JSFiddle - React, Tailwind, and code Playground

HTML

<div class="grid">
    <div class="wide">
        <div>Prio 1</div>
        <div>Prio 4</div>
        <div>Prio 5</div>
        <div>Prio 6</div>
        <div>Prio 7</div>
    </div>
    <div class="narrow">
        <div>Prio 2</div>
        <div>Prio 3</div>
        <div>Prio 3</div>
    </div>
</div>

CSS

.grid {
    overflow: hidden;
    background-color: gray;
}

.wide {
    background: blue;
    float: left;
    clear: left;
    width: 80%;
}

.narrow {
    background: green;
    float: right;
    clear: right;
    width: 20%;
}