JSFiddle - React, Tailwind, and code Playground

HTML

<div id="wrapper">
    <div id="parent"></div>
    <div id="shadow"></div>
</div>

CSS

#wrapper { 
    height: auto;
    width: 84px;
    position: relative;
}
#parent {
    background-color: #3D668F;
    height: 54px;
    width: 100%;
    position: relative;
    z-index: 10;
}
#shadow {
    background-color: #3D668F;
    height: 8px;
    width: 80px;
    margin-left: -40px;
    position: absolute;
    bottom: 0px;
    left: 50%;
    z-index: 5;
    box-shadow-bottom: 0px 2px 4px #000000;
    -moz-box-shadow: 0px 2px 4px #000000;
    -webkit-box-shadow: 0px 2px 4px #000000;
}