mthw added a comment.
> ... it seems to do nothing ... The problem was that I tried to use a color name instead of a hex code and put a wrong name there (still don't know the correct one). REPOSITORY R98 Breeze for Gtk REVISION DETAIL https://phabricator.kde.org/D22452 To: mthw, #vdg, #breeze, ndavis Cc: ndavis, zzag, plasma-devel, LeGast00n, jraleigh, fbampaloukas, GB_2, ragreen, Pitel, ZrenBot, himcesjf, lesliezhai, ali-mohamed, jensreuterberg, abetts, sebas, apol, mart