JSFiddle - React, Tailwind, and code Playground

HTML

<div class="c">
    <div class="fc">
        <div class="fc">
            <div class="fia">a</div>
            <div class="fib">b</div>
        </div>
        <div class="fic">c</div>
    </div>

    <div class="fc">
        <div class="fc">
            <div class="fia fiw">a</div>
            <div class="fib">b</div>
        </div>
        <div class="fic">c</div>
    </div>
</div>

CSS

.fc {
    display: flex;
    flex-wrap: wrap;
}
.fia {
    flex-basis: 100px;
}
.fiw {
    width: 100px;
}

/*
 * Colors for clarity, but otherwise irrelevant:
 */
.c {
    color: white;
    font-family: monospace;
    font-size: 4em;
}
.fc {
    background-color: grey;
}
.fia {
    background-color: red;
}
.fib {
    background-color: green;
}
.fic {
    background-color: blue;
}