="assert" content="The font-metric dependent ch unit on table row groups takes the writing mode (with a sideways text-orientation) into account,
                            even though these properties do not apply to that element.">
<style>
table {
  font-size: 20px;
  border-collapse: collapse;
  border: none;
}
td {
  padding: 0;
  background: green;
  height: 5ch;
}
tbody {
  writing-mode: vertical-rl;
  text-orientation: sideways;
  line-height: 5ch; /* using the inherited line-height (which the affect