z-index not working on side nav

Question

I am trying to have the hamburger menu "on top" of the side nav, to later toggle the sidenav with this hamburger (instead of having to close it with the x).

Problem is that the z-index seems to be ignored. Why is that and how can I resolve that to bring the hamburger to the front even when the sidenav comes in?

function openNav() {
    document.getElementById("myNav").style.width = "100%";
}

function closeNav() {
    document.getElementById("myNav").style.width = "0%";
}

.overlay {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: blue;
    overflow-x: hidden;
    transition: 0.5s;
}

.overlay-content {
    position: relative;
    top: 25%;
    width: 100%;
    text-align: center;
    margin-top: 30px;
}

.overlay a {
    padding: 8px;
    text-decoration: none;
    font-size: 36px;
    color: #818181;
    display: block;
    transition: 0.3s;
}

.overlay a:hover, .overlay a:focus {
    color: #f1f1f1;
}

.overlay .closebtn {
    position: absolute;
    top: 20px;
    right: 45px;
    font-size: 60px;
}

.front {
    z-index: 1050;
}

<div id="myNav" class="overlay">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <div class="overlay-content">
    <a href="#">About</a>
    <a href="#">Services</a>
    <a href="#">Clients</a>
    <a href="#">Contact</a>
  </div>
</div>

<h2>Fullscreen Overlay Nav Example</h2>
<span class="front" style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>

Answer 1

Please check the .front's position property. position: static;, position: initial; ignore z-index.

If you want to give z-index without changing position, change to position: relative;

function openNav() {
    document.getElementById("myNav").style.width = "100%";
}

function closeNav() {
    document.getElementById("myNav").style.width = "0%";
}

.overlay {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: blue;
    overflow-x: hidden;
    transition: 0.5s;
}

.overlay-content {
    position: relative;
    top: 25%;
    width: 100%;
    text-align: center;
    margin-top: 30px;
}

.overlay a {
    padding: 8px;
    text-decoration: none;
    font-size: 36px;
    color: #818181;
    display: block;
    transition: 0.3s;
}

.overlay a:hover, .overlay a:focus {
    color: #f1f1f1;
}

.overlay .closebtn {
    position: absolute;
    top: 20px;
    right: 45px;
    font-size: 60px;
}

.front {
    position: absolute;
    z-index: 1050;
}

<div id="myNav" class="overlay">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <div class="overlay-content">
    <a href="#">About</a>
    <a href="#">Services</a>
    <a href="#">Clients</a>
    <a href="#">Contact</a>
  </div>
</div>

<h2>Fullscreen Overlay Nav Example</h2>
<span class="front" style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>

Answer 2

Z-index only only works for positioned elements and that too only inside its own stacking context. <span class="front" ...">&#9776; open</span> is not positioned. You can read this article to learn more. Possible duplicate: Why does z-index not work?.

Answer 3

Add front class to your h2 element and add position: relative to front style:

function openNav() {
    document.getElementById("myNav").style.width = "100%";
}

function closeNav() {
    document.getElementById("myNav").style.width = "0%";
}

.overlay {
    height: 100%;
    width: 0;
    position: fixed;
    z-index: 1;
    top: 0;
    left: 0;
    background-color: blue;
    overflow-x: hidden;
    transition: 0.5s;
}

.overlay-content {
    position: relative;
    top: 25%;
    width: 100%;
    text-align: center;
    margin-top: 30px;
}

.overlay a {
    padding: 8px;
    text-decoration: none;
    font-size: 36px;
    color: #818181;
    display: block;
    transition: 0.3s;
}

.overlay a:hover, .overlay a:focus {
    color: #f1f1f1;
}

.overlay .closebtn {
    position: absolute;
    top: 20px;
    right: 45px;
    font-size: 60px;
}

.front {
    z-index: 1050;
    position: relative;
}

<div id="myNav" class="overlay">
  <a href="javascript:void(0)" class="closebtn" onclick="closeNav()">&times;</a>
  <div class="overlay-content">
    <a href="#">About</a>
    <a href="#">Services</a>
    <a href="#">Clients</a>
    <a href="#">Contact</a>
  </div>
</div>

<h2 class="front">Fullscreen Overlay Nav Example</h2>
<span class="front" style="font-size:30px;cursor:pointer" onclick="openNav()">&#9776; open</span>