z-index is the CSS property that helps control layout by providing a third axis to arrange content.
Several MUI components utilize
z-index, employing a default z-index scale in MUI
that has been designed to properly layer drawers, modals, snackbars, tooltips, and more.
z-index values start at an arbitrary number, high and specific enough to ideally avoid conflicts:
- mobile stepper: 1000
- speed dial: 1050
- app bar: 1100
- drawer: 1200
- modal: 1300
- snackbar: 1400
- tooltip: 1500
These values can always be customized.
You will find them in the theme under the
zIndex key of the theme.
Customization of individual values is discouraged; should you change one, you likely need to change them all.