This is not yet perfect, and may even be klunky, but just about works. Once you make changes in Authorea, you need to go back and git pull the document. Then convert the document to markdown and work on the document and then push again, this time only the html file (do not push everything, you can keep them in the staging area: this is a git issue, read on git). If you mess these things up, then a whole world of merge nightmares pop up. Everything else should work just as planned. Just keep in mind the citation codes, for some reason the showing of the codes in html did not work. But at least using this workflow (that is writing in markdown, converting it to html, pushing it to Authorea, changing the document on Authorea, pulling changes, converting back to markdown, making changes, converting forwarding to html and pushing through git), you can get by using markdown and writing on the web. You need to use git quite efficiently for this workflow to be successful. There are easier workflows for other editors such as Overleaf, but at least this offers a great flexibility of writing online on the web and on your machine locally using markdown. Also, interfacing with github adds to the beauty of working with github directly. You can add and update tables, figures, citations, and format citations in any way you like with basic pandoc. The scheme does not work very well in Firefox developer edition, but on most other browsers, the system works well.