portainer/app/kubernetes/components/view-loading/viewLoading.html

<div class="loading-view-area" ng-if="!$ctrl.viewReady">
  <div class="sk-fold sk-center">
    <div class="sk-fold-cube"></div>
    <div class="sk-fold-cube"></div>
    <div class="sk-fold-cube"></div>
    <div class="sk-fold-cube"></div>
  </div>
</div>