JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <h1>Hello</h1>
</div>

CSS

@media screen and (max-width: 800px) {
    .container h1 {
        font-size: 10px;
    } 
}

.container h1 {
    font-size: 50px;
}