一个position定位问题

<style type="text/css">
    #Analystlist li{height:30px;}
    #Analystlist .fl{float:left;}
    #Analystlist .fr{float:right;}
    .pj{
        position:relative;
        border:#CCC 1px solid;border-bottom:#FFF 1px solid;padding:0 5px 0 5px;margin-left:10px; 
    z-index:1;}
    .pj_box{position:absolute;width:200px;height:200px;border:#CCC 1px solid;color:#FFF;;
    background:#999;
    right:-1px;
    top:16px;
    z-index:2;
    }
</style>

      <div class="r_box" style="width:200px;">
        <div class="r_title"><span class="fl">用户评价</span></div>
        <div class="list nb">
            <ul id="Analystlist">
            <li t='1' class='on'><span class="fl">用户1</span><span class="fr pj">评价<div class="pj_box">评价1</div></span><span class="fr">3.4 </span></li>
            <li t='1' class='on'><span class="fl">用户2</span><span class="fr pj">评价<div class="pj_box">评价2</div></span></div><span class="fr">3.4 </span></li>
            </ul>
        </div>
    </div>