<!DOCTYPE html>

 <html lang="en">

  <meta charset="UTF-8">

  <title>CSS Reftest Reference</title>

  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">

  <style>
  div
    {
      font-size: 60px;
      line-height: 1;
    }

  span#outer
    {
      color: transparent;
    }

  span#inner
    {
      background-color: yellow;
    }

  div#overlapping-line
    {
      margin-top: -60px; /* -1lh unfortunately is not implemented */
    }

  div#overlapping-line > span
    {
      background-color: rgba(0%, 50%, 100%, 0.5);
      /*
      a very lite blue color
      according to
      https://www.colorhexa.com/7fbfff
      */
      color: yellow;
    }
  </style>

  <p>PREREQUISITE: User agent needs to have an enabled and capable spelling error module. If it does not, then this test does not apply to such user agent.

  <p>Test passes

  <ul>
    <li>if each glyph of "Txet sample" is yellow
    <li>if "Txet" has a desaturated lime green background
    <li>if " sample" has a very lite blue background and
    <li>if there is no red.
  </ul>

  <!--
  The bad spelling of Txet is intentional and part of this test
  -->

  <div id="overlapped-line"><span id="outer"><span id="inner">Txet</span> sample</span></div>

  <div id="overlapping-line"><span>Txet sample</span></div>