<style>
div {
  writing-mode: vertical-lr;
  font-size: 50px;
  font-family: Ahem;
}
span {
  background-color: green;
  color: blue;
}
</style>
<!-- PASS if content and background positions match -->
<div><span>some<span style="vertical-align: 100px">text</span></span>
<div><span style="unicode-bidi: isolate">some<span style="vertical-align: 100px">text</span></span>
