I want to change the colour of the horizontal menu bar. Currently, the existing options under the “Graphene Options” only allows two choices: to use the regular black colour, or to use “light-coloured header bars” (which is essentially grey). How can I change it to another colour? Also, if I want to go a little more fancier, how can I implement the “dithering” effect on the menu bar, where it fades from one colour to another?