Help with S2 styles

cuthbertcross says my journal displays as black-on-black for her. For me it's a perfectly sensible, fairly minimal, black-on-white.

It's the style called 'A sturdy gesture' under the S2 style system, and it's in the default theme (plain black and white), although now I've prodded it a bit more, it turns out that the 'preview' page shows it with solid black title boxes at the top of each entry box, and I don't seem to have that, but still.

Anyone got any ideas why my journal doesn't like cuthbertcross?