* Use sans-serif font in TikZ, match font for units
I think this makes the diagrams easier to read and also makes unit not
looking weird in the HTML version. Not sure why match ain't the default
* Use palatino for main serif font
- Andale mono
- SourceSansPro for non-serif
* Disable Andale mono font for typwriter
It is not available on GitHub CI. Need to find an alternative.