I came across this annoying off by one pixel layout issue several days ago when dealing with <code> tags. You may not even guess that its caused by it at first, but if you ever try to test your layout with a baseline script, you may notice this.

Take a good look at the following screenshot and tell me, are these two paragraphs the same height?

The correct answer is No. They’re not. If you look at the line height, the font size, almost everything you’ll find that these two paragraphs are exactly the same with the exception of the <code> tags in the second paragraph. Digging in deeper you’ll see the following problems with the paragraph height:

Four. Pixels. Taller. *explicitive*. Most people wouldn’t care, or even notice unless you were using a baselineing tool like Typesetter. The solution, after much digging around, is to set the line height of <code> tags to zero.

code {
     line-height: 0;
}

And like magic, all of a sudden your paragraphs now behave correctly. This may be classified as a bug, at the very least, its an annoyance, but if you find yourself having problems with your paragraph line heights not behaving quite right, take a look and give this a shot.