It must be dark inside, but nobody cares. The shutters prevent the cold wind from entering the building, maintaining a thin layer of warmer air behind the windows.
I don’t know if the japanese prints are still kept hanging on the walls. If they are, darkness is a relief for their fragile colors.
Shut shutters look like closed lids. When it is cold outside, sleeping is the best thing to do, isn’t it?
So do the bulbs hidden in the flower beds and the buds on the branches. Yes, sleeping is the best option before a very long time of intense activity.