As I said the title, How do I get mutiple files like html, css, javascript, and php in static using main.go

package main

import (
    "fmt"
    "log"
    "net/http"
)

func formHandler(w http.ResponseWriter, r *http.Request) {
    if err := r.ParseForm(); err != nil {
        fmt.Fprintf(w, "ParseForm() err: %v", err)
        return
    }
    fmt.Fprintf(w, "POST request successful")
    name := r.FormValue("name")
    address := r.FormValue("address")
    fmt.Fprintf(w, "Name = %s\n", name)
    fmt.Fprintf(w, "Address = %s\n", address)
}

func helloHandler(w http.ResponseWriter, r *http.Request) {
    if r.URL.Path != "/hello" {
        http.Error(w, "404 not found", http.StatusNotFound)
        return
    }
    if r.Method != "GET" {
        http.Error(w, "method is not supported", http.StatusNotFound)
        return
    }
    fmt.Fprintf(w, "hello!")
}

func main() {
    fileServer := http.FileServer(http.Dir("./static/"))
    http.Handle("/static", fileServer)
    http.HandleFunc("/form", formHandler)
    http.HandleFunc("/hello", helloHandler)

    fmt.Printf("Starting server at port 8080\n")
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal(err)
    }
}

also there are multiple files like this

but page shows wrong style, does anyone how to get these multiple files?

or how do i fix this? fileServer := http.FileServer(http.Dir("./static/"))