JSFiddle - React, Tailwind, and code Playground

HTML

<nav2>
    	<ul>
            <li><a class="but1" href="#">Кнопка</a></li>              
        </ul>
     
    </nav2>

CSS

nav2{
    display:block;
    position:fixed;
    left:0px;
    top:60px;
    width:220px;
    height:600px;
    background-color:#0FF;						
		}
        nav2 ul li {
					list-style:none;
				}
				nav2 ul li a{
					display:block;
					text-decoration:none;
					width:220px;
					height:100px;
					color:#999;
					background-color:#CCC;
				}
				nav2 ul li a:hover{
					display:block;
					text-decoration:none;
					width:220px;
					height:100px;
					color:#999;
					background-color:#009;
				}
				nav2 ul li a:active{
					display:block;
					text-decoration:none;
					width:220px;
					height:100px;
					color:#999;
					background-color:#C30;
				}
				.but1{
					font-family:Arial, Helvetica, sans-serif;
					font-size:48px;
																											
				}