SOURCE

<div class="parent">
  <div class="child">this is child</div>
</div>
<div class="parent2">
  <div class="child2">this is child2</div>
</div>

.parent{
  width: 50px;
  height: 50px;
  background-color: red;
  padding: 2px;
  margin: 2px;
  border: 2px dashed #fff;
  position: relative;
}
.child{
  background-color: blue;
  width: 20px;
  height: 20px;
  position: absolute;
  top: 0;
  left: 0;
  color:#fff;
  text-align:center
}

.parent2{
  width: 50px;
  height: 50px;
  background-color: red;
  padding: 20px;
  margin: 20px;
  border: 2px dashed #fff;
  position: relative;
  box-sizing:border-box;
}
.child2{
  background-color: blue;
  width: 20px;
  height: 20px;
  position: absolute;
  top: 0;
  left: 0;
  color:#fff;
  text-align:center
}