How Do I Turn On Dark Mode On A Mac?
Dark mode was introduced with macOS Mojave (10.14) and released in the fall of 2018. Macs using older versions of macOS or OS X like High Sierra and Sierra are unfortunately not able to use dark mode but can enable a dark menu bar and dock.
Enabling or disabling dark mode can be done via the Mac System Preferences. Launch System Preferences by clicking on the Apple menu at the top left corner of the screen then select the General panel. Choose the Dark option under the Appearance section to enable dark mode.
Macs with High Sierra and Sierra can switch to a dark menu bar and dock at System Preferences > General > Appearance by checking the option that reads "Use dark menu bar and Dock".