src/app/dialogs/alert/alert.component.html

<header>
  <h2>
    Benachrichtigung
  </h2>
</header>

<div class="panel panel-default alert-dialog">
  <div class="panel-body">
    <span>{{ alertMessage }}</span>
  </div>
</div>

<div class="margin-top">
  <button class="btn btn-primary btn-sm" (click)="dialogRef.close()">OK</button>
</div>