I\'m working with Bootstrap 4 and Ng-Bootstrap in an Angular 4 Project,
i have linked the que bootstrap.css in my angular-cli.json this way
\"styles
Look for the compiled classes, maybe you get the wrong version. I had a similar issue with the class col-sm-offset-#, the problem was that this classes doesn't exist in that version. Maybe could be the same issue
This is the route ..\node_modules\bootstrap\dist\js here we have two file bootstrap.js and bootstrap.min.js
find into bootstrap.js the nav classes. if you could not found it, look for another Bootstrap repository.
Good luck.