<!doctype html>
<title>CSS Color Adjustment Test: Frames with a dark color-scheme should get an opaque background when embedding element and embedded root color-schemes do not match</title>
<link rel="help" href="https://drafts.csswg.org/css-color-adjust/#color-scheme-effect">
<link rel="match" href="support/dark-frame-opaque.html">
<style>
  html, body {
    margin: 0;
    height: 100%;
  }
  iframe {
    margin: 0;
    border: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    display: block;
  }
<