小编car*_*ary的帖子

#twitter{
  width:50px;
  height:50px;
  position: absolute;
  right: 0%;
  bottom: 0%;
  background-color: orange; 
  z-index:-2;
}

#socialButton {
  position: relative;
  width: 80px;
  height: 80px;
  background-color: green;
  z-index: 2;
}

#socialButtonRoot {
  width: 100px;
  height: 100px;
  top:20%;
  left:20%;
  position: absolute;
  background-color: hotpink;
  z-index: 5;
}

<div id="socialButtonRoot">
  <div id="socialButton">
    <div id="twitter"></div>
  </div>
</div>