Basically, the mouseover effect changes when you click on either the black, random color or darken button in the navigation. When you change from darken to black, the black doesn’t override the darkened grids, however, when you switch from black to darken, the darken effect overrides the black grids.
I’ve tried to play around with opacity, but I just can’t seem to get it to work. Not sure if I explained this well, but the link provided below should clarify the problem. Appreciate any help. Links attached below.