Heading sizes don't change

Neither changing the Custom CSS in the Design tab nor adjusting the sizes on the typography page changes the size of my h2 and h3 headers. Right now, the h2 headers are smaller than the h3, even though they’re spec’ed at 1.5em and 1.2em, respectively. Changing the sizes in either the Custom CSS or the Typography tab doesn’t do anything, regardless of what I enter. I’m also having a problem that some of the Custom CSS ‘font-weight’ commands work, but some don’t.

This page
http://brokengirl.info/2012/04/04/dissecting-a-cover-design-part-one/
demonstrates the problem: after the title, the next header (the museo-slab one) is h2, the next is h3.

Thanks. I love the theme!