viewport-units-in-vertical.html | Explore in Territory

<!DOCTYPE html>
<script>
if (window.testRunner)
    testRunner.setPrinting();
</script>
<style>
html {
  writing-mode: vertical-rl;
}
</style>
<div style="width:50vw; height:50vh; border:2px solid black;"></div>

chromium/third_party/blink/web_tests/printing/viewport-units-in-vertical.html