Is there a easy possibility to change Layout and or Colors/ Logo/ Texts in Backend/ Frontend view?
i.e. the Frontend Site, if some Page is blocked, "Contact Admin...." i would gladely adjust those things, without having them disappear while updating.
You can copy the block page to /var/www/html/pihole/custom.php and modify the CSS path to a copy of the blocking page CSS, then run pihole -r to repair. This will set Pi-hole to use your custom block page.