Following llagerlof's indications I could make it work with the default password, tested with PHP 7.4.21 and 8.0.8, chmod 755. The meta tags for charset and viewport were merged (?) so I corrected that too, here's the modified file: https://www.pastery.net/zbfwuf/

Great project, thank you. I felt a little stupid when trying to create a new page, then remembered the way of the Wiki and appended ?new-page to the URL, of course. Maybe add this info in the description?