ADVANCED BEHAVIOUR WARNING
I'm putting together a cookbook, which may take a day or two to publish, in the meantime, this is the pattern for dark regions.
Essentially
- Define a 'zone' that contains one or more locations (comma separate locations between the [ ] characters, control + space will work in here.
- Define a dynamic boolean that contains an expression that tests if the protagonist is in the zone, if so return true. This syntax is beyond the scope of "classroom", so I won't explain it too much here.
- In the settings section, reference the name of the boolean that contains the darkness expression.
- (optional) In the system_messagages section. Change your dark message.

EDIT
If you want it to be not dark when something is held, then just add in additional conditions for darkness as such:
