You say that only two files need modification, in that case you could organize your repository just to have those needed files.
An improving idea, would be to identify the changed styles and create a small python script to modify them.
After that we could add a GUI to allow people to customize the Report and Log output.
For my side, if you do a nice customizable script, I could incorporate in RIDE as a new plugin or even as options for rebot and be part of the Robot Framework tools.
actually, I’ve changed my career track to the developer path and do not do any RF related stuff any more.
If I remember correctly, there wasn’t anything complicated, pure HTML/CSS.
I can ask a guy, who came to QA automation to replace me if he is interested in maintaining it.