css/css-display/display-contents-alignment-002.html

<!DOCTYPE html>
<meta charset="utf-8">
<title>CSS Test: grid container justify-items is used for grid item regardless of intermediate display: contents ancestors</title>
<link rel="author" title="Emilio Cobos Álvarez" href="mailto:ecobos@igalia.com">
<link rel="help" href="https://drafts.csswg.org/css-display-3/#valdef-display-contents">
<link rel="help" href="https://drafts.csswg.org/css-align/#justify-items-property">
<link rel="match" href="display-contents-alignment-002-ref.html">
<style>
  .container {
    display: grid;
    width: 300px;
    height: 300px;
    justify-items: center;
    border: 2px solid purple;
  }
  .contents {
    display: contents;
    justify-items: start;
  }
  .contents > div {
    width: 100px;
    height: 100px;
    background: blue;
    justify-self: auto;
  }
</style>
<p>Test passes if there's a blue square horizontally centered inside the box.</p>
<div class="container">
  <div class="contents">
    <div></div>
  </div>
</div>