JSFiddle - React, Tailwind, and code Playground

HTML

<div class="wrapper">
    <div class="left">
        <p>sdhfjashdfjka asdj fkajdskfjaklsd jfkajsdfkajkfja kld</p>
        <p>sdhfjashdfjka asdj fkajdskfjaklsd jfkajsdfkajkfja kld</p>
        <p>sdhfjashdfjka asdj fkajdskfjaklsd jfkajsdfkajkfja kld</p>
        <p>sdhfjashdfjka asdj fkajdskfjaklsd jfkajsdfkajkfja kld</p>
        <div class="marked">
        <p>sdhfjashdfjka asdj fkajdskfjaklsd jfkajsdfkajkfja kld</p>
        <p>sdhfjashdfjka asdj fkajdskfjaklsd jfkajsdfkajkfja kld</p>
        </div>
        <p>sdhfjashdfjka asdj fkajdskfjaklsd jfkajsdfkajkfja kld</p>
    </div>
    <div class="right"></div>
</div>

CSS

body {
    margin: 0;
    padding: 0;   
}

.wrapper {
    position: relative;
    background: black;
    color: #fff;
    width: 80%;
    margin: 0 auto;
}

.wrapper:after {
    content: '';
    overflow: hidden;
    height: 0;
    display: block;
    clear: both;   
}

.left {
    width: 50%;
    float: left;
    z-index: 3;
}

.right {
    width: 50%;
    height: 300px;
    float:left;
    background: orange;
}

.marked {
    position: relative;
}
.marked:before {
    position: absolute;
    content: '';
    top: 0;
    bottom: 0;
    left: -20px;
    right: -90%;
    background: rgba(184, 58, 237, 0.7);
    padding: 0 90% 0 20px;
}

.marked>* {
    position: relative;   
}