JSFiddle - React, Tailwind, and code Playground

HTML

<div id="mydiv">
    <div class="workaround"></div>
</div>

CSS

#mydiv { 
    background-color:#f00;
    height:100px;
    width:100px;
    box-shadow: inset 0 0 10px 0 rgba(255, 255, 255, 1);
    padding:0 2px;
}
#mydiv .workaround {
    background-color:#f00;
    width:100%;
    height:10px;
}