Transparent window title bars

[Stewbond]

I have Cinnamon 1.6 installed and I love the Nadia-Dark theme with it's semi-transparent panel.

I've been trying to apply the same sort of theme to the window title bars but I think I'm on the wrong track wrt transparencies. Can anyone point me to how to do this?

So far, this is where I am:
I have my window theme set to Mint-X. I've gone into /home/[user]/.themes/Mint-X/gtk-3.0/gtk.css and changed a bunch of colors to #ff0000. I've confirmed that my titlebar turns red. Next I set these to "transparent" and the titlebars turned black. I figured that this had something to do with excessive shiding and so I went through EVERY .css file in the gtk-3.0 folder and replaced colors with "transparent" and images with "none". The only thing which happened was more and more black as I went through.