Lord Krishna had dark skin. However, in pop culture, in books, shows, and movies, he is always portrayed as white or is played by a white actor.

There are many and many such misleading and flawed depictions of historical figures and deities in our movies, shows, and books.

(Courtesy: lds.org)

(Because apparently "white" looks better and sells more.)

So, the foremost thing you need to understand is not to take what books and movies tell you at face value… not at least when it comes to something religiously and historically important as Adam and Eve. They are not the right sources. Even when they claim "based on a true story".

Coming to your question, doing whatever search I could do, I did not find anything that suggests Adam and Eve were black. They were not black.

In addition, there isn’t sufficient archeological evidence that suggests old humans are black. Yes, there are clickbait articles on this topic that get published once in a while here and there.But they all lack sufficient data and evidence.

Talking about Adam and Eve, it is believed that they had middle-brown skin color. That's the most natural color of human skin. Following, people started having different skin color because of the varying level of melanin in the body.

(Courtesy: Medium)

This is, of course, a scientific explanation.

Religious theories have a different take to it. These religious people believe that Adam and Eve were white. And so were their off-springs. However, over the course, a few incidents happened that brought people with colored skin to the world. Some believe God cursed a person whose skin then turned black. Others say Noah cursed Canaan, which brought people with colored skin to the world. There are many such theories. It's on you if you want to believe them or not.

But to conclude…

(Courtesy: jw.org)

Neither Adam was white, nor Eve was black. We don’t know the skin color of the earliest humans. There's a lack of sufficient evidence. Different archeologists have different understanding and ideas. There's a good chance that a lot of them will tell you different things on the same topic.

Hope this answer helps!