The Article Page

- set FontSize, FontFamily, theme
- function to compose Subtitle plus moment for date etc

- useState for readingProgressAnchorIndex
- update reading progress every 5 seconds (use scroll position)
- handles horizontal scrolling of article
- something about mathjax
- open the original article from link
- show toast notifications
- reparses the article?
- can share the article

- it lays out images

- sidebar for highlights?
- has a "report issues" ModalWrapper
- shortcut keys
- render tweets
- render instagram posts
- has a highlight controller