I have a close graphic button which is gray. The button turns to black (#000) on hover. The background is white. In high contrast black mode in Windows 10, the background is the reverse of white, black. The button is gray, which I think is the reverse of its color in normal mode. But on hover, the button, which is supposed to be rendered with the color reverse of black, is actually rendered black (#000) and turns out invisible in the black background. The same problem is observed for active and focus pseudo-classes of the same button. And the problem also exists for the box-shadow property of ::before pseudo-element.