main tool bar transparency

[Demian]

I've used CSS to successfully modify FF 57 to my liking (tabs & bookmark bar under address bar) but the main toolbar has this annoying gray (or semi-transparent) background. My coding skills aren't all that great and I would appreciate any help in getting this eyesore remedied. TIA

UPDATE
Spoke too soon; my solution was:

navigator-toolbox > toolbar:not(#toolbar-menubar) {
background-color: transparent !important;
}

[LIMPET235]

Moving to Firefox Support...