I'm using Flex but elements still not centering - why?

I want the main elements in both of my projects to be dead center. I have spent all of last night trying to center these. I don’t understand why Flex isn’t working. Help please?

Actually, it is centering, but body doesn’t technically fill the whole height of the window. Unless you tell it otherwise, it will always be the height of its contents.

So… add min-height:100vh; to the body styles and it should lock into place.

Thanks, I didn’t even know about vh/vw until now.