Наведение на псевдо элемент after

.container {
  width: 200px;
  height: 100px;
  border: 1px solid #333;
  position: relative;
}
.container:after {
  position: absolute;
  content: '';
  width: 100px;
  height: 100px;
  cursor: pointer;
  background: #f48255;
}
.container:hover:after {
  background: #7f2f2f;
}

<div class="container"></div>