Dark mode only works on menu bar but not for windows and apps
I'm using MacBook Pro (13-inch, 2018, Four Thunderbolt 3 Ports) and running Big Sur.
I selected Dark Mode in system preferences but only the menu bar turned dark.
Finder windows, Safari, etc remained unchanged (i.e light mode).
What could be the problem?
MacBook Pro 13″, macOS 10.14