JSFiddle - React, Tailwind, and code Playground

HTML

<div class="hello">
    <h1>Hello</h1>
</div>

CSS

.hello{
    position: relative;
       
    background: black;
    color: white;
    padding: 20px;  
    width: 200px;
    height: 200px;
}

.hello:before{
    content: "";
    position: absolute;
    display: block;
    top: 0;
    left: -5px;
    right: -5px;
    bottom: 0;
    border-left: 5px solid red;
    border-right: 5px solid red;
}