Regular expression to parse any css font

Answering my own question:

/^\s*(?=(?:(?:[-a-z]+\s*){0,2}(italic|oblique))?)(?=(?:(?:[-a-z]+\s*){0,2}(small-caps))?)(?=(?:(?:[-a-z]+\s*){0,2}(bold(?:er)?|lighter|[1-9]00))?)(?:(?:normal|\1|\2|\3)\s*){0,3}((?:xx?-)?(?:small|large)|medium|smaller|larger|[.\d]+(?:\%|in|[cem]m|ex|p[ctx]))(?:\s*\/\s*(normal|[.\d]+(?:\%|in|[cem]m|ex|p[ctx])))?\s*([-,\"\sa-z]+?)\s*$/i

which divides into:

var       parts = rx.exec( str )
  , fontStyle   = parts[1] || 'normal'
  , fontVariant = parts[2] || 'normal'
  , fontWeight  = parts[3] || 'normal'
  , fontSize    = parts[4]
  , lineHeight  = parts[5]
  , fontFamily  = parts[6]
  ;

And yes, I understand that crazy