JSFiddle - React, Tailwind, and code Playground

HTML

<!DOCTYPE html> 
<html>
<head>
<meta charset="utf-8">
<title>Kuchencraft Bewerbung</title>
<link href="jquery-mobile/jquery.mobile.theme-1.0.min.css" rel="stylesheet" type="text/css"/>
<link href="jquery-mobile/jquery.mobile.structure-1.0.min.css" rel="stylesheet" type="text/css"/>
<script src="jquery-mobile/jquery-1.6.4.min.js" type="text/javascript"></script>
<script src="jquery-mobile/jquery.mobile-1.0.min.js" type="text/javascript"></script>
<script src="contact.js" type="text/javascript"></script>
</head> 
<body> 
<div data-role="page" id="page1">
  <div data-role="header" data-theme="b">
    <h1>Bewerben?</h1>
  </div>
  <div data-role="content" data-theme="a">Du möchtest auf unserem Server spielen? Dann bewirb dich gleich jetzt mit folgendem Formular!
    <hr>
            <div class="contact-thankyou" style="display: none;">
            Danke. Deine Bewerbung wurde abgesendet!
        </div>
        <div class="contact-form">
            <p class="mandatory">* Pflichtfeld</p>
            <form action="bewerbung.html" method="get">
            <div data-role="fieldcontain" class="text-field">
                <label for="firstname">Name*:</label>
                <input type="text" name="firstname" value="" placeholder="" class="required" id="firstname" />
            </div>
            <div data-role="fieldcontain" class="text-field">
                <label for="email">Email Adresse*:</label>
                <input type="email" name="email" value="" placeholder="" class="required" id="email"  />
            </div>
            <div data-role="fieldcontain" class="text-field">
                <label for="mobilephone">Ingamename*:</label>
                <input type="text" name="ingamename" value="" placeholder="" class="required" id="ingamename" />
            </div>
            <div data-role="fieldcontain">
                <label for="message">Wieso möchtest du bei uns spielen?*:</label>
                <textarea name="message" id="message" placeholder=""...