Some Pages shown without CSS

New installation of 8.6.0, everything went fine.
The problem is that many if not most pages are shown without formatting (CSS).
Create Leads shows fine, Show Leads also fine, but Import Leads and the Home Page for example are a mess without CSS.
PHP 8.2
MariaDB 10.5.23
All pre-installation checks showed OK

How do I get every page to show correctly?

Changing the permission of the “legacy” folder recursively from 755 to 775 solved the issue.