JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bottom">
    <div class="col">one</div>
    <div class="col">two</div>
    <div class="col">three</div>
</div>

CSS

div.bottom {
    height: 200px;
    width: 80%;
    margin-left: auto;
    margin-right: auto;
    margin-top: none;
    margin-bottom: none;
    border-top: 4px solid #00ccff;
    border-bottom-left-radius: 15px;
    border-bottom-right-radius: 15px;
    background-color: #575757;
}

div.col {
    float: left;
    width: 33%;
}