<!DOCTYPE html>
<html lang="en">
<meta charset="utf-8">
<title>Scrollboxes with uniform backgrounds should pull that color into their contents, even through an opacity container layer</title>

<style>

div {
  min-height: 50px;
  box-model: border-box;
}

.first, .second {
  border: 1px solid blue;
  margin: 50px 0;
}

.border {
  border: 1px solid black;
}

.scrollable {
  height: 150px;
  overflow: auto;
}

.scrollarea {
  width: 5000px;
  border: none;
  padding: 10px 0 20px;
  height: auto;
}

.scrolled {
  margin-left: 220px;
  width: 100px;
  height: 100px;
  border-color: red;
}

.opacity {
  opacity: 0.9;
}

body {
  margin: 0;
  padding: 0 100px;
  height: 3000px;
}

</style>

<div class="first" reftest-assigned-layer="page-background">
  <!--
    This is just a regular box, it should end up in the page background layer.
  -->
</div>

<div class="opacity border">
  <div class="opacity scrollable">
    <div class="scrollarea">
      <div class="scrolled border reftest-opaque-layer">
        <!--
          The background of .scrollable is uniform and opaque,
          .scrolled should be able to pull up that background color and become
          opaque itself.
        -->
      </div>
    </div>
  </div>
</div>

<div class="second" reftest-assigned-layer="page-background">
  <!--
    This should share a layer with .first and the page background.
  -->
</div>

<script>

var scrollable = document.querySelector(".scrollable");

// Make .scrollable start out with active scrolling.
scrollable.scrollLeft = 0;
scrollable.scrollLeft = 20;

</script>