Turning on Dark Mode on Mac is a user interface change to allows both the menu bar and the OS X Dock to be shown as black backgrounds with white text or icons overlaid on top. You can see a higher contrast on menu bar and dock as the result, it makes the menu bar and dock looks more interesting than the default.
Activating the Dark Mode is really easy in OS X, and it will directly impact the appeareance of the dock, menu bars, menu bar items, and menu bar dropdowns, so does the appearance of Spotlight on the Mac.
Steps to Enable Dark Menu Bar & Dark Dock Mode in Mac OS X
- Open System Preferences from the Apple menu and go to “General”
- Near the top of the preference pane check the box saying “Use dark menu bar and Dock” to activate Dark Mode
- You’ll see the change in the menu bar at the top of the screen automatically.
- Scroll down a menu bar item shows additional dark mode theming:
And the Dock at the bottom of the screen will show up against a transparent dark background rather than a transparent light gray background:
Disabling Dark Mode in Mac OS X (the Default)
- You can go back to System Preferences from the Apple menu and head to “General”
- Uncheck the box saying “Use dark menu bar and Dock” to disactivate Dark Mode and use the default light menu bar and Dock
- This returns to the default settings of light mode in OS X, as you can see in the menu bar:
Light mode default settings are visible in pull down menus too:
Basically the default light mode offers a much brighter Dock on the Mac.
Most of the users want to keep the setting enabled or disabled, if you like to change it a lot, you can use a keyboard shortcut to toggle Dark Mode off and on at any point from anywhere in OS X too.
The Dark Mode feature is available in OS X 10.10 and later, including OS X El Capitan. Unfortunately this feature only change the appeareance of menu, dock and spotlight but maybe it will expand in future versions to encompass more user interface elements including windows, titlebars, much like exists in the Photos app editing UI.