Cover image for anything that's not home (with fallback to favicon where cover is not set), and for anything that is home we use the favicon with fallback to the default color block
Co-Authored-By: Radek Kozieł <radoslaw.koziel@gmail.com>
Remove Twitter card title, description and image (twitter cards fall back to OG markup for these elements).
Fix og:image url for non-home content
Conditionally show twitter:site tag
Title tags could be a little bloated as the subtitle was being appended. This should fall in to the description instead.
Also, if not looking at an individual post, there was no author being defined or site image.
