Why is style in a span not affecting my text?

On http://beachwheelsaustralia.com/38-cm-polyurethane-foam-tuff-tire-wheel/, the text 20 mm bushing is wrapped in <span class="besideAddToCart">20 mm bushing</span>. And in style.css I have
.besideAddToCart {
vertical-align: middle;
}
I'm trying to move that text up a bit.
But in Firebug, .besideAddToCart isn't listed as a style affecting that span.
I don't get it. How come I can't wrap text in a span with a class and have that style work?

Is something in WordPress overriding this?

Thanks,

Scott