Did you uncheck the box on the Custom CSS page that says "Use Layout's Stylesheet"? Probably, in order to get the rest of your custom theme to work right. (I know because that's exactly how it appeared to me at first before I went overboard with styling it all last night.)

What you are looking at on your icons page now is raw, unstyled code. Everything is displaying as unordered lists as opposed to "inline" or "block". Whoever designed your custom theme didn't make any CSS for the icons page since we couldn't style it previously.

The code I put here should fix the unordered list issue and line up everything neatly, but as said, you might need to adjust margins, padding, and width of everything to fit your theme; and there's no CSS there for customizing the font of anything so you'd have to do that yourself.

I will probably end up typing up a guide of all the specific stuff available for customizing on the icons page...