JSFiddle - React, Tailwind, and code Playground

HTML

<div class="b-red-block">
    <div class="b-three-coll">
        <div class="b-three-coll__coll"></div>
        <div class="b-three-coll__coll"></div>
        <div class="b-three-coll__coll"></div>
        <div class="clear"></div>
    </div>
    <div class="b-green-block">
        Lorem ipsum dolor sit amet, consectetur adipisicing elit. Illum magni labore harum ex repellat voluptates provident sit animi ipsam incidunt inventore praesentium voluptate blanditiis maiores aliquid enim tenetur dolores! Est.
    </div>
</div>

CSS

*{margin:0; padding:0}
.clear{clear:both}

.b-red-block{
    border: 3px solid red;
}
.b-three-coll__coll{
    width: 33%;
    float: left;
    height: 100px;
    border: 1px solid blue;
}

.b-green-block{
    border: 3px solid green;
}