Bootstrap 6 Z-Index

Example

Use z-index utilities to stack elements on top of one another. Requires a position value other than static, which can be set with custom styles or using our position utilities.

We call these “low-level” z-index utilities because of their default values of -1 through 3, which we use for the layout of overlapping components. The library’s overlay layers are available as utilities too — see Overlays below.

<div class="z-3 position-absolute p-6 rounded-3"><span>z-3</span></div>
<div class="z-2 position-absolute p-6 rounded-3"><span>z-2</span></div>
<div class="z-1 position-absolute p-6 rounded-3"><span>z-1</span></div>
<div class="z-0 position-absolute p-6 rounded-3"><span>z-0</span></div>
<div class="z-n1 position-absolute p-6 rounded-3"><span>z-n1</span></div>

Overlays

CoreUI overlay components—dropdown, modal, offcanvas, popover, toast, and tooltip—all have their own z-index values to ensure a usable experience with competing “layers” of an interface.

Each of those layers has a matching utility, so your own element can join a layer by name instead of repeating the number it happens to have: .z-dropdown / .z-menu, .z-sticky, .z-fixed, .z-sidebar-backdrop, .z-sidebar, .z-offcanvas / .z-drawer, .z-modal / .z-dialog, .z-popover, .z-tooltip and .z-toast. The three pairs share a value: the menu, drawer and dialog are the successors of the dropdown, offcanvas and modal, and sit on the same layer.

<div class="position-relative" style="height: 6rem;">
  <div class="z-modal position-absolute top-0 start-0 p-4 bg-subtle-primary border rounded">Sits at the modal layer</div>
</div>

Read about the values themselves in the z-index layout page.

Customizing

Sass maps

Each entry is one .z-{level} class and the z-index it sets. Add a key to define a level, or set one to null to drop it:

$zindex-levels: () !default;
// stylelint-disable-next-line scss/dollar-variable-default
$zindex-levels: defaults(
  (
    n1: -1,
    0: 0,
    1: 1,
    2: 2,
    3: 3,
    dropdown: 1000,
    menu: 1000,
    sticky: 1020,
    fixed: 1030,
    sidebar-backdrop: 1034,
    sidebar: 1035,
    offcanvas: 1045,
    drawer: 1045,
    modal: 1055,
    dialog: 1055,
    popover: 1070,
    tooltip: 1080,
    toast: 1090
  ),
  $zindex-levels
);

Utilities API

Position utilities are declared in our utilities API in scss/_utilities.scss. Learn how to use the utilities API.

"z-index": (
  property: z-index,
  class: z,
  values: $zindex-levels,
),