{# One notification. Assertive, because it reports something that already
   happened and the reader may have moved focus on. #}
<div class="toast toast--{{ flash.kind }}" role="status" aria-live="polite">
  <span class="toast-text">{{ flash.message }}</span>
  <button class="toast-close" type="button" aria-label="Dismiss"
          onclick="this.closest('.toast').remove()">×</button>
</div>