Jamie Lentin

We can use [MutationObservers](https://developer.mozilla.org/en-US/docs/Web/API/MutationObserver) to trigger autoplay events via. CSS state classes.

Do we want to support audio subtitles during narration? Or rely on the tourstops itself? https://developer.mozilla.org/en-US/docs/Web/API/TextTrack

The visibility for tour_resume, tour_previous, tour_next being CSS driven is also a reasonable choice. It can be automatic.

I've had a bash at updating the diagram for the above: [ToursTimeline.pptx](https://github.com/OneZoom/OZtree/files/8770390/ToursTimeline.pptx) The coloured blocks now show the CSS class that a tourstop gets at each point, and we have...

The above reworks button visibility / actions to also work via CSS. Also, we rework interaction to firstly be cancellable like a DOM event would be at run time, and...

There's still dregs of exit_confirm (on interaction) left in the system, it doesn't really work though. Better would be to implement it using https://github.com/OneZoom/OZtree/issues/550 later on.

Whilst they're stored as python files, that's really just a convenient serialisation format web2py uses. When reading/writing, it's reading/writing a dict: https://github.com/web2py/web2py/blob/6da8479444031c6188d64382a7c785e96cd42323/gluon/languages.py#L166-L175 What if the seams were loosened here and...

> @jrosindell > I think more broadly this is part of making all the 'settings' including language and colour scheme parsable via the URL This has already happened via. #369...

This was mostly solved by throwing away code. But I've added a bunch more tests whilst looking at this.

My preferred options here would be: * Finish the job, move [the code in models/db.py](https://github.com/OneZoom/OZtree/blob/main/models/db.py#L144-L158) to [get_mailer()](https://github.com/OneZoom/OZtree/blob/main/modules/ozmail.py#L5-L24), make this the only source of mail objects. * Add a ``smtp.force_sender`` option...