overlayThe 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.cssCSSlimitedhttps://drafts.csswg.org/css-position-4/#overlayhttps://developer.mozilla.org/docs/Web/CSS/Reference/Properties/overlaycss.properties.overlaycss.properties.overlay.autocss.properties.overlay.nonehttps://nowyoucanuse.com/features--overlay.html