Follow these steps
- System Preferences > General > Appearance: Light
- In Terminal, paste
defaults write -g NSRequiresAquaSystemAppearance -bool Yesand hit
- Go to > Log Out...
- Log back in
- System Preferences > General > Appearance: Dark
- Boom. Dark mode only on the menu bar and dock.
Bonus: Set your desktop background to
#171717 to match the dark menu bar.
If you want to reverse this, I'm assuming you'd just change
defaults write -g NSRequiresAquaSystemAppearance -bool No, but honestly why would you wanna go back?