title: How to override CSS of ngbPopover in angular 5?
body: <p>I'm using ng-bootstrap and want to add custom CSS for popover content.
  I'm trying to apply in app.component.css but it is not applying in popover-body.</p>
  
  <p><a href="https://i.stack.imgur.com/GuQzX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/GuQzX.png" alt="Check this!! I want to apply CSS in this attribute"></a></p>