CSS — Z-index

The z-index property controls the stacking order of elements when they overlap. Elements with a higher z-index number will appear on top of those with lower numbers. This is very useful when working with modals, dropdown menus, or pop-ups. For example, you can ensure a navigation menu appears above all other content by giving it a higher z-index. Remember, z-index only works on elements with a position value other than static, like relative or absolute.

.modal { position: absolute; z-index: 10; }