Web platform features explorer

overlay

The overlay CSS property, used as an allow-discrete CSS transition, prevents a top layer element, such as a popover or a <dialog>, from being removed from the top layer before it has finished animating. You can't set the value of the overlay property; only use it as transition property.

Status

Limited availability

MDN documentation

Browser support

Usage (according to Chrome Platform Status)

~0.041% of page loads. More data at chromestatus.