The classic experience for universal login allows you to fully customize it and one of the parameters available within that page is the client identifier, so it’s technically possible to change the layout conditionally per application.
However, the more important question… should you? In general the recommendation would be no, you should not. You should think of this page as the common login page used by the different applications (web site, mobile applications, desktop applications) that your service makes available to your end-users.
What’s the use case you have where multiple applications require a completely different branding?