Did dark skin come from god's gift??

I don’t think so, its just evolution’s response to climattc conditions. Skin colour is due to the level of melanin in the skin and it depends on our genes which we inherit from our forefathers. It’s a long drawn process and takes centuries for a particular character of our gene to develop or modify. God has nothing to do with it. Its just our habit of thanking God for everythign we feel is beneficial to us and accusing him for every bad thing that happens to us.

While I am not qualified to answer for your God. I can tell you the evolutionary reasons for different shades of skin color. Its a simple trade off between the need for us to make vitamin D in order to maintain bone strength and the need for women to retain folic acid in order to have healthy babies. When certain rays of sunlight hit your skin your skin makes vitamin D which is absolutely necessary in the process of making and maintaining healthy bones, so you need some sunlight to penetrate the skin in order to make vitamin D. But sunlight rays also cause the deteroation of folic acid in the body. If you don't have sufficient amounts of folic acid and you become pregnant the baby won't be born healthy. Therefore in places that get a lot of sun, like tropical places or places near the equator you need to have protection from the sun in order to keep your folic acid because getting enough sun for vitamin production is not a problem. So you have more melanin in the skin in order to protect yourself. If you live in a more northern climate, where you don't get a lot of sun, you don't have a problem with losing folic acid because you are not getting enough sun for it to cause a problem. But you might have a problem with getting enough sun to make sufficient Vitamin D especially if you have a lot of pigment in the skin blocking sunlight. So people evolve light skin for northern climes in order to obtain sufficient amounts of vitamin D. That is current evolutionary though behind the differences in human skin color.