css/css-masking/clip-path/clip-path-fixed-nested.html

<!doctype html>
<title>CSS Test: nested clip-path() inside the same reference frame with position: fixed</title>
<link rel="author" href="mailto:emilio@crisal.io" title="Emilio Cobos Álvarez">
<link rel="author" href="https://mozilla.org" title="Mozilla">
<link rel="help" href="https://bugzilla.mozilla.org/show_bug.cgi?id=1501111">
<link rel="help" href="https://drafts.fxtf.org/css-masking/#the-clip-path">
<link rel="match" href="clip-path-fixed-nested-ref.html">
<style>
  body, html {
    margin: 0;
    padding: 0;
  }
  .outer-clip {
    height: 100vh;
    clip-path: inset(0 0 0 0);
    background: green;
  }
  .fixed {
    position: fixed;
  }
  .inner-clip {
    height: 50px;
    width: 50px;
    clip-path: inset(0 0 0 0);
  }
  .inner-clip-contents {
    height: 100px;
    width: 100px;
    background: purple;
  }
</style>
<div class="outer-clip">
  <div class="fixed">
    <div class="inner-clip">
      <div class="inner-clip-contents"></div>
    </div>
  </div>
</div>