A dark classic theme for X11 desktop environments 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)