A recolored version of FlatStudio GTK theme with Base16 Eighties/Tomorrow Night Eighties colorscheme in mind.
Just clone the repo, drop the folder on /usr/share/themes and use a program to change the theme(I recommend xfce-theme-manager).
Some applications doesn't work quite well with dark gtk themes(Firefox, Thunderbird, Liferea, Monodevelop to name a few) so it's highly recommended to override your current GTK theme and make the application load another gtk theme, if you use XFCE you can modify the launchers through menulibre like this(or mannualy edit the launchers at ~/.local/share/applications/):
zsh -c "GTK_THEME=/usr/share/themes/Numix/gtk-3.0/gtk.css firefox %u"
zsh -c "GTK_THEME=/usr/share/themes/Numix/gtk-3.0/gtk.css thunderbird %u"
zsh -c "GTK2_RC_FILES=/usr/share/themes/Numix/gtk-2.0/gtkrc libreoffice5.0"
If you use bash, just change "zsh -c" to "bash -c".
Author: Rafa Cobreros
License: GPL
http://gnome-look.org/content/show.php/FlatStudio?content=154296
Author: Chris Kempson
License: MIT
https://github.com/chriskempson/base16
https://github.com/chriskempson/tomorrow-theme