<!DOCTYPE html>
<style>
  video {
    block-size: 400px;
  }
  input {
    float: left;
    content: url();
  }
</style>
<script>
  onload = () => {
    document.documentElement.prepend(document.createElement('span'));
    document.body.append(document.createElement('div'));
    document.body.append(document.createElement('span'));
    document.documentElement.append(document.createElement('div'));
    let html2 = document.createElement('html');
    html2.style.blockSize = '0';
    document.body.appendChild(html2);
    html2.appendChild(document.createElement('q'));
    html2.appendChild(document.createElement('input'));
    html2.appendChild(document.createElement('video'));
    document.body.offsetTop;
    document.styleSheets[0].insertRule(`html, body, video { float: left; }`);
    if (window.testRunner)
        testRunner.dumpAsText();
  };
</script>
PASS if this doesn't crash