You’ve already got the building blocks with $(#layerid).show(); and what I posted previously. A bit of basic styling and… done; positioning the layer base into all 4 corners will automatically be responsive, so all you’d need to do is use fluid values (e.g. %), and maybe the odd media query, to style the inner popup for mobile. I don’t think you need a plugin at all. In fact, it will probably take longer to search for one than roll your own. How about taking a few design ideas from the link you posted (inspect it in dev tools) and replicate the look of that one?
