How to display inline my sub menu

Hi everybody...i have an issue.
Here into my blog i've inserted a sub-menu (categories).
i wanna that the sub-menu categories display inline...
this is my css:
div#menu1 ul.sub-menu, div#menu1 ul.rMenu-ver {
border: dotted #000000;
background:url("http://designblog22.altervista.org/wp-content/themes/atahualpa/images/opacity.png") no-repeat scroll left!important;
float: left;
list-style: none;
display:inline;
}

Obiviously it doesn't work.
Can someone please help me?

I'm using the latest version of wp and atahualpa 3.7.1

link to the blog: http://www.tuttologist.com/