Re: [CSS21] computed value of 'font-weight' is not precisely defined

L. David Baron wrote:
> CSS 2.1 added the following text:
>   # The computed value of "font-weight" is either:
>   #
>   #    * one of the legal number values, or
>   #    * one of the legal number values combined with one or more of
>   #      the relative values (bolder or lighter). This type of
>   #      computed values is necessary to use when the font in
>   #      question does not have all weight variations that are
>   #      needed.
> http://www.w3.org/TR/2007/CR-CSS21-20070719/fonts.html#font-boldness
> 
> This text doesn't say what specified values lead to these computed
> values.  It is, in fact, ambiguous, and could lead to two different
> sets of results, as explained below.

The CSSWG decided not to define this in CSS2.1, and I was given an
action item to write a note that basically says that. Here's a
proposed note:

   Note: A set of nested elements that mix 'bolder' and 'lighter' will
   give unpredictable results depending on the UA, OS, and font
   availability. This behavior will more precisely defined in CSS3.

~fantasai