Many buttons on MO currently have white text on a light grey background, like this:
(at least on my browser). The text is not very visible, and moreover this color scheme is often used for inactive/disabled buttons, so it is easy to think subconsciously "I cannot click this button, there must be a reason why it's disabled and I can't perform this action". I find this misleading.
Has the color scheme been changed recently? I don't recall it being this way.
Anyway, I suggest to change the text to black, like in the example below; I think it would be much more visible and less misleading.