JSFiddle - React, Tailwind, and code Playground

by RomanFF

HTML

<div class="o2t-element">i</div>

<div class="o2t-element--hidden">Скрытый элемент</div>

CSS

.hover--hidden {
    opacity: 0;
    transition: 1s opacity;
}
.o2t-element:hover ~ .o2t-element--hidden {
    opacity: 1;
}