css - How to layer box-shadows using z-index?

Question

codepen

#b {
  background: orange;
  box-shadow: 0 0 10px black;
  z-index: 2;
  position: relative;
}

#c {
  background: red;
  z-index: 1;
  position: relative;
}

ul {
  list-style: none;
  margin: 0;
  padding: 0;
  z-index: 1;
  position: relative;
}

li {
  display: inline-block;
  padding: 2px 5px;
}

.current {
  background-color: orange;
  z-index: 3;
  position: relative;
}

#d {
  box-shadow: 0 0 10px black;
  z-index: 2;
}

<div id="a">
  <div id="b">bbb</div>
  <div id="c">
    <ul>
      <li>a</li>
      <li class="current">b</li>
      <li>c</li>
      <li>d</li>
    </ul>
  </div>
</div>
<div id="d">dddd
</div>

Answer 1

If you're using z-index, make sure the element has a defined position attribute or it won't work. Wherever you use z-index in your css, define the position of that element. (Absolute, relative, inherit...)