Need help in css on position

Hi all, i was trying to center the logo on my @media under 672px on the FCC product landing page, i try at all to fix it with all i can found on internet, in english and french site, i didn’t know at all how to fix it, can someone help me ? its probably a newbie problem but i can’t find it! (ty and sorry for my english)
there is a link to my codepen:

You could lose the float in the #header-img styles. It doesn’t really add to anything. It’s also easier to center the image without it.

Then in the media query you can center the image by setting the #header-img display to block and margins to auto.