title: Changing the look of new Gnome 3 title bars in with a GTK3 theme
body: <p>I have a GTK3/Metacity theme which uses dark title bars.</p>
  
  <p>Recent versions of Gnome 3 combine title- and toolbars, e.g. in Nautilus. I want to change their color to be consistent with all other GTK windows. </p>
  
  <p><img src="https://i.stack.imgur.com/DSE6i.png" alt="enter image description here"></p>
  
  <p>What is the attribute I need to look for?</p>