JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mainContainer">
    <div class="backStrip"> 
        <span id="infoText">Written By Banmeet Singh</span>
    </div>
    <ul id="thumbsButtons"></ul> <span id="nextArrow">></span>
    <span id="sidelogo">Thinking Forward</span>
    <ul id="thumbsList">
        <li>
            <img class="forward" src="http://placehold.it/350x150" alt="Alternate Text" /> <span class="headerInfo">Josh Kloss</span>
        </li>
        <li>
            <div class="thumbOverlay"><span>adasd</span> </div>
            <img class="forward" src="http://placehold.it/350x150" alt="Alternate Text" />
        </li>
        <li>
            <img class="forward" src="http://placehold.it/350x150" alt="Alternate Text" />
        </li>
        <li>
            <img class="forward" src="http://placehold.it/200x100" alt="Alternate Text" />
        </li>
        <li>
            <img class="forward" src="http://placehold.it/350x150" alt="Alternate Text" />
        </li>
        <li>
            <img class="forward" src="http://placehold.it/200x100" alt="Alternate Text" />
        </li>
    </ul>
    <div id="counterContainer">3 of 10</div>
</div>

CSS

html, body {
    min-height: 100%;
    height: 100%;
}
body {
    width: 100%;
    margin: 0;
    padding: 0;
}
#thumbsList {
    height: 76%;
    white-space: nowrap;
    margin: 0;
    padding: 0;
    line-height: 0px;
    top: 13%;
    left: 80px;
    list-style-type: none;
    top: 13%;
    position: absolute;
}
#thumbsList li {
    /*display: inline;REMOVE THIS*/
    display: inline-block;
    /*ADD THIS*/
    height: 100%;
    /*ADD THIS*/
    position: relative;
}
#thumbsList li img {
    /*max-width: 100%; REMOVE THIS*/
    max-width: calc(100vw - 96px);
    /*ADD THIS*/
    height: 100%;
    transition: all 0.8s ease;
}
.Absolute-Center {
    margin: auto;
    position: absolute;
    top: 0;
    left: 0;
    bottom: 0;
    right: 0;
}
.backStrip {
    background-color: #2d2d2d;
    border-bottom: 1px solid #1a1a1a;
    height: 35px;
    position: relative;
    z-index: 22;
    position: fixed;
    width: 253px;
    top: 43px;
    height: 79px;
    left: 85px;
}
#infoText {
    color: white;
    font-style: italic;
    padding-top: 10px;
    float: right;
    margin-right: 10px;
    font-family: sans-serif;
    font-size: 12px;
}
#mainContainer {
    height: 100%;
    width: 100%;
    position: fixed;
    z-index: 1;
    box-sizing: border-box;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    border: 8px solid #2D2D2D;
    margin: 0px;
    overflow-x: auto;
}
#thumbsButtons {
    list-style: none;
    position: fixed;
    bottom: 6%;
    left: 46%;
    z-index: 22;
}
#counterContainer {
    position: fixed;
    bottom: 5%;
    left: 50%;
    right: 50%;
    font-family: verdana;
    font-weight: bold;
    width: 100px;
}
#thumbsButtons li {
    float: left;
    margin-left: 11px;
    font-size: 16px;
    font-family: verdana;
}
#thumbsButtons li:hover {
    cursor: pointer;
}
#nextArrow {
    position: fixed;
    right: 10px;
    top: 43%;
    z-index: 13333;
    font-size: 100px;
    color: white;
    font-family: helvetica;
   ...