It can be done in Fedora with the Gnome 3 theme: http://fedoramagazine.org/make-firefox-look-native-fedora/

It should be like this:


[![enter image description here][1]][1]

but it looks like this:

[![enter image description here][2]][2]


  [1]: https://i.sstatic.net/3whBJ.png
  [2]: https://i.sstatic.net/NwFPV.png