Trouble adding social media buttons on header

I’m kinda new at this, and I had an extensive look at how I can solve this issue, but none of the fixes are working for me.

My site: https://annatorv.org/test
I’m trying to get the social media icons over the header (in the area where the picture of the icons are), but they either lie behind the header, or push the rest of the page down.

Here is my CSS for the header:
[CSS moderated as per the Forum Rules. Please just post a link to your site.]

And the html (I tried moving the code for the icons before the <header>, after it, and in the <nav> part, and nothing works):
[Code moderated as per the Forum Rules. Please use the pastebin]

Help! And thanks in advance!