How to Locate and Customize the OAuth Implicit Flow Redirect Screen?

I am working on a project where an Angular app uses OAuth with an implicit flow. I need to find and possibly customize the screen displayed after the implicit flow redirects. The configuration is set up like this:

"LoginConfiguration": {
      //some parameters set here
    },
authCodeFlowConfig = AppConfig.LoginConfiguration;
oauthService.configure(this.authCodeFlowConfig);
oauthService.initImplicitFlow(undefined, credentials);

Questions:

1. Finding the Screen:

   • How do I locate the HTML or code for the screen shown after the implicit flow? If it's provided by an external OAuth provider, is there any way to customize it?

2. Disabling Button:

   • How can I disable the login button if either the username or password fields are empty?

The implicit flow triggers a redirect to a page with a login form, which I need to customize or interact with. The backend call send from the login screen is handled in the backend, that I can easily debug, but I need to customize the screen on the frontend.

Thanks for your help!

There is a Razor Markup (cshtml) file in the backend of my project, which I can customize.