Hi Dario,
I was looking at your blog this evening and I noticed the styling issues you were facing with the footnotes. After firing up Firefox and using the CSS tools built into the Web Developer toolbar, I found that adding the following to your skin.css solved some of the styling problems:
.itcexpand-wrapper .itcexpand-html-content { background-color: #c3c3c3;}
body { font-family: Verdana;
font-size: 11px;}
If others are facing a similar problem, there are two principles related to these fixes. One is that the font definition should be assigned to the base body tag in order to define the font that is used in the popup. Second, if a different background color is desired, then the background color can be overridden by setting a custom value for the following class:
.itcexpand-wrapper .itcexpand-html-content
HTH!
Don