Z-index
Use our low-level `z-index` utilities to quickly change the stack level of an element or component.
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. High-level z-index values are used for overlay components like modals and tooltips.
Overlays
Bootstrap 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.
Read about them in the z-index layout page.
Component approach
On some components, we use our low-level z-index values to manage repeating elements that overlap one another (like buttons in a button group or items in a list group).
Learn about our z-index approach.
CSS
Sass maps
Customize this Sass map to change the available values and generated utilities.
Sass utilities API
Position utilities are declared in our utilities API in scss/_utilities.scss. Learn how to use the utilities API.