Угловой липкий нижний колонтитул

<!--index.html-->
 <!-- Full height body -->
    <body class="pt-3 h-100">
<!-- Full height app container, and also use flexbox columns -->
      <app-root class="d-flex flex-column h-100"></app-root>
    </body>
    
 <!--app.component.html-->
 <router-outlet></router-outlet>
<!-- Footer top margin must be set on auto -->
<app-footer class="mt-auto"></app-footer>
Louis Bonnet