<!DOCTYPE html>
<head>
<title>contain: strict element with subgrid properties</title>
<link rel="author" title="Mozilla" href="https://mozilla.org">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1606485">
</head>
<style>

#gridcontainer {
  display: grid;
  contain: strict;
}

.item {
  display: grid;
  grid: subgrid [x] / subgrid [x];
}
</style>
<div id="gridcontainer">
<div class="item">Text1</div>
</div>
