JSFiddle - React, Tailwind, and code Playground

HTML

<div class="Container">
    <div class="LeftColumn">Short column</div>
    <div class="RightColumn">A column with a lot of information in. Even when this column gets larger than the smaller column, the smaller column's background still extends all the way down (as illustrated by the blue colour). The same happens when the left column gets larger than the right column.</div>
</div>
<div>Hello</div>

CSS

.LeftColumn,
.RightColumn{
    float: left;
    width: 100px;
    padding-bottom: 30000px;
    margin-bottom: -30000px;
    background: blue;
    color: white;
}
.RightColumn{
    width: 200px;
    background: yellow;
    color: black;
}
.Container{
    width: 300px;
    margin: 10px auto;
    overflow: hidden;
    border: 1px solid black;
}