It supports GTK2, GTK3, Cinnamon, GNOME, Openbox, Xfwm.
1.GTK >=3.20
2.Murrine engine — The package name depends on the distro.
..*gtk-engine-murrine on Arch Linux
..*gtk-murrine-engine on Fedora
..*gtk2-engine-murrine on openSUSE
..*gtk2-engines-murrine on Debian, Ubuntu, etc
Just copy dark knight/dark knight compact folder to /home/{username}/.themes.
Make .themes folder if needed.
Icons i used was Papirus dark
Inspired by vastglad
This theme is based on materia theme
Made with Themix GUI theme designer