  body {
      margin: 0;
      padding: 0;
    }
  </style>
</head>
<body>

 <dom-module id="x-grid">
    <template>
      <style include="app-grid-style">

        :host {
          display: block;
          --app-grid-columns: 4;
          --app-grid-gutter: 16px;
          --app-grid-expandible-item-columns: 3;
          --app-grid-item-height: 100px;
          width: 480px;
          background-color: red;

        }

        ul {
          margin: 0;
          padding: 0;
          list-style: none;
 