This happens when you are using ems with nested elements. In your case the span is nested in the div.post. You are essentially multiplying 1.4em by 1.1em making it 1.54em in size. You will want to either explicitly name the size (11px, in this case) or figure out how to get it to 11px by "multiplying" 1.4ems. Try .8em for your span element and you should achieve your desired effect.