JSFiddle - React, Tailwind, and code Playground

HTML

<div class="bg"><a href="#">Ссылка</a></div>

CSS

div {
  width: 100px;
  height: 100px;
  border: 1px solid #000;
 }
 a:hover {
   display: block;
   width: 100%;
   height: 100%;
   background-color: #050;
 }