Hikari lives with her mother.  No siblings, and obviously dad is not around!  As a Good Girl (TM) she has started taking over most of the domestic matters around the house, like cooking and cleaning.  At midnight she would probably have snuck downstairs to watch TiVo'd anime since she doesn't get to see it during airing hours on account of studying and household chores; so, pink pajamas and cucumber sandwiches in front of a TV with the volume way down in an otherwise dark room.