<!DOCTYPE html>
<meta charset="UTF-8">
<title>Absolutely-positioned element in ruby base container</title>
<link rel="author" title="Xidorn Quan" href="https://www.upsuper.org">
<link rel="help" href="https://drafts.csswg.org/css-ruby-1/#formatting-context">
<link rel="match" href="abs-in-ruby-base-ref.html">
<link rel="stylesheet" href="/fonts/ahem.css">
<link rel="stylesheet" href="support/ruby-common.css">
<style>
  .rel { position: relative; }
  .abs { position: absolute; left: 0; top: -1em; }
</style>
<body style="font: 50px/3 Ahem">
X<ruby><rbc class="rel"><rb><span class="abs">X</span></rb></rbc></ruby>