<!DOCTYPE html>
<title>Default namespace respected inside :is() for non-subject compounds</title>
<link rel="help" href="https://drafts.csswg.org/selectors-4/#matches">
<link rel="match" href="/css/reference/blank.html">
<!--
  Default namespace declarations do not affect the compound selector
  representing the *subject* of any selector within a :is() pseudo-class, unless
  that compound selector contains an explicit universal selector or type
  selector.
-->
<style>
@namespace "http://www.w3.org/1999/xhtml";

*|*.a {
  display:none;
}

/* This should not apply, since the '.container' compound is affected by the
   default namespace (even though the '.a' compound is not). */
*|*:is(.container .a) {
  display:initial;
}

</style>
<svg xmlns="http://www.w3.org/2000/svg" width="200" height="100">
  <g class=container>
    <text class="a" y="1em">FAIL if this text is visible</text>
  </g>
</svg>