<div id="div1">
  <h2>div #1</h2>
  <code>position: relative;<br/>z-index: 5;</code>
</div>
<div id="div2">
  <h2>div #2</h2>
  <code>position: relative;<br/>z-index: 2;</code>
</div>
<div id="div3">
  <div id="div4">
    <h2>div #4</h2>
    <code>position: relative;<br/>z-index: 6;</code>
  </div>
  <h2>div #3</h2>
  <code>position: absolute;<br/>z-index: 4;</code>
  <div id="div5">
    <h2>div #5</h2>
    <code>position: relative;<br/>z-index: 1;</code>
  </div>
  <div id="div6">
    <h2>div #6</h2>
    <code>position: absolute;<br/>z-index: 3;</code>
  </div>
</div>
* { margin: 0; }
html { padding: 20px; }
div {
  position: relative;
  opacity: 0.7;
}
#div1,
#div2 {
  background-color: #cfc;
  padding: 10px;
  border: 1px dashed #696;
}
#div1 {
  width: 160px;
  height: 280px;
  margin-bottom: -220px;
  left: 300px;
  z-index: 5;
}
#div2 {
  width: 500px;
  padding-top: 240px;
  z-index: 2;
}
#div3 {
  background-color: #fdd;
  padding: 40px 20px 20px;
  border: 1px dashed #900;
  position: absolute;
  top: 40px;
  left: 100px;
  width: 340px;
  z-index: 4;
  opacity: 1;
}
#div4,
#div5 {
  background-color: #ffc;
  border: 1px dashed #996;
}
#div4 {
  padding: 25px 10px 5px;
  margin-bottom: 15px;
  z-index: 6;
}
#div5 {
  padding: 5px 10px;
  margin-top: 15px;
  z-index: 1;
}
#div6 {
  width: 180px;
  background-color: #ddf;
  padding: 300px 20px 20px;
  border: 1px dashed #009;
  position: absolute;
  top: 20px;
  left: 200px;
  z-index: 3;
}

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