redoc/lib/common/components/Zippy/zippy.html

<div class="zippy zippy-{{type}}" [ng-class]="{'zippy-empty': empty}">
  <div class="zippy-title" (click)="toggle()">
    {{title}}
    <span class="zippy-indicator"> {{ visible ? '&blacktriangledown;' : '&blacktriangleright;' }} </span>
  </div>
  <div class="zippy-content" [ng-class]="{'zippy-hidden': !visible}">
    <ng-content></ng-content>
  </div>
</div>