JSFiddle - React, Tailwind, and code Playground

HTML

<div class="vash d1">121212</div>
<div class="vash d1">121212</div>
<div class="vash d1">121212</div>
<div class="vash d1">121212</div>
<div class="vash d1">121212</div>

CSS

.d1:nth-of-type(2n){
    background:red;
}
.d1:nth-of-type(2n-1){
    background:blue;
}