<!DOCTYPE html>
<html>
<head>
  <meta charset="utf-8">
  <title>CSS Reftest Reference</title>
  <link rel="author" title="Daniel Holbert" href="mailto:dholbert@mozilla.com">
  <style>
    .abspos-box {
      position: absolute;
      width: 200px;
      height: 200px;
    }

    /* The boxes should stack in the order that I've listed their CSS classes
       here.  The class names' first word (outside/before/inside/after) refers
       to the boxes' DOM position, and "background"/"midground"/"foreground"
       refers to their z-index values. */

    .before-IB-background {
      background: darkmagenta;
      z-index: -1;
      top: 50px;
      left: 50px;
    }
    .after-IB-background {
      background: magenta;
      z-index: -1;
      top: 70px;
      left: 70px;
    }
    .outside-span-midground {
      background: darkkhaki;
      top: 90px;
      left: 90px;
    }
    .inside-IB-midground {
      background: khaki;
      top: 110px;
      left: 110px;
    }
    .before-IB-foreground {
      background: darkcyan;
      z-index: 1;
      top: 130px;
      left: 130px;
    }
    .after-IB-foreground {
      background: cyan;
      z-index: 1;
      top: 150px;
      left: 150px;
    }
  </style>
</head>
<body>
  <!-- The expectation here is that 'abspos-box' elements will all interact in
       the same top-level stacking context. That means the box ordering should
       be (back to front): darkmagenta/magenta/darkkhaki/khaki/darkcyan/cyan,
       with the boxes stacked (visually) from top-left to bottom-right. -->

  <div class="abspos-box outside-span-midground"></div>

  <!-- Note: this file is identical to the testcase,
       except for the lack of "contain: layout" on this span. -->
  <span>
    <div class="abspos-box before-IB-background"></div>
    <div class="abspos-box before-IB-foreground"></div>
    <!-- This unstyled div crates the IB split: -->
    <div>
      <div class="abspos-box inside-IB-midground"></div>
    </div>
    <div class="abspos-box after-IB-background"></div>
    <div class="abspos-box after-IB-foreground"></div>
  </span>
</body>
</html>