A dark theme optimized for speed and to be low on system resources that is known to work with: MATE, Cinnamon, Xfce, Unity, Openbox and LXDE.
* Stays in the background to focus on tasks
* Lightweight (only ~50kb, Adwaita has ~1200kb)
* Strong borders around widgets for usability (like traditional styles, unlike material & Co.)
* Easy install (at least if you use a debian based distribution)