The background image appears in all browsers, but not in Firefox. This
also seems to imply, the code and style is really correct.
I tracked this down in Firefox and Safari. In Safri [using WebInspector], the style
is there and so, the browser shows it. In FF [using Firebug], the style is missing and so,
naturally [??] it is not displayed. I even tried another machine with FF4 and FF3.6x and
NO Firebug and other extensions installed and it is the same.
For me, it looks like - for what reason ever - ext [I am using 3.4] - removes
the style [or why should they disappear in Firebug??].