the background of my MacBook Pro is now a neon green. Anyone know why?

Try reset instruction: NVRAM -or- PRAM

Then try detailed: How to reset Mac's SMC

Or just maybe Mac's just a Fan, reveling

Limelight ~ Rush / Spirit Of The Radio 1974-1987

"Living on a lighted stage

Approaches the unreal

For those who think and feel

In touch with some reality

Beyond the gilded cage..."

Take care & good luck!🌻🌤