Currently the new accent colour feature sets the hover and focus colours to be the same. It would be better if the hover colour was set to a modification of the focus colour with reduced saturation. This is how it is done in the Breeze colour scheme. This current implementation is simply enforcing what I see as a design/usability regression from Breeze Light and Breeze Dark on all colour schemes, making the accent colour feature quite unappealing.
I worked around this in my own C++ window decoration by doing the following: if(buttonFocusColor == buttonHoverColor) buttonHoverColor = ColorTools::getDifferentiatedLessSaturatedColor(buttonHoverColor); QColor ColorTools::getDifferentiatedLessSaturatedColor( const QColor& inputColor ) { int colorHsv[3]; inputColor.getHsv(&colorHsv[0], &colorHsv[1], &colorHsv[2]); if( colorHsv[1] > 125 ) colorHsv[1] -= 80; //decrease saturation if not already low else colorHsv[1] += 80; // else increase saturation if very low to provide differentiation/contrast QColor outputColor; outputColor.setHsv(colorHsv[0], colorHsv[1], colorHsv[2]); return outputColor; } I have to still apply this in several other places in the application style where hover and focus colours are the same, and it would be better if I didn't have to do this at all.
Seems reasonable to me. Feel free to submit a MR that fixes it, as well as a separate one to fix the color issues in Breeze Light and Breeze Dark.
OK, I will take a look at this soon. I have came up with some different saturation thresholds than I posted in the code above, which work better with all the standard system accent colours, so will try to port them to Plasma.