pinafore/routes/_components/HiddenFromSSR.html

<!-- toggled in 2xx.html based on whether the user is logged in or not -->
<div class="hidden-from-ssr {{shown ? 'shown' : ''}}">
  <slot></slot>
</div>
<style>
  .hidden-from-ssr {
    opacity: 0;
  }
  .hidden-from-ssr.shown {
    opacity: 1;
  }
</style>
<script>
  export default {
    oncreate () {
      this.set({ shown: true })
    },
    data: () => ({
      shown: false
    })
  }
</script>