<!DOCTYPE html>
<link rel=help href="https://drafts.csswg.org/css-writing-modes-4/#block-flow">
<link rel=help href="https://crbug.com/1081659">
<link rel="match" href="writing-mode-initial-ref.html">
<div style="writing-mode:vertical-rl">
  <div style="writing-mode:initial">
    horizontal
  </div>
</div>