Hi Spiderstave,
Unfortunately there's no way you can prevent the browser from enlarging the text upon user settings.
This was intended to be used to accessibility, if you were able to stop the text from enlarging, the feature would loose its purpose for the visually impaired users.
Setting its size in Pixels is the most fixed thing you could do, it would actually prevent it from enlarging in IE though, but in FF it acts as it should but now with the zoom feature it should act a lot better than previously when the zoom was text only.
The only way to prevent this is to set everything in Percentage for the whole layout which is impractical in most cases.
