css/css-text/text-autospace/text-autospace-break-001.html

<!DOCTYPE html>
<meta charset="utf-8">
<link rel="help" href="https://drafts.csswg.org/css-text-4/#text-autospace-property">
<link rel="match" href="text-autospace-break-001-ref.html">
<link rel="stylesheet" type="text/css" href="/fonts/ahem.css">
<style>
.test-container {
  font-family: Ahem;
  font-size: 40px;
  width: 4.1em;
  text-autospace: normal;
}
.test > span {
  outline: 1px solid blue;
}
</style>
<div class="test-container">
  <div class="test"><span>国国国国X国</span></div>
  <div class="test"><span>国国国国1国</span></div>
  <div class="test"><span>XXXX国X</span></div>
  <div class="test"><span>1111国1</span></div>
  <div class="test">国<span>国X国</span></div>
</div>