Improving the two webpages of a simple web interface to a metadata-removal tool

Mat2 is an open-source metadata removal tool. Currently the two main ways of using it are either the command line interface, of a file-browser extension. I recently wrote a web interface to make it more accessible to non-technical people (see the demo instance here), but it doesn’t look super-pretty. Some journalist organizations already deployed their own private instance, but their users are complaining about the lack of prettiness and usability of it.

Since I don’t know much about UX/accessibility, help would be more than welcome ♥