OFF:

Please do not use gray fonts on light background. Black is fine, really. Dark gray is acceptable for background of dark themes since it usually a compromise between contrast and hurting the eye by making the reader's pupils to dilate. There is no such compromise for light themes (well, if you don't count readablity <-> design and your really should weight readability much more).

It's not this article only, but this article made me to change the color in the developer console.