<!DOCTYPE html>
<style>
  :focus-within {
    column-width: 1px;
    width: 0;
  }
  :nth-last-child(3) {
    margin-block-end: 1px;
    float: right;
  }
  :nth-last-child(3)::first-letter {
    background: grey;
  }
</style>
<script>
  if (window.testRunner)
    testRunner.dumpAsText();
  
  onload = () => {
    document.body.appendChild(document.createElement('span'));
    document.body.appendChild(document.createElement('div'));
    document.body.appendChild(document.createElement('span'));
    document.designMode = 'on';
    document.execCommand('SelectAll');
    document.body.appendChild(document.createElement('div'));
  };
</script>
<body>
</body>