In my web app, I’m displaying a “notification” DIV.
I would like to “dim” the rest of the page, so that the notification DIV stands out even more when displayed.
Is there a reasonably easy way of doing so?
This question is only concerned with visual effects, NOT the functionality of the rest of the page.
Here is an example of the functionality I found elsewhere on the web (though in this case the dialog was a pop-up JS one, and not a DIV):

You can use this CSS:
Working Example
In the example above, this bit creates overlay:
Dialog box is then added on that overlay element with higher
z-index.