https://mcshelby.github.io/hugo-theme-relearn/pir/introduction/releasenotes/4/0/index.html 4.0.0 (2022-06-05) Break'n Break'n Th' custom_css config parameter was removed from th' configurat'n. If used 'n an exist'n installat'n, it can be achieved by overrid'n th' custom-header.html template 'n a much more generic manner. Hugo art-x-pir