paperless-ngx/src-ui/src/app/components/dashboard/widgets/widget-frame/widget-frame.component.html

<div class="card mb-3 shadow">
  <div class="card-header">
    <div class="d-flex justify-content-between align-items-center">
      <h5 class="card-title mb-0">{{title}}</h5>
      <ng-content select ="[header-buttons]"></ng-content>
    </div>
    
  </div>
  <div class="card-body text-dark">
    <ng-content select ="[content]"></ng-content>
  </div>
</div>