<!DOCTYPE html>
<html lang="ja">
<meta charset="UTF-8">
<title>CSS Reference: visibility: collapse hides ruby annotations</title>
<link rel="author" title="Xidorn Quan" href="https://www.upsuper.org">
<style>
  body { line-height: 5; }
  rt { font-size: 80%; }
</style>
<ruby>
  <rb>昆</rb><rb>虫</rb><rb>記</rb>
  <rt>こん</rt><rt>ちゅう</rt><rt>き</rt>
</ruby><br>
<ruby>
  <rb>昆</rb><rb>虫</rb><rb>記</rb>
  <rt>こん</rt><rt style="opacity: 0">ちゅう</rt><rt>き</rt>
</ruby><br>
<ruby>
  <rb>昆</rb><rb>虫</rb><rb>記</rb>
  <rt>こん</rt><rt></rt><rt>き</rt>
</ruby>