JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li></li>
    <li></li>
    <li></li>
</ul>

CSS

li {
    height: 4em;
    display:block;
    position:relative;
    border:1px solid #000;
    border-radius:0 10px 10px 10px;
    padding:0;
    margin: 0 0 20px 0;
}

li:before {
    border:1px solid #000;
    border-bottom:0 none;
    border-radius:10px 10px 0 0;
    background-color:#fff;
    content:"";
    display:block;
    position:absolute;
    height:10px;
    width:100px;    
    left:-1px;
    top:-11px;
}