Yes, feminism permits women to work late at nights. The problem feminism has with women working late is that often a man working the same hours will get paid more than the woman doing the same job as the man. Feminism does not dictate when a woman can and cannot work. Feminism seeks to allow women the same political, social, and economic freedoms as men.
It also advocates that women, whenever they are working, not be discriminated against, harassed, or treated unfairly in the workplace. This includes not being overlooked for promotions or being asked to provide sexual favors in order to prevent being fired or demoted.