* Update typography colours

All headings are now #444444 (heading)
All sidebar/legend items are now #444444 (passive)

* Fix jumpy legend position

* Fix stripes and sidebar layout

* Reduce font-size on mobile to 15px effectively

* Add sidebar collapsing sections and active styling

* Update sidebar size and padding

* Fix links in mdx using react-router-dom Link

* Fix Loading page design

* Add basic implementation for <ScrollToTop />

* Fix internal links on index pages

This will need further fixes in the plugin

* Fix internal links on /docs/

* Update react-static-plugin-md-pages to fix lost state

* Add usePrefetch hook to home screen to increase load consistency

* Upgrade react-static-plugin-md-pages to fix page update

* Add missing suspense rethrow to custom catch code

* update <Loading /> so that it isn't affected by throws/suspense

* remove duplicate <Article /> parts

* WIP: enable the 404 page on the built app

* Upgrade react-static-plugin-md-pages to remove page data requirement

* Fix path resolution for internal links properly

* Fix homepage links in staging and add link to logo

* Fix local relative internal links on same level

* fix markdown links from other pages

* Fix several hash anchor links
Co-authored-by: Will Golledge <will.golledge@formidable.com>
Co-authored-by: wgolledge <wiggiumg@gmail.com>