JSFiddle - React, Tailwind, and code Playground

HTML

<div class="deck">
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
    <div class="card"></div>
        
</div>

CSS

/* add border + padding to width */
*
{
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
}

html, body
{
    height: 100%;
    padding:0;
    margin:0;
}

.deck
{
    height: inherit;
    margin:0;
}

/* change the 6 to desired column/row count */
.deck .card
{
    width: calc(100% / 6 - 10px);
    height: calc(100% / 4 - 10px);
    margin: 5px;
    background-color: silver;
    border-radius: 4px;
    border: 1px solid gray;
    float: left;
}