Fade in and out

I want to fade page loading with CSS animation, does anyone know how to do that? I really like the animation that Vertech uses in build-a-thon 2021 to show what resources are included in their package. I have downloaded the resources from Ignition Exchange and I think I found the class “magictime vanishIn”. I have tried to add the class to my page, but nothing happens …
I’m new to css, but if any helpful soul want to answer, I’m grateful

Think I solved it myself, just needed to put 0 on opacity. Absolutely wonderful animation

Do remember that the end user might hate unneccesary animation that are useless for the operation and usabillity of a machine/function.