<style>
  div::-webkit-scrollbar {
    width: 50%;
    height: 20%;
    background-color: green;
  }

  div {
    font-family: Ahem; 
    width: 200px;
    height: 100px;
    overflow: scroll;
    color: white;
}
</style>
<div>PASS if the vertical scrollbar width/height computes to the default scrollbar width...and some more text here.</div>