JSFiddle - React, Tailwind, and code Playground

HTML

<ul>
    <li>Red</li>
    <li>Red</li> 
    <li>Red</li>  
    <li>Green</li>
</ul>

CSS

ul li
{
    background-color:red;
} 

ul li:last-child
{
    background-color:green;
}

ul li:not(last-child)
{
    border:3px blue solid;
}