<!DOCTYPE html>
<html>
  <head>
    <title>Identical style declaration on elements with different writing modes</title>
  </head>
  <body style="overflow:hidden;">
    <p>There should be no red on this page.</p>
    <div style="block-size:10px;"></div> <!-- set height -->
    <div style="-webkit-writing-mode:vertical-lr; width:100px; height:100px; background:red;">
      <div style="block-size:10px;"> <!-- set width! -->
        <div style="width:100px; background:white;"></div>
      </div>
    </div>
  </body>
</html>