请教一下 ，论坛首页这个幻灯底下的半透明怎么改长度？







<div class="module cl slidebox">
<ul class="slideshow">
[loop]
<li style="width: {picwidth}px; height: {picheight}px;"><a href="{url}"{target}><img src="{pic}" width="{picwidth}" height="{picheight}" /></a><span class="title">{title}</span></li>
[/loop]
</ul>
</div>
<script type="text/javascript">
runslideshow();
</script>