Huddle landing page with single introductory section

Hi. I've some questions about the best way to code. I've done the challenge, but I feel like I'm not doing in the best way. For example: the reset in "*" and "body":

I used this, and worked:

• { margin: 0; padding: 0; box-sizing: border-box; }

In the body I put this: height: 100vh;

Worked, but is the better way to do this?

Other question is about centralize the content. In all my projects I put the content box in position absolute, but when we change to mobile version I needed to change a lot of things. In this challenge I just needed to change "top", but I was in doubt if was the better way to do.

Please give me your feedback, it'll help a lot. Thank! :)