JSFiddle - React, Tailwind, and code Playground

HTML

<div>test</div>

CSS

div {
        padding : 5px;
        border : 15px solid red;
        border-top: 0;
        position:relative;
        padding-top: 20px;
    }
    div:before {
        content:' ';
        display:block;
        background :  teal;
        height:15px;
        padding:0 15px;
        width:100%;
        position:absolute;
        top: 0;
        left:-15px;
    }