Apple has been holding out on us. With MacOS Mojave, Apple finally introduced a system-wide dark mode to Macs that turns the background black and text white in Apple's apps. But there's a darker version of dark mode if you know where to look (and don't mind sacrificing a little color).
Darker dark mode
To enable dark mode, go to System Preferences > General and click Dark at the top for Appearance.
To turn dark mode a shade darker, select the Graphite radio dial for Accent color.
With Graphite selected, the background of apps turns from a charcoal gray to an inkier black.
One side effect of this darker dark mode? The red, yellow and green buttons in the top left of your apps get grayed out.