Arc-BLACKEST is a flat, dark-mode theme with transparent elements, for GTK, xfwm4, openbox-3, GNOME-Shell, and Cinnamon desktop environments. Black-on-black-on-black, with a single, enhanced-Arc-blue color right where you want it.
Inspired by BWnB for KDE Plasma and Windows, this popular scheme now lets GTK users "Embrace the darkness" (2kabhishek.github.io/BWnB).
Arc-BLACKEST's, BWnB, scheme is promoted as "a true black color scheme" with enhanced-Arc-blue accents. Moreover, the original designer claims it to be "Darker than any other dark theme out there" (2kabhishek.github.io/BWnB). BWnB now themes all the latest GTK platforms, including GNOME 3.36 and its contemporaries.
Arc theme is 2020's most popular theme, as it has been for the past couple of years, according to major sources (https://itsfoss.com/best-gtk-themes//' https://www.ubuntupit.com/top-15-best-gnome-shell-themes-gnome-desktop/; https://www.ubuntupit.com/best-ubuntu-themes-will-blow-mind/).
The well-embraced standard Arc theme has always been available in the three variants of Arc, Arc-Dark, and Arc-Darker; but, at last, the darkest dark-Arc of them all has arrived on the GTK+ scene: BWnB-GTK.
Special thanks to horst3180 @ "https://github.com/horst3180/Arc-theme" for initially advancing Arc, and for all the inspiration that notion forwards. Further thanks to NicoHood at: https://github.com/NicoHood/arc-theme, for keeping Arc alive and great, more currently. Tremendous thanks, also, to Abhishek Keshri @ "https://github.com/2KAbhishek" for the inspiration and guidance in finally making the BWnB scheme available on the GTK platform.
Manual Installation Is Easy:
Extract the ".zip" file into your "~/.themes/" folder - to install for current user only - or into the "/usr/share/themes/" folder - for the theme to be applied globally. 2) Use the GNOME Tweak Tool or an equivalent app to enable it for your desktop.
If installing manually, make sure to install the dependency: "Murrine theme engine" if you do not already have it; and update your GTK+packages if you have not.
Logging out and then logging back in may be necessary on some operating systems to fully implement theme.