Bootstrap 4-beta navbar-inverse和navbar-fixed-bottom无效

I'm trying to set a navbar and a footer using Bootstrap 4-beta in ASP.NETCore web application but the navbar of Bootstrap not working properly I used navbar-inverse and navbar-dark but problem is same and I also trying set a footer using navbar and navbar-fixed-bottom but the footer not going bottom of the page. I'm new to Bootstrap and ASP.NET MVC.I'm trying to set a navbar and a footer using B