Goals for my theme switcher:
* switch-off the Matrix 20th anniversary (re)inspired theme I hacked in March (similar to 2003 April & May: https://tantek.com/log/2003/04.html https://tantek.com/log/2003/05.html) while keeping the option
* minimal system to add more for fun
Next steps: more themes, and possibly dark/light modes of each theme that auto-switched based on media queries from an OS-level dark mode preference if any.