Center elements in CSS like a boss

I found that a lot of devs are confused when it comes to center element in CSS. 👀
Here is the trick I always use when starting a web development project.

Here is the gist link : https://gist.github.com/Kolawole39/b39693399dd8851a6e9e95c10a61b70a
And you? How do you proceed? Please feel free to comment.👇