JSFiddle - React, Tailwind, and code Playground

HTML

<div id="content">
    <div id="action">
        <div id="buy" class="action">Buy</div>
        <div id="sell" class="action">Sell</div>
    </div>
    <div id="other">test</div>
</div>

CSS

#content {
    width: 400px;
}
#action {
	width: 100%;
    
}

#action:after {
    content: "";
    display: table;
    clear: both;
}

.action {
   float: left;
    text-align: center;
	width: 50%;
}

#other {
    background-color: gray;
}