JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
    <div class="orange">1</div>
    <div class="blue">2</div>
    <div class="green">3</div>
</div>

CSS

/*************** MOBILE *************/

.container {
    display: flex;
    flex-direction: column;
    height: 200px;
}

div.orange {
    background-color: orange;
}

div.blue {
    order: -1;
    background-color: aqua;
}

div.green {
    background-color: lightgreen;
}

.container > div {
    width: 100%;
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}



/***************************/

@media screen and (min-width:800px) {
    .container {
        flex-wrap: wrap;
    }
    div.orange {
        flex-basis: 100%;
        width: 50%;
    }
    div.blue {
        flex-basis: 50%;
        width: 50%;
        order: 0;
    }
    div.green {
        flex-basis: 50%;
        width: 50%;
    }
}