gatein.ear/02portal.war/login/jsp/login.jsp
A portal visual identity is made of HTML produced as a result of portal aggregation (the components that make a page like columns and rows combined with the content produced by the portlets) and associated CSS files.
EPP allows to deploy multiple skins consisting of CSS files, which makes it possible to apply styling to the page compositions and components of a page (portlets). Different skins can be applied to the different websites, also if made available to the users, they can choose their preferred skin.
When accessing a page that requires privileges, a login page is shown and it can be customized by using an extension. To do so, it would be enough to copy the file located at:
gatein.ear/02portal.war/login/jsp/login.jsp
and include it in a portal extension such as myExtension.ear/myWar.war/login/jsp/login.jsp
All the logic must be carefully kept in the login page so that the portal will keep working as it should.
To modify the modal window which pops up when the user decides to sign-in, the extension would have a modified copy of:
gatein.ear/02portal.war/groovy/portal/webui/UILoginForm.gtmpl