A;

	background-position: 100% -32px;

}


	

.arrowgreen li a.selected{

	color: #26370A;

	background-position: 100% -64px;

}


</style>


</head>

<body>

<div class="arrowgreen">

	<ul>

		<li><a href="http://www.dynamicdrive.com" title="Home">Home</a></li>

		<li><a href="http://www.dynamicdrive.com/style/" class="selected" title="CSS">CSS Library</a></li>

		<li><a href="http://www.ddwhois.com" title="Whois">DD Whois</a></li>

		<li><a href="http://www.dynamicdrive.com/forums/" title="Forums">Forums</a></li>

		<li><a href="http://tools.dynamicdrive.com/" title="Tools">Webmaster Tools</a></li>

		<li><a href="http://www.javascriptkit.com" title="JavaScript">JavaScript</a></li>

	</ul>

</div>

</body>

</html>