JSFiddle - React, Tailwind, and code Playground

HTML

<div class="box">1</div>
<div class="box">2</div>
<div class="box hidden">3</div>
<div class="box">4</div>
<div class="box">5</div>
<div class="box">6</div>
<div class="box">7</div>
<div class="box">8</div>
<div class="box">9</div>
<div class="box">10</div>
<div class="box">11</div>
<div class="box">12</div>
<div class="box">13</div>

CSS

.box {
  background-color: #a00;
  color: #fff;
  float: left;
  height: 64px;
  margin: 5px 2px;
  text-align: center;
  width: 64px;
}

/* .hidden {
  display: none;
} */

 .box:not([class*="hidden"]):nth-of-type(4n+1) {
  clear: left;
}