<!DOCTYPE html>
<link rel="help" href="https://drafts.csswg.org/css-inline-3/#baseline-source">
<style>
#target {
  baseline-source: first;
  vertical-align: baseline;
}
</style>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<div id="target"></div>
<script>
test(() => {
  const target = document.getElementById('target');
  assert_equals(getComputedStyle(target).baselineSource, 'auto');
});
</script>
