JSFiddle - React, Tailwind, and code Playground

HTML

<div class='parent'>
    <span class='child1'>1</span>
    <span class='child2'>2</span>
</div>

CSS

.parent {
    width: 100px;
    height: 100px;
    background: #000;
    color: #fff;
    text-align: center;
}
.child1 {
    width: 50px;
    height: 50px;
    background: #f00;
    display: block;
}
.child2 {
    width: 50px;
    height: 50px;
    background: #00f;
    display: none;
}
.parent:hover .child1 {
    display: none;
}
.parent:hover .child2 {
    display: block;
}