Nested menu items are barely readable

[sergeyvfx]

Using gray text on gray background is bad idea, especially if one darkens the background with higher nested levels. Here is an example:

https://docs.blender.org/manual/en/dev/render/cycles/settings/scene/render/index.html

"Object Settings" is nearly unreadable there.

[jessetan]

Closing, this is fixed by #638. Please reopen if you disagree.