JSFiddle - React, Tailwind, and code Playground

HTML

<div class="div-a">
    <div class="div-b"></div>
</div>

CSS

body {
    background-color:black;
}
.div-a {
    border-top:10px solid transparent;
    margin: 50px auto;
    width:160px;
    height:200px;
    background-color:white;
}
.div-b {
    margin:-20px auto;
    border-radius: 10px 10px 0 0;
    width:140px;
    height:50px;
    background-color:gray;
}