Style guides for Google-originated open-source projects
Google's style guide for Python code. Obviously not the law, not even always a good suggestion, but worthy of consideration.
Reddit thread where the Textual Markdown widget was announced.
Also includes the rather hilarious comment "I wish there were more full blown app examples out there", back when Textual was pretty damn new and barely out of the initial "CSS branch" release.
Useful article talking about unicode stuff.
Page is annoying to read though with daft gimmicks.