Placed the .vcard css definition in the wrong media definition
Moved the vcard from outside content, to inside
Changed from 'Kontakt' to 'HTML5' for the nav entry to the html5 page
Incorrectly linked to a nonexisting file on index page
Used the online Outline checker to see if my site worked as it should, which it did. Added some extra text to see if it still works as intended
Moved the css to outside of the html file
Forgot to add the new css file