JSFiddle - React, Tailwind, and code Playground

HTML

<div id='test'>
<div id='a'>Hi</div>
<div id='b'>Bye</div>
    <div>Three</div>
</div>

CSS

#test {
    display: flex;
    flex-direction: column;
}
#a { order: 0; }
#b { order: -1; }
#a + #b { color: red; }