forty Thanks for providing the additional details.
With a Single Article menu item, the page should inherit the layout assigned to that specific article. In your case, the article is set to use the detail-doctor layout.
I just tested the same setup, and it's working as expected.
Menu item:

Article:

Frontend:

P.S. I tried accessing the backend of your website to investigate further, but the HTTP authentication credentials (username: markou) don't seem to work. Could you please verify them and send the updated credentials if needed?