12 Adar (purim)

Yoma 29a-Esther is compared to the dawn because dawn is end of night so too Esther is the end of nissim. That means that the time of miracles is compared to night and the time of no miracles is like the dawn? Why is the time of miracles night, that should be the light in the mashal and Esther should be the nightfall? Light should seemingly be the open giluy of Hashem!