JSFiddle - React, Tailwind, and code Playground

HTML

<div class="tasiyici">
    <div class="alteleman">
    </div>
</div>

CSS

.tasiyici {
    width: 100px;
    height: 100px;
    border: 1px solid #ddd;
}
.alteleman {
    width: 50%;
    height: 50%;
    border: 1px solid #000;
    margin: 10px;
}