JSFiddle - React, Tailwind, and code Playground

HTML

<div class="block">
    <span class="text">text</span>
</div>

CSS

.block {
    width: 100px;
    height: 100px;
    text-align: center;
    vertical-align: middle;
    font-size: 20px;
    background-color: #eee;
    
}
.block .text {
    opacity: 0;
}

.block:hover {
    background-color: #bbb;
    transition: 0.5s all;
}

.block:hover .text {
    transition: 0.5s all;
    opacity: 1;
}