JSFiddle - React, Tailwind, and code Playground

HTML

<div class="row-fluid">
    <div class="span2">span2</div>
    <div class="span7">span7</div>
    <div class="span3">span3</div>
</div>

CSS

.row-fluid > div {
    width: 100px;
    height: 100px;
    border: 1px solid red;
}
@media (max-width: 763px) {
    .row-fluid {
        display: flex;
        flex-wrap: wrap;
        flex-direction: column;
    }
    .span2 {
        order: 1;
    }
    .span7 {
        order: 3;
    }
    .span3 {
        order: 2;
    }
}