Dialogs and popovers: modern overlays that layer correctly

The pop-up interfaces that today's sites build with the browser's own dialog and popover features now open, close and stack the way they do in the reference browser. A modal dialog, a confirmation box, a sign-in panel, a cookie or age gate, opens centered on top of the page with a dimmed backdrop behind it, and a script can open it, close it and read which button was pressed. Pop-up menus, tooltips and disclosure panels built with the popover feature show and hide on cue, a button wired to a popover toggles it on click, and the open and close events fire so a page's own code stays in step. The piece that makes this work is the top layer: these overlays now paint above everything else on the page no matter where they sit in the document or how the rest of the page is stacked, so a dialog is never trapped behind other content, and a page's own backdrop styling is honored. Sites that use neither are unchanged. It moves the overall platform score to 69.