Not really heard afraid of the dark but my doe every time it became dark and everyone went to bed. She started to throw around her litter box while stomping the floor.
I think she didn’t like how quiet it became during the night. Now she live outdoors with a lamp always on during the night. She can listen to the wind and different animals moving around, so she have calmed down
Mine do get skittish and on high alert when it's getting dark, catching an escaped rabbit in the wood after nightfall is quite a feat, even if it's one you just can walk up to and pick it up in daylight, or even comes for a treat normally. Doesn't work when it's getting dark, they get awfully paranoid then, well, understandable, therre's a lot of claws and teeth out there.
When they are in the house or hutch they are relaxed, I need a flashlight when I step out of bed in the night to not stumble over flopped, sleeping, blissfully-ignoring-me bunnys. If there is something they hear though, like a mouse that sneaked in, I get a STOMP! concert in the middle of the night.
Other rabbits seem to stomp just because of a bad dream.
Rabbits can see very well in low light situations, but they cannot see well in pitch black darkness.
For environments where there is very little or no light during the night, something like a nightlight is very helpful to allow rabbits to see better (and therefore feel a bit safer being able to see their environment).