Implementing a log-in screen in my Angular app has presented me with the challenge of hiding the main navigation bar while the log-in screen is active. Once the user successfully logs in, I need to display the main nav again. Currently, the main nav is part of the Index.html file, which is the first file served and also where ng-app is defined. I am aware that I can use the ng-show attribute, but I'm unsure how to specify the condition for ng-show that can be accessed and modified from different parts of my single-page application. Any guidance or examples using $rootScope or similar solutions would be greatly appreciated.