JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html>
<html lang="en" manifest="/cache.manifest">
<head>
    <meta charset="utf-8" />
    <meta http-equiv="x-ua-compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1" />
    <meta name="keywords" content="Openreach, Site Survey">
    
    <title>Online Survey Form for Sitec IS - Openreach</title>
    <link rel="icon" href="https://cdn.forms.office.net/forms/images/favicon.ico" />

    <link rel="stylesheet" href="../css/main.css">  
    <link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/font-awesome/4.7.0/css/font-awesome.min.css"> 

    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
    <script src="javascript/parsley.min.js"></script>

                                <script>
                                                // Dynamic header & footer  
                                    $(function(){ 
                                        $("#header").load("../header.html");  
                                        $("#footer").load("../footer.html");  
                                    }); 
                                </script>  
                                <script>
                                       window.onbeforeunload = function() {
                                        return "Data will be lost if you leave the page, are you sure?";
                                        };  
                                        $(document).on("submit", "form", function(event){
                                         window.onbeforeunload = null;
                                        });
                                </script>

                                <script>
                                                // Switching between the form pages
                                    function show(shown, hidden) {
                                        document.getElementById(shown).style.display='block';
                        ...