CSS properties re-calculated when copied

[jasonm]

I noticed that if my textarea has font-size: 10pt that this is converted to font-size: 13px on the div.textoverlay.

My textarea also has a line-height, so I updated the var textareaToOverlay to include line-height. However, the calculated line-height which was applied to the div.textoverlay was 20px, instead of 13px * 1.5 = 19.5px, which causes overlays to become misaligned when they are further down in the textarea.

Is it possible for getStyles to maintain the original units of the CSS properties it copies?