Super cool--and very fast! Anyone looking to collaborate on these can easily add Kontxt (https://www.kontxt.io) right on to them and have localized discussions directly on page-parts.
I used React client-side, Node server-side, and MySQL as the db. I only mentioned Kontxt here because I demoed it for Thomson Reuters because it could be helpful for their legal professionals as a collaboration tool after they find documents via their WestLaw legal search product, and your tool reminded me of it. I actually used Kontxt as a sales pitch to highlight their annual report and add some calculations and explanations about how much money they could make. Nice work, again!