<!doctype html>
<meta charset="utf8">
<title>CSS Content Visibility: dialog shows when rendered (ref)</title>

<style>
.box { width: 100px; height: 100px; border: 1px solid black; }
</style>

<div id=container class=box>
content
<dialog id=dialog>dialog<div id=inner></div></dialog>
</div>
text

<script>
dialog.showModal();
</script>