Chanukah starts during the last days of the winter lunar Jewish month of Kislev. Days are short and the sky grows darker, as less of the moon can be seen. Simultaneously we light more and more candles, but according to Jewish Law, it is forbidden to use the light of the candles. They are only to "publicize the miracle" of Chanukah.
What's the miracle?
What is the true miracle? Is it really about some oil?
In the earliest of the writings about the history of the time and about the holiday of Chanukah, nothing was said about oil.
The true miracle was that there were Jews willing to fight, even as the situation got darker. Yes, just like the sky gets darker during Chanuka. We light more and more oil/candles, but we can't use the light.
The suddenly, the moon shows some light. It's Rosh Chodesh Tevet. Gd brings back the light, because we fought for Jewish Rights, Jewish Religion. We were smaller and weaker, but when we fought the Greeks, our enemies, then Gd joined us and suddenly we were strong. We won! Yes, a miracle: