warning on lightgrey

sass is turning my hex color into 'lightgrey', which is causing a warning in css lint. I think lightgrey should be legal so I filed this css lint issue:
https://github.com/stubbornella/csslint/issues/407

I was told the actual fix would be in this repos so filing this here.

here's a spec, I think it applies
http://www.w3.org/TR/css3-color/#svg-color
