关于添加css样式的问题

<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<style type="text/css">
#menu {
width:1000px;
margin:0 auto;
height:65px;
background:#000;
font-size:12px;
}
#menu A {
color:#FFF;
text-decoration:none;
}
#menu A:hover {
font-size:16px;
}
#menu SPAN.current {
border-right:#0F0 1px solid;
width:100px;
float:left;
line-height:65px;
COLOR: #fff;
text-align:center;
}
.selected {
background:#C60;

}
</style>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.2/jquery.min.js"></script>
<script type="text/javascript">
$(function(){
   
    $("span").click(function () {
                                                     $(this).each(function(){
                                                                              $(this).toggleClass("selected");
                                                                            });
                                 })
   
   

  
   
          })
</script>
<title>无标题文档</title>
</head>
<body>
<div id="menu"> <a href=""><span class="current">首页</span></a><a href=""><span class="current">关于</span></a><a href=""><span class="current">招聘</span></a></div>
</body>
</html>问题:点击后为何背景没有变色？