JSFiddle - React, Tailwind, and code Playground

HTML

<div id="test_div"></div>

CSS

#test_div:before { 
        position:absolute; 
        width:100%; 
        padding:1px; 
        top:0; 
        content: '';
        left:-1px;
        background:#000; 
        height:1px; }
    
    #test_div { 
        border: 1px solid #E3E3E3; 
        border-top:0; 
        width: 300px;
        height: 250px; 
        position:relative; }