 {
    width: 50px;
    height: 50px;
    background: black;
  }

  .inner {
    position: relative;
    top: -10px;
    left: -10px;
    height: 100px;
    width: 100px;
    background: blue;
    opacity: 0.5;
  }
</style>
<!-- there should be no scrollbars -->
<div class="wrapper" style="overflow: auto">
<div class="outer" style="overflow:clip; outline:solid red">
  <div class="inner"></div>
</div>
</div>

<!-- there should be no white areas inside the outline -->
<div class="wrapper" style="outline: soli