ound: red;
  z-index: -1;
  bottom: 0;
}
.green {
  position: relative;
  background: green;
}
</style>
<div style="height: 800px">Scroll to the bottom. </div>
<div class="clip">
  <div class="fixed"></div>
  <div class="green"></div>
</div>
<script>
onload = () => {
  window.scrollTo(0, 400);
};
</script>
