JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="box box1">
        <div class="inside-box"></div>
        <div class="inside-box"></div>
        <div class="inside-box last-box"></div>
    </div>
    <div class="box box2">
        <div class="inside-box"></div>
        <div class="inside-box"></div>
        <div class="inside-box last-box"></div>
    </div>
    <div class="box box3">
        <div class="inside-box"></div>
        <div class="inside-box"></div>
        <div class="inside-box last-box"></div>
    </div>
</div>

CSS

.container {
    border: 1px solid red;
    width:90%;
    height: 100px;
    display: flex;
}

.box {
    border: 1px solid purple;
    flex: 0 1 33%;
    margin: 0 20px;
    align-self: stretch;
    justify-self: stretch;
    width: fill;
    display: flex;
    flex-direction: column;
}

.inside-box {
    border: 1px solid green;
    min-height: 0.5rem;
    width: 100%;
    flex: 0;
}

.last-box {
    background-color: pink;
    flex: 1;
}