JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box"></div>

CSS

.box {
    position: relative;
    width: 100px;
    height: 100px;
    z-index: 1;
    background: tomato;
}
.box:before,
.box:after {
    content: "";
    position: absolute;
    z-index: -1;
    bottom: 4px;
    width: 50px;
    height: 20px;
    box-shadow: 0 2px 10px #000;
}
.box:before {
    left: 10px;
    -webkit-transform: rotate(-5deg);
}
.box:after {
    right: 10px;
    -webkit-transform: rotate(5deg);
}