[Feature request] Use class instead style

[zyxkad]

Why should we use class, not hard code style:

• Dark themes are more popular now, people doesn't only like light theme. class can ensure people are using their perfect theme.
• Free Configuration. We can customize many fun themes in our css file either.
• Security. Style is more easier to get XSS attack, so things like bluemonday will clear the style and none highlighted codes will be send to the client

[Yuelioi]

hI, you can use cutom configuration, goldmark-highlighting is base on https://github.com/alecthomas/chroma, so you can

goldmark.New(
  goldmark.WithExtensions(
    highlighting.NewHighlighting(
	  highlighting.WithStyle("base16-snazzy"),
        highlighting.WithFormatOptions(
					chromahtml.ClassPrefix("highlight-"),
					chromahtml.WithClasses(true),
					chromahtml.LineNumbersInTable(true),
					chromahtml.WithAllClasses(true),
					chromahtml.WithLineNumbers(true),
				),
			),
		),
	)

[rcarmo]

This should be in the README, I don't think anyone wants hard-coded colors anymore.