CSS rule affects Flarum core buttons

https://github.com/justoverclockl/header-slideshow/blob/a8508cd5d6f12696787bf6330192ba010a61329a/less/forum.less#L121-L123

The CSS rule above causes the Flarum buttons to be white, even in light mode, making them barely visible. Disabling the rule in devtools fixes the issue

Possibly related to #3

Inspect less/forum.less lines 121-123 and reproduce the button visibility problem in light mode. Adjust the rule so Flarum core buttons remain visible, then verify that the header slideshow styling still works and the buttons are readable in light mode.

Written by the indexing model from the issue text.