DEDE在文章列表前添加数字序号

css代码部分

以下为引用内容：
<style type="text/css">
<!--
.downtop {
FLOAT: left; OVERFLOW: hidden; WIDTH: 218px; HEIGHT: 278px
}
.downtop UL.text {
MARGIN: 0px 10px; WIDTH: 198px; PADDING-TOP: 5px
}
.downtop UL.text LI {
WIDTH: 198px
}
.downtop UL.text SPAN {
DISPLAY: block; FLOAT: left
}
.downtop UL.text SPAN.num {
MARGIN-TOP: 4px; PADDING-LEFT: 1px; FONT-WEIGHT: bold; FONT-SIZE: 10px; WIDTH: 18px; LINE-HEIGHT: 12px; HEIGHT: 13px; TEXT-ALIGN: center;COLOR: #fff; BACKGROUND-COLOR: #b7b7b7
}
.downtop UL.text LI SPAN.active {
BACKGROUND-COLOR: #7abdff
}
.downtop UL.text SPAN.tit {
PADDING-LEFT: 10px; OVERFLOW: hidden; WIDTH: 168px; WHITE-SPACE: nowrap; HEIGHT: 21px
}
-->
</style>

dede标签部分代码

以下为引用内容：
<DIV class="downtop border">
<UL class=text>
{dede:arclist orderby=pubdate type='commend.' titlelen='26' row='10' channel=3}
<LI>[field:global runphp='yes' name=autoindex]
$a="<SPAN class='num active'>";
$b="</SPAN>";
$c="<SPAN class='num'>";
if (@me > 3) @me = $c.@me.$b;
else @me = $a.@me.$b;
[/field:global] <SPAN class=tit><A title="[field:title/]"
href="[field:filename/]">[field:title/]</A></SPAN></LI>
{/dede:arclist}
</UL>
</DIV>