Creating a CSS-only dropdown menu - one item disappears

Creating a CSS-only dropdown menu - one item disappears

I've created a CSS-only dropdown menu for my menu in Wordpress using a
tutorial on CSSwizardry (don't have enough reputation to post more than 2
links). I've got it working fine on my homepage: http://www.tarawilder.com
(hover over "Portfolio" to see the items "Design" and "Development").
However, when you go into an interior page, only "development" shows up
and not "design". Go here: http://www.tarawilder.com/portfolio/ for an
example.
Why would that be? I want to rip my hair out, I've been trying to figure
this out all night.
Here is the CSS for the menu (which is technically the same on both pages)
#menu1 {
height: 30px;
}
.menu {
position:relative;
z-index:50;
}
.menu li {
position: relative;
}
.menu a {
display:block;
padding:5px;
color:#fff;
text-decoration:none;
}
.menu ul{
background:#fff;
list-style:none;
position:absolute;
left:-9999px;
}
.menu ul li{
padding-top:1px;
float: left;
padding-top: 10px !important;
}
.menu ul a{
white-space:nowrap;
}
.menu li:hover ul{
left:0;
}
.menu li:hover a{
}
.menu li:hover ul a{
text-decoration:none;
}
.menu li:hover ul li a:hover{
}
Thanks in advance!