JSFiddle - React, Tailwind, and code Playground

HTML

<div class="content">
    X
</div>

CSS

.content {
    position: relative;
    font-size: 50px;
    color: black;
}

.content:after {
    content: 'X';
    color: red;
    width: 50%;
    position: absolute;
    overflow: hidden;
}