### Is your feature request related to a problem? Please describe. The setup screen is not yet using the new background and icon design. ### Describe the solution you'd like It should be ported to fluid design, similar to https://github.com/nextcloud/mail/pull/11504. ### Describe alternatives you've considered _None_ ### Additional context <img width="1544" height="440" alt="Image" src="https://github.com/user-attachments/assets/ff90b877-3503-4aee-88f6-e48e4c106cfb" />
