JSFiddle - React, Tailwind, and code Playground

HTML

<div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div><div class="time">Time</div>

CSS

div:nth-child(12n+4) {
    background-color:#000;
}

div:nth-child(12n+10) {
    background-color:#999;
}