FYI, I am not using grids.css... just parts of fonts.css...
Additionally, I am not sure how you would account for quirks mode with
** 84.5% for !IE, keywords for IE
** Percents could work for IE, but for backCompat purposes, we are using
** x-small is for IE < 6 and IE6 quirks mode.
I am personally using a strict DTD, so no need for me to worry about
Also, I vaguely remember reading somewhere (in this lists archives) that
you can use a strict (or was it transitional... or both?) DTD with the
YUI CSS library and avoid quirks mode altogether.