<div class="first">
  <div class="second"></div>
</div>
<div class="third"></div>

div {
   width: 50px;
   height: 50px;
   position: absolute;
}

.first {
   top: 0;
   background: #08ff23;
   z-index: 1;
   display: contents;
}

.first::after {
   content: '';
   position: inherit;
   z-index: inherit;
   top: inherit;
   width: inherit;
   height: inherit;
   background: inherit;
}

.second {
   top: 20px;
   background: #ce1248;
   z-index: 3;
}

.third {
   top: 40px;
   background: #2235ac;
   z-index: 2;
}