Iris Dark is a flat theme that uses varying shades and tones to create distinction and a modern experience. It supports Gtk 3.18 and Gtk 2 (using the Murrine engine).
License: GPL 3.0
2016.08.28: DeviantArt has issues with archives Hopefully fixed
2016.02.03: Fixed minor bug in which window controls did not align properly when placed on the left
2016.02.02: Updated to work with Gtk 3.18, now has a sick new design
2015.04.25: Gtk 3.16 support, fixed Gtk 2 bugs.
2015.02.11: Fixed moar bugs! Gtk 3.14 now supported.
2014.09.04: Fixed many bugs in Gtk 2 treeview, add Nemo theming, fixed Popover issues and added Budgie Desktop theming. Slight changed in menu colours.
2014.08.04: Fixed bugs with Java app menus and distortion of insensitive menu items in Gtk2.
2014.06.23: Hacky support for new aura-based Chrome.
2014.05.10: Updated to Gtk 3.12 and added support for new Unity theming.
2014.03.16: Fixed bugs in Chrome as well as other tweaks.
2014.02.17: Tweaks and experimental Unity CSD support for Ubuntu 14.04
2014.02.02: Fixed bugs with Firefox and tweaked Terminal.