How to Make the CSS z-index Property Work

Solutions with the CSS position property

The CSS z-index property works with elements that have a non-static position value (i.e., absolute, relative, fixed, or sticky). It also works on direct children of flex and grid containers without requiring a position value.

Let’s see some examples.

Tip

For standard positioning, use relative, absolute, fixed, or sticky. Alternatively, z-index works on direct children of flex and grid containers without needing a position value.

Example of using the z-index property with the "relative" value of the position property:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      div {
        width: 150px;
        height: 150px;
        padding: 15px;
      }
      .one,
      .two,
      .three {
        position: relative;
      }
      .one {
        background: #a7b5aa;
        outline: 2px solid #000;
        top: 100px;
        left: 200px;
        z-index: 10;
      }
      .two {
        background: #4b48db;
        outline: 2px solid #000;
        top: 50px;
        left: 75px;
        z-index: 100;
      }
      .three {
        background: #1ba13f;
        outline: 2px solid #000;
        top: 30px;
        left: 25px;
        z-index: 150;
      }
    </style>
  </head>
  <body>
    <div class="one"></div>
    <div class="two"></div>
    <div class="three"></div>
  </body>
</html>

Try it Yourself »

Result

<div class="demo mb-20 not-prose"> XFI4 </div> XFI5 </div> XFI6 </div> </div>

Example of using the z-index property with the "absolute" value of the position property:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      img {
        position: absolute;
        left: 0;
        top: 20px;
        z-index: -1;
      }
    </style>
  </head>
  <body>
    <h2>Example</h2>
    <img src="/build/images/w3docs-logo-black.png" alt="W3docs logo" width="195" height="45" />
  </body>
</html>

Try it Yourself »

Now, let’s see how these boxes will behave with the "fixed" value.

Example of using the z-index property with the "fixed" value of the position property:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      div {
        width: 150px;
        height: 150px;
        padding: 15px;
      }
      .one,
      .two,
      .three {
        position: fixed;
      }
      .one {
        background: #a7b5aa;
        outline: 2px solid #000;
        top: 100px;
        left: 200px;
        z-index: 10;
      }
      .two {
        background: #4b48db;
        outline: 2px solid #000;
        top: 50px;
        left: 75px;
        z-index: 100;
      }
      .three {
        background: #1ba13f;
        outline: 2px solid #000;
        top: 30px;
        left: 25px;
        z-index: 150;
      }
    </style>
  </head>
  <body>
    <div class="one"></div>
    <div class="two"></div>
    <div class="three"></div>
  </body>
</html>

Try it Yourself »

Example of using the z-index property with the "sticky" value of the position property:

<!DOCTYPE html>
<html>
  <head>
    <title>Title of the document</title>
    <style>
      div {
        width: 150px;
        height: 150px;
        padding: 15px;
      }
      .one,
      .two,
      .three {
        position: sticky;
        top: 0;
      }
      .one {
        background: #a7b5aa;
        outline: 2px solid #000;
        left: 200px;
        z-index: 10;
      }
      .two {
        background: #4b48db;
        outline: 2px solid #000;
        left: 75px;
        z-index: 100;
      }
      .three {
        background: #1ba13f;
        outline: 2px solid #000;
        left: 25px;
        z-index: 150;
      }
    </style>
  </head>
  <body>
    <div class="one"></div>
    <div class="two"></div>
    <div class="three"></div>
  </body>
</html>

Try it Yourself »

When the z-index property is not applied, the browser stacks elements in the following default order:

root element,
non-positioned elements in the order they are specified,
positioned elements in the order they are specified.

Note

z-index only affects stacking within the same stacking context. Elements in different stacking contexts are stacked according to their parent's position in the document flow.