[keycloak-user] Changing login form in OIDC Authorization Code Flow

Hi, I'm trying to use OpenID Connect interface provided by Keycloak and I've got one doubt: is there any way to customize the login form returned by Keycloak to /protocol/openid-connect/auth request in Authorization Code Flow? By customizing I mean not only changing the page itself, but also the way the form is processed, e.g. it would call external service and after successful authentication, user would be redirected to redirect_uri with code granted (assuming session in Keycloak was created somehow in the meantime). If there isn't as I guess, would it be acceptable to implement such a feature and merge it? I suppose it would be compliant with OpenID Connect Authorization Code Flow. -- Pozdrawiam, Daniel Radzikowski. ​​