The usage of Google fonts only works when using one font per Style.Include. Using multiple fonts, separated by a vertical line | (usage provided like this by Google) results in a server error. The vertical line is causing the error. As soon as it's removed,
the code works fine (obviously the fonts are not included then).
'http:/fonts.googleapis.com/css' is not a valid virtual path.
The error occurs in ResourceManager.cs in function FixPath, line 42. It seems the VirtualPathUtility.ToAbsolute() doesn't handle the vertical line very well.