Numeric values not recognized for font-weight

Example: using default settings, direct input of

h2 { font-weight: 600; }

causes the error message

Value Error : font-weight 600 is not a font-weight value : 600

This seems to happen for all numeric values, i.e. only keyword values 
like bold are accepted for font-weight. Happens in checking via URL too, 
and when using CSS level 3.

So it looks like a bug in the routine for parsing font-weight value.

-- 
Yucca, http://www.cs.tut.fi/~jkorpela/