JSFiddle - React, Tailwind, and code Playground

HTML

<div class="word">
    <div class="letter">Hover Me!</div>
</div>

CSS

body
{
    background: yellow;
}
.letter
{
    float: left;
}

.photo
{
background-image:url(http://mk7vrlist.altervista.org/backgrounds/1.png);
}

JavaScript

$(document).ready(function(){
    $('.letter').mouseenter(function () {
        $("body").addClass("photo");
    });
    $('.letter').mouseleave(function () {
        $("body").removeClass("photo");
    });
});