JSFiddle - React, Tailwind, and code Playground

HTML

<div class="example" id="example1">
<p>
Lorem ipsum dolor sit amet, consectetur adipiscing elit. Ut a dolor dui. Sed arcu sapien, molestie quis euismod et, varius a ipsum.</p>
</div>

CSS

.example{
    border: 1px solid #0055ee;
    margin: 5px auto;
    padding: 15px;
    width: 250px;
}

#example1{
    position:relative;
}

#example1 p:before{
    content: ' ';
    background:blue;
    position:absolute;
    top:0px;
    left:0px;
    width:100%;
    height:100%;
    opacity:0.8;
    z-index:-1;
}