Since moving from the Wiki we have used the `sphinx_rtd_theme` which has worked well but has become a little dated and has had slow development. This changes to use "Furo" instead.
Furo is a lightweight theme that is responsive and has native dark mode support.
Dark mode is one of the major enhancements but this change also brings:
- Content is slightly larger making text and images easier to view
- Site navigation and page navigation is split into two navigation trees. The site navigation is on the left and page on the right if the page has multiple headings.
- Return to top button
- Content is centered on the screen which helps with wide monitors
- No more breadcrumbs
So far the caveat that I have noticed with this is slower compile times and larger pages, this is due to the better sidebar navigation.
This change also brings a lot of simplifications to customizations that we made to the `sphinx_rtd_theme`. There is still likely room for improvement in the future.
