The z-index CSS property sets the z-order of a positioned element and its descendants or flex items. Overlapping elements with a larger z-index cover those with a smaller one.

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For a positioned box (that is, one with any position other than static), the z-index property specifies:

  1. The stack level of the box in the current stacking context.
  2. Whether the box establishes a local stacking context.


/* Keyword value */
z-index: auto;

/* <integer> values */
z-index: 0;
z-index: 3;
z-index: 289;
z-index: -1; /* Negative values to lower the priority */

/* Global values */
z-index: inherit;
z-index: initial;
z-index: revert;
z-index: revert-layer;
z-index: unset;

The z-index property is specified as either the keyword auto or an <integer>.



The box does not establish a new local stacking context. The stack level of the generated box in the current stacking context is 0.


This <integer> is the stack level of the generated box in the current stacking context. The box also establishes a local stacking context. This means that the z-indexes of descendants are not compared to the z-indexes of elements outside this element.

Formal definition

Initial value auto
Applies to positioned elements
Inherited no
Computed value as specified
Animation type an integer
Creates stacking context yes

Formal syntax

z-index = 
auto |
<integer> |


Visually layering elements


<div class="wrapper">
  <div class="dashed-box">Dashed box</div>
  <div class="gold-box">Gold box</div>
  <div class="green-box">Green box</div>


.wrapper {
  position: relative;

.dashed-box {
  position: relative;
  z-index: 1;
  border: dashed;
  height: 8em;
  margin-bottom: 1em;
  margin-top: 2em;
.gold-box {
  position: absolute;
  z-index: 3; /* put .gold-box above .green-box and .dashed-box */
  background: gold;
  width: 80%;
  left: 60px;
  top: 3em;
.green-box {
  position: absolute;
  z-index: 2; /* put .green-box above .dashed-box */
  background: lightgreen;
  width: 20%;
  left: 65%;
  top: -25px;
  height: 7em;
  opacity: 0.9;



Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
z-index 1 12 1 4 4 1 ≤37 18 4 14 1 1.0
negative_values 1 12 3 4 4 1 ≤37 18 4 14 1 1.0

See also

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