I need to add color a custom field

Good afternoon community:

I need help to add colors a custom field. I have a field call credit score (Number) and that number changes every month, i want to have this field green when the score went up and red when the score went down.

So if the score is 620 (+10) i want to have the field green and if the score is 610 (-10) i want to have this field red.