The black text on black background issue is a fault generally specific to websites, as many specify the font colour, but regret to specify the background colour.

This also comes with rich text usage in labels
Internally it's a QTextBrowser then and the colors are handled by some css which apparently just assumes "black on white".
I've once or twice tried to fix that in bespin, but it occasionally gets reset

Rule of thumb: if you can select the text with the mouse, it will likely have the wrong color.