n a typographic letter unit and a subsequent typographic character unit from the [UAX14] CL line breaking class">
<style>
@supports (word-boundary-detection:auto(ja)) {
  .warn { display:none; }
}
div {
  font-size: 2em;
  border: solid black;
  margin: 5px;
  width: 30ch;
}
#test {
  word-boundary-detection: auto(ja);
  word-boundary-expansion: ideographic-space;
}
</style>

<p class=warn><strong>This test is not relevant, because this UA does not support <code>word-boundary-detection:auto(ja)</code>.</str