Good question :). Markdown in general does not "support" colored letters, that is: it does not have special syntax sugar for it. If you wanna color letters in markdown you need to workaround it via html / css. Markdown officially supports html tags. People came up with some tricks to add colors to their markdown: https://stackoverflow.com/a/65626850

Personally I went with a different approach in Nitropage: There is richtext content and there is plaintext content. In richtext content you can color the text using the richtext editor, in plaintext content (and markdown) you have to decide by yourself if you wanna do the shenanigans mentioned in the Stackoverflow thread or live with the single color.