JSFiddle - React, Tailwind, and code Playground

HTML

<div>
    <div>
        <span class="hr"></span>
    </div>

    <div>
        <span class="hr"></span>
    </div>

    <div>
        <span class="hr"></span> <!-- I need this -->
    </div>
</div>

CSS

div {
    box-sizing:border-box;
    border:1px solid rgb(200,200,200);
    padding:10px;
    height:10px;
    
    background:rgb(240,240,240);
    
}

.hr {
    display:block;
    width:100%;
    height:10px;
}

div *:last-child *:last-child {
    background:red;
}