Add ability to change _moz_quote=true color

[the-r3dacted]

Maybe it already exists and I'm just retard, but I can't figure it out without editing it in omni.ja.

This does not work in any file in my theme, even if I make an html.css file. (where the definition is located)

span[_moz_quote=true] {
  color: rgb(51,204,255) !important;
}