The Unicode trap I had to design around in a LinkedIn formatter

I built a small tool for formatting LinkedIn posts, and the deceptively simple part was also the most important part:

styled text is not formatting. It is Unicode substitution.

That sounds obvious once you say it out loud, but it changes the product decision.

When someone clicks bold in a normal editor, the text usually remains the same text with a style applied around it. When someone uses a LinkedIn-style formatter, the tool often converts normal characters into mathematical Unicode characters that only look bold or italic.

For example, a plain A may become a styled Unicode character that visually resembles a bold A.