JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="block">block1</div>
    <div class="block">block2</div>
    <div class="block">block3</div>
</div>

CSS

.container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    align-items: center;
    align-content: center;

    height: 400px;
    border-radius: 5px;
    border: 2px solid #999;
}
.block {
    width: 100px;
    height: 100px;    
    text-align: center;
    line-height: 100px;        
    border-radius: 5px;
    border: 2px solid darkgreen;
}