JSFiddle - React, Tailwind, and code Playground

HTML

<div id="container">
    <div id="one">
        This is DIV number one.
    </div>
    <div id="two">
        This is DIV number two.
        <br>
        This is DIV number two.
        <br>
        This is DIV number two.
        <br>
        This is DIV number two.
        <br>
        This is DIV number two.
        <br>
        This is DIV number two.
        <br>
        This is DIV number two.
    </div>
</div>

CSS

#container {
    box-align: start;
    display: -moz-box; -moz-box-orient: horizontal; display: -webkit-box; -webkit-box-orient: horizontal; }

#one, #two {
    background: rgb(230,235,240);
    padding: 20px;
}
#two {
    -moz-box-flex: 1; -webkit-box-flex: 1;
    margin-left: 10px;
}