<div id="container">
  <div id="text">
  </div>
  <div id="float">
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  </div>
</div>

#container{
  background: black;
}

#text{
  min-height: 300px;
  background: #fff;
  border: 1px solid black;
}

#float{
  background: red;
  transform: translatey(-50%);
  min-height: 100px;
  margin: 0 20%;
}