Is looking in the mirror at night prohibited, and if so, what is the wisdom behind that?

There is no religious text that prohibits or discourages looking in a mirror at night. However, some physicians have disliked it. Ibn al-Qayyim, in Zad al-Ma'ad, quoted Ibn Masawayh as saying: "Whoever looks in a mirror at night and is afflicted with epilepsy or a disease, let him blame no one but himself." He did not mention a reason for this. Since the matter is purely medical, one should consult medical professionals regarding it.