<!DOCTYPE HTML>
<!--
     Any copyright is dedicated to the Public Domain.
     http://creativecommons.org/publicdomain/zero/1.0/
-->
<html><head>
  <meta charset="utf-8">
  <title>Reference: margin:auto on grid abs.pos. child</title>
  <link rel="author" title="Mats Palmgren" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1107783">
  <style type="text/css">

div {
  display: block;
  position: relative;
  grid-template-columns: 100px;
  grid-template-rows: 100px;
  width: 100px;
  height: 100px;
  border: 1px solid;
}

span {
  display: block;
  position: absolute;
  background: lime;
  width: 20px;
  height: 20px;
  margin: 5px 7px 11px 13px;
  top:0; left:0; right:0; bottom:0;
}

  </style>
</head>
<body>

<div><span style="margin-left:auto"></span></div>
<div><span style="margin-right:auto"></span></div>
<div><span style="margin-left:auto; margin-right:auto"></span></div>
<div><span style="margin-top:auto"></span></div>
<div><span style="margin-bottom:auto"></span></div>
<div><span style="margin-top:auto; margin-bottom:auto"></span></div>
<div><span style="margin:auto"></span></div>

</body>
</html>