JSFiddle - React, Tailwind, and code Playground

HTML

<div class="contentBox">
    <button onclick="expand(this)"> + </button>
    <p>
        Text Text Text 
    </p>
</div>

CSS

.contentBox {
    background-color:#777777;
}

JavaScript

function expand(btn) {
    btn.parentNode.style.height = "200px";
}