JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li class="bla pups">bla</li>
    <li class="bla">bla</li>
    <li class="bla">bla</li>
    <li class="bla pups">bla</li>
    <li class="bla">bla</li>
    <li class="bla pups">bla</li>
    <li class="bla">bla</li>
    <li class="bla pups">bla</li>
    <li class="bla pups">bla</li>
</ul>

CSS

.bla {
    color: #006600;
}

.bla.pups:nth-child(2n) {
    color: #ff0000;
}

.bla.pups:nth-child(2n+1) {
    color: #0000ff;
}