Check out example codes for "how to serve css in golang". It will help you in understanding the concepts better.

Code Example 1

// if you keep all css and js in a static folder
// you can use this

func main() {
  http.Handle("/static/", http.StripPrefix("/static/", http.FileServer(http.Dir("static"))))
}

Code Example 2

http.Handle("/", http.FileServer(http.Dir("css/")))

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