JSFiddle - React, Tailwind, and code Playground

HTML

<div class="one">One</div>
<div class="two">Two</div>
<div class="one two">One Two</div>

CSS

div.one:not(.two), div.two:not(.one) {
    background:red;
}

div {
    width: 50px;
    height: 50px;
    margin: 10px;
    border: 1px solid black;
}