So I've updated it a bit since the initial version. Originally I was trying to identify different uses of things in the application but that just led to a huge mess of names and I couldn't work out where to go next.
So I've redone the classification entirely and based it off the default joplin style code instead with the idea to try and classify it in a more "atomic" way so that the later components can be identified using those base classes.

I've also added a font section which needs an awful lot of work still. Just in the default application (without taking into account all the font sizes (other than the plain/default) within the actual notes themselves) I have identified 15 unique font styles (combinations of font-family, font-size, font-weight and font-style) but I'm yet to fully work out which fonts are inherited on different systems over others.
Those combinations don't take into account the colour - not even within the light theme which is the only one I'm targetting for the moment with the dark theme to come once I can figure just one out.
If you are interested in what is used where I have listed examples in comments in the html file against each of the divs for the font lines.

An example of what I've added:

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