学着写的一个二级菜单

a
{
     text-decoration: none;
}
a,a:visited
{
    color:#000; background: inherit;
}
body
{
    margin: 0; padding:20px; font-size: 12px;
}
dt
{
    font-size: 22px; font-weight: bold; margin: 0 0 0 15px;
}
dd
{
    margin: 0 0 0 15px;
}
h4
{
    margin: 0; padding: 0; font-size:18px; text-align: center;
}
p
{
    margin: 0; padding:0 0 0 18px;
}
p a, p a:visited
{
    color: #00f; background: inherit;
}
.TreeMenu img.s
{
    cursor: hand;  vertical-align: middle;
}
.TreeMenu ul
{
    padding: 0;
}
.TreeMenu li
{
    list-style: none; padding:0;
}
.Closed ul
{
    display: none;
}
.Child img.s
{
    background: none; cursor: default;
}
#categoryTree ul
{
    margin: 0 0 0 17px;
}
#categoryTree img.s
{
    width: 34px; height:18px;
}
#categoryTree .Opened img.s
{
    background: url(opened.gif) no-repeat 0 1px;
}
#categoryTree .Closed img.s
{
    background: url(closed.gif) no-repeat 0 1px;
}
#categoryTree .Child img.s
{
    background: url(child.gif) no-repeat 13px 2px;
}
#categoryTree
{
    float: left; width:249px; border: 1px solid #99beef; background: #D2E4FC; color: inherit; margin: 3px; padding: 3px;
}