<!DOCTYPE HTML>
<title> Ensure left doesn't take effect if margin isn't auto </title>
<link rel="help" href="https://github.com/w3c/csswg-drafts/issues/3973">
<link rel="match" href="div-orthogonal-left-and-non-auto-margin-ref.html">
<style>
#outer {
inset: 0;
writing-mode: vertical-rl;
background-color: black;
margin: auto;
left: 10px;
margin-right: 10px;
position: absolute;
block-size: max-content;
inline-size: 100px;
border: 5px solid red;
}
</style>
<div id="outer"><div style="block-size: 200px;"></div></div>