Body Top Gap; Should I Use Margin Or Padding?

So, I'm working on a website with a fixed header (which is used to navigate). I use padding-top on body to lower the content to fit with the header. This is how it looks like right

Solution 1:

There's no actual better way to do it. It's just to you. Maybe one will be slightly faster to render then another but nothing that someone could notice.

As a tip anyway is to make the header positioned as fixed so it scrolls down with the user.