Style Guide

Generic

This guide can be ignored for data files that are not to be viewed in an editor.
120 character per line for all source files.
Avoid white space errors like trailing spaces.

Python Code

We mostly follow PEP8. Read below to see the differences.
120 characters per line. PyCharm does this automatically, other editors can be configured for it.
Strings in core code will be "strings". In other words: double quote your strings.
Strings in worlds should use double quotes as well, but imported code may differ.
Prefer format string literals over string concatenation, use single quotes inside them: f"Like {dct['key']}"
Use type annotations where possible for function signatures and class members.
Use type annotations where appropriate for local variables (e.g. var: List[int] = [], or when the type is hard or impossible to deduce.) Clear annotations help developers look up and validate API calls.
Worlds that do not follow PEP8 should still have a consistent style across its files to make reading easier.

Markdown

We almost follow Google's styleguide. Read below for differences.
For existing documents, try to follow its style or ask to completely reformat it.
120 characters per line.
One space between bullet/number and text.
No lazy numbering.

HTML

Indent with 2 spaces for new code.
kebab-case for ids and classes.

CSS

Indent with 2 spaces for new code.
{ on the same line as the selector.
No space between selector and {.

JS

Indent with 2 spaces.
Indent case inside switch with 2 spaces.
Use single quotes.
Semicolons are required after every statement.