Your font-sizes are fine.... it's just IE seems to interpret a pixel differently than FF.... it's not that noticable. The main noticible thing is the fact that the spacing is different in lists. Most likely a padding/margin issue, and not a font-size. You might try setting the font-size to just an "em" size (1 being normal point, 0.9 being 90% of normal, 1.2 being 120%). That would work better cross-browser 😉