JSFiddle - React, Tailwind, and code Playground

HTML

<div id="sidenav">
    <li> <a>
        SameSIZE
    </a>

    </li>
</div>

CSS

#sidenav li {
    border : 1px solid red;
    margin-top : 10px;
    width : 250px;
    height : 100px;
}
#sidenav li a {
    border : 1px solid green;
    margin: 0px auto;
    display:block;
    width : parent;
    height : 100%;
}