Can someone explain me these css units?

I’ve finished the “Registration form” lesson, but I didn’t understand some things about the CSS part.
I didn’t understand rem, em and vh, can someone explain them to me?

PS: I also need help with vertical-align if possible.

edit: I understood something about rem by checking the forum, but I’m still not sure if I got it right.

Hi! To understand units better I recommend this article:

And this for vertical-align:

Hope it helps :slightly_smiling_face:


Just read the articles, and I think I understand now.

Thanks for helping me out.