accordion.html

  <ngb-accordion #acc="ngbAccordion" activeIds="ngb-panel-0">
    <ngb-panel title="Simple">
     <ng-template ngbPanelContent>
       Sample content
     </ng-template>
    </ngb-panel>
    <ngb-panel>
     <ng-template ngbPanelTitle>
       <span>&#9733; <b>Fancy</b> title &#9733;</span>
     </ng-template>
     <ng-template ngbPanelContent>
       Sample content
     </ng-template>
    </ngb-panel>
    <ngb-panel title="Disabled" [disabled]="true">
     <ng-template ngbPanelContent>
       Sample content
     </ng-template>
    </ngb-panel>
  </ngb-accordion>