I am painting my dining room and there arches at each entrance.

What color do I paint the arches?

The kitchen is darker green and the dining room will be beige (it is currently off-white). Do I paint the arch beige or leave a stip of off white?

At the other entrance to the dining room, the living room is off-white and I will leave it that way. Do I paint the arch the color of the dining room (beige) or do I leave it off-white to match the living room?