JSFiddle - React, Tailwind, and code Playground
HTML
<a class="close"></a>
CSS
.close{
background-color:#000;
font-size:25px;
color:#fff;
font-family:helvetica;
width:18px;
height:18px;
border-radius:20px;
border:2px solid #fff;
box-shadow:0 0 5px #000;
-webkit-backface-visibility:hidden;
}
.close:after{
content:"+";
position:absolute;
z-index:20;
font-size:25px;
-webkit-transform:rotate(45deg);
margin-top:-7px;
margin-left:3px;
-webkit-font-smoothing:none;
}