GnomishDark is a clean dark theme for GTK3. It also contains a GTK2 theme, that depends on the latest Murrine and Pixmap engines.
*** Current Dependencies ***
GTK3 = 3.12.X (works with 3.10 too)
gtk2-engines-murrine >= 0.98.1.1 (for GTK2)
gtk2-engines-pixbuf >= 2.24.10 (for GTK2)
Metacity >= 2.34 (for GTK2)
*** Notes ***
1) Ubuntu users could disable "overlay-scrollbar" if they want to have the original scrollbars of the theme. See help.ubuntu.com/12.10/ubuntu-h…
2) Don't forget to take a look at the file "README" in the theme folder. It contains useful tips for LibreOffice, Firefox, Epiphany, etc.
3) Light monochromic icons go well with this theme. I've made the gray version of nouveGnome tsujan.deviantart.com/art/nouv…
Mar 4 2014
Added a matching Unity theme for Ubuntu Trusty.
Apr 14 2014
Updated for GTK+-3.12 (still works with 3.10).