una/template/layout_1_column.html

<!-- layout 1 column [ start ] -->
<table class="bx-layout-wrapper bx-layout-1-column">
    <tr>
        <td id="bx-layout-cell-1" class="bx-layout-cell bx-layout-1-column-column1"><div>__cell_1__</div></td>
    </tr>
</table>
<!-- layout 1 column [  end  ] -->