Please, can you change color for input/output?

The output should be green and the input red. You can add a flag in the settings to change it (so as not to break the current user experience).

It would be helpful if you explained your use case. Why do you want the colors swapped?

Not the OP, but Emergency Exits plates are always green, so my mind also associate green with exit.

In my culture the exit is always green, but in this wonderful game I constantly confuse the entrance and exit and I have to constantly flip buildings and I can't get used to it.

The red is terrible for my colour vision, so I'd rather they just be configurable. There's a reason other games (and Portal) use orange and blue.