JSFiddle - React, Tailwind, and code Playground

HTML

<div class="sidebar">
        
        <ul>
        
            <a href="#"><li>Home</li></a>
            <a href="#"><li>About</li></a>
            <a href="#"><li>Work</li></a>
            <a href="#"><li>Contact</li></a>
        
        </ul>
    
    </div>
    
    <div class="content">
    
        <a href="#"><img src="http://placehold.it/500x400"></a>
        <a href="#"><img src="http://placehold.it/500x400"></a>
        <a href="#"><img src="http://placehold.it/500x400"></a>
        <a href="#"><img src="http://placehold.it/500x400"></a>
        <a href="#"><img src="http://placehold.it/500x400"></a>
    
    </div>

CSS

html, body {
  margin: 0;
  padding: 0;
  background-color: red;
  font-family: 'Open Sans', sans-serif; }

.sidebar {
  background-color: #fff;
  width: 100px;
  height: 100%;
  position: fixed;
  text-align: center;
  padding: 50px 10px;
  transition: .15s; }
  .sidebar:hover {
    width: 200px;
    transition: .15s; }
  .sidebar:hover + .content {
    margin-left: 220px;
    transition: .15s; }
  .sidebar img {
    max-width: 100px;
    margin-bottom: 50px; }
  .sidebar ul {
    list-style-type: none;
    margin: 0;
    padding: 0; }
    .sidebar ul a {
      color: #000;
      text-decoration: none; }
      .sidebar ul a li {
        opacity: 1;
        transition: .15s; }
        .sidebar ul a li:hover {
          opacity: .6;
          transition: .15s; }

.content {
  margin-left: 120px;
  transition: .15s; }

.content img {
    width:100%;
    height:100%;
}

.content a {
    width:25%;
    height: 100px;
    float: left;
}