JSFiddle - React, Tailwind, and code Playground

HTML

<div>

    <div class="close-btn"><div class="x">X</div></div>
</div>

CSS

div { 
    padding: 10px; 
    width: 200px; 
    height: 100px; 
    border: 1px solid #c2c2c2; 
    background-color: #FFEFEF; 
    margin: 40px;
}

.close-btn { 
    border: 1px solid red;
    background-color: white;
    border-radius:13px;
    height:26px;
    width:26px;
    line-height:20px;
    font-size:20px;
    margin:0px;
    margin-top:-10px;
    padding:0px;
    cursor:pointer;
}