 dashed seagreen;
        padding: 4px;
      }

      .slotContainer ::slotted(.add1) {
        box-sizing: border-box;
        height: 20px;
        background: lightgray;
        border: 2px solid yellow;
      }
    </style>
    <x-attach2><div class="slotContainer"><slot></slot><div></x-attach2>
  </template>
  <script type="module">
import '../../polymer-legacy.js';
import { Polymer } from '../../lib/legacy/polymer-fn.js';
Polymer({
  is: 'x-attach1',
  attached: function() {
    var d = document.crea