It's Apple by a nose. Windows 10 will soon have a dark mode, but Mac users can get a system-wide dark mode now with MacOS Mojave. 

Here's how to enable dark mode and what it does and doesn't do to your Mac's UI.

Mojave dark mode

Apple introduced some semblance of a dark mode with OS X Yosemite, but it turned only the menu bar and the Dock dark. Mojave does dark mode right. On most of Apple's own apps, it turns the background black and text white. The Photos app and iTunes, in particular, look great in dark mode -- the colors of your photos and album art really pop against the black background.

Dark mode's impact is felt less in Safari. In Apple's browser, the title bar at the top turns black but web pages are displayed in the same manner as they are in regular, light mode. All that whiteness and brightness can be jarring against the dark elements of dark mode.

At launch, third-party apps have yet to adopt the dark mode UI but many should soon now that Mojave is out. Chrome's translucent title bar, however, looks darker against a dark background. 

Dark to light

I haven't found a shortcut for toggling between light and dark modes, but it's not too difficult to locate it in System Preferences. Just go to System Preferences > General and you'll see the Light and Dark options at the top for Appearance.

Dark mode with Dynamic desktop

With Mojave, Apple has introduced a dynamic wallpaper that slowly changes its lighting throughout the day, going from a bright, sunny desert scene during the day and transitioning to a cool, dark screen at night. You can find it by going to System Preferences > Desktop & Screen Saver. 

If you have the dynamic wallpaper selected, your wallpaper will change from the daylight scene to the nighttime scene when you enable dark mode (and vice versa). Without the dynamic wallpaper selected, your wallpaper stays the same when you jump in and out of dark mode, lessening its impact.

Originally published on June 27, 2018. 
Update, Sept. 24: Added information about final release of MacOS Mojave.

For more, here's everything you need to know about MacOS Mojave.