Did everything according to the guide. Instead of redirecting to main page, accessing my domain (as well as */index.php) displays a page that contents a single "+" symbol and debug outputs if switched on, and nothing else.
Also, CSS broke after fiddling with short urls, now even if I undo everything I still have this error:
Refused to apply style from... because its MIME type ('text/html') is not a supported stylesheet MIME type, and strict MIME checking is enabled.
Not asking for help, but the guide probably needs to be updated.