<!DOCTYPE html>
<meta name="viewport" content="width=device-width,initial-scale=2">
<!--
  This content height is 50% of the window height but it's scaled by 2x so that
  there should be scrollbars.
  -->
<style>
html, body {
  margin: 0;
  width: 100%;
  height: 50%;
}
div {
  background: green;
  position: absolute;
  width: 100%;
  height: 50%;
}
</style>
<div></div>