package previewimport "strings"// Render highlights src with the active theme.func Render(lang string, src []byte) string { lex := registry.Get(lang) // 292 lexersif lex == nil {return strings.TrimSpace(string(src)) } toks := lex.Tokenise(src) out := Paint(toks, Theme) // 3 themesreturn out}01Code — line numbers, real token colours, no editor required.