Dont know the complete problem just making a guess this is what w3c is providing the tips -
Do not specify the font-size in pt, or other absolute length units for screen stylesheets. They render inconsistently across platforms and can't be resized by the User Agent (e.g browser). Keep the usage of such units for styling on media with fixed and known physical properties (e.g print).
Just go through the whole page http://www.w3.org/QA/Tips/font-size and provide more specific information if problem is not solved.
PS: Anonymous user problems attract less attention so register and ask.