Board Thread:Support Requests - Getting Technical/@comment-1295676-20130302210454/@comment-3335785-20130302222438

This appears to be a simple case of a non-specific selector. a.button { color:#fff !important; } Will fix the issue for all buttons (which I don't think are used all that much in monobook).

Should you wish to style buttons further you can use that selector to add a background colour, a border, change the colour of the text (I've set it to the default white above) and so on.