JSFiddle - React, Tailwind, and code Playground

HTML

<div id="header">
       <a href="index.html"></a><img class="bottom" src="images/luuk1.png">
      <img class="top" src="images/luuk2.png">   </div>
    <div id="menubar">
      <ul> 
      	<li><a href="index.html">Home</a></li>
        <li><a href="about.html">About</a></li> 
        <li><a href="work.html">Work</a></li>
        <li><a href="skills.html">Skills</a></li>
        <li><a href="tutorials.html">Tutorials</a></li> 
      </ul>
    </div>
    <div id="containerAbout">
    	<h1>About</h1>
      <div style="display: block;" id="contentboxAbout">
        <h3>Ik luister naar de naam Roel Cuijpers</h3>
        <p>Lorem ipsum dolor sit amet, consectetuer adipiscing elit. Aenean commodo ligula eget dolor. Aenean massa. Cum sociis natoque penatibus et magnis dis parturient montes, nascetur ridiculus mus. Donec quam felis, ultricies nec, pellentesque eu, pretium quis, sem. Nulla consequat massa quis enim. Donec pede justo, fringilla vel, aliquet nec, vulputate eget, arcu. In enim justo, rhoncus ut, imperdiet a, venenatis vitae, justo. Nullam dictum felis eu pede mollis pretium. Integer tincidunt. Cras dapibus. Vivamus elementum semper nisi. Aenean vulputate eleifend tellus. Aenean leo ligula, porttitor eu, consequat vitae, eleifend ac, enim. Aliquam lorem ante, dapibus in, viverra quis, feugiat a, tellus. Phasellus viverra nulla ut metus varius laoreet. Quisque rutrum. Aenean imperdiet. Etiam ultricies nisi vel augue. Curabitur ullamcorper ultricies nisi. Nam eget dui.</p>
      </div>
    </div>
    <div id="footer">
      <li>Contact:</li>
      <li>Roel Cuijpers</li>
      <li>[email protected]</li>
      <li>0625250775</li>
    </div>

CSS

#header {
    margin-left: auto;
    margin-right: auto;
    margin-top: 15px;
    position: relative;
    width: 100%;
}
#header img {
    border-radius: 10px;
    left: 0;
    position: absolute;
    transition: opacity 1s ease-in-out 0s;
    width: 100%;
}
@-moz-keyframes cf3FadeInOut {
0% {
    opacity: 1;
}
45% {
    opacity: 1;
}
55% {
    opacity: 0;
}
100% {
    opacity: 0;
}
}
#header img.top {
    animation-direction: alternate;
    animation-duration: 7s;
    animation-iteration-count: infinite;
    animation-name: cf3FadeInOut;
    animation-timing-function: ease-in-out;
}
#menubar ul li {
    display: inline;
    font-family: dominikthin;
    font-size: 46px;
    list-style-type: none;
    margin-right: 80px;
    padding-left: 30px;
    padding-top: 20px;
    text-decoration: none;
    width: 100%;
}
#menubar a:link {
    color: hsl(69, 6%, 77%);
    text-decoration: none;
}
#menubar a:visited {
    color: hsl(69, 6%, 77%);
}
#menubar a:hover {
    color: hsl(0, 0%, 100%);
}
#menubar {
    background-color: hsl(240, 1%, 17%);
    border: 1px solid hsl(0, 0%, 100%);
    height: 51px;
    line-height: 20px;
    margin: 261px auto 0;
    position: absolute;
    text-align: center;
    vertical-align: middle;
    width: 1280px;
}
#containerAbout {
    background-color: hsl(0, 0%, 100%);
    height: 530px;
    margin-top: 330px;
    opacity: 0.5;
    position: fixed;
    width: 1280px;
}
#containerIndex {
    background-color: hsl(0, 0%, 100%);
    height: 530px;
    margin-top: 330px;
    opacity: 0.5;
    position: fixed;
    width: 1280px;
}
#containerWork {
    background-color: hsl(0, 0%, 100%);
    height: 530px;
    margin-top: 330px;
    opacity: 0.5;
    position: fixed;
    width: 1280px;
}
#containerIndex h1 {
    color: hsl(257, 100%, 6%);
    font-family: dominikthin;
    font-size: 50px;
    margin-left: 20px;
    margin-top: 490px;
    position: fixed;
}
#containerWork h1 {
    color: hsl(257, 100%, 6%);
    font-family: dominikthin;
   ...