<style>
.c1 { display: contents; }
</style>
<script>
function go() {
a.attachShadow({mode: "open"}).innerHTML = `<slot> </slot> `;
b.appendChild(a);
}
</script>
<body onload=go()>
<div id="a" class="c1">
<span></span>
</div>
<svg>
<text id="b">