Let me clear any possible misunderstandings in regards to the CSS files - This is FLASH, and the only thing that CSS can control, is the TEXT itself. It doesn't have any impact on the layout of the gallery in general.
CSS in flash is about one thing: Formatting TEXTFIELDS. You can't use CSS in any other way simply because flash doesn't work like that(like html). TEXTFIELDS are adopted in flash to work similar(but still inferior) to normal HTML. That means it supports basic HTML tags and basic CSS formatting- You can't control anything outside of the textfield with CSS, and generally its limited to stylizing the the text.