[Plone-UI] Space between Portal Tabs

[Enzo Cesanelli]

This is an issue I can't resolve since Plone 2 and now it goes on with Plone
2.1.

There's always a space between the portal tabs I can't delete, even if
padding, border and margin are setted to zero.

This time I customized the portal tabs with css rollover images as described
in the limi's tutorial:
http://plone.org/documentation/how-to/replacing-tabs-with-images

Everything works well (but the delay to show the rollover images the first
time... but this is another story) except for the space between the portal
tabs.

This is the related code:

ul#portal-globalnav {
    height: 33px;
}

ul#portal-globalnav li {
    display: block;
    float: left;
    border-collapse: collapse;
    padding: 0;
    margin: 0;
    overflow: hidden;
    background-repeat: no-repeat;
    height: 33px;
}
ul#portal-globalnav li a,
ul#portal-globalnav li a:hover,
ul#portal-globalnav li.selected a {
    display: block;
    padding: 33px 0 0 0;
    border: 0;
    height: 0px !important;
    height /**/:33px;
}
li#portaltab-index_html a {
    background-image: url(&dtml-portal_url;/home.jpg);
    background-position: 0px 0px;
    width: 93px;
}
li.selected#portaltab-index_html a:hover,
li#portaltab-index_html a:hover {
    background-image: url(&dtml-portal_url;/home_over.jpg);
    background-position: 0px 66px;
    width: 93px;
}
li.selected#portaltab-index_html a {
    background-image: url(&dtml-portal_url;/home_over.jpg);
    background-position: 0px 33px;
    width: 93px;
}

And so on...
As you see I also added the "border-collapse: collapse;" option (I know is a
teble attribute but I hoped...) without any success.
If you know the solution to this question, speak please!
Enzo