<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<style>
body {
background: #6e28d9;
padding: 0 24px;
margin: 0;
height: 100vh;
color: white;
display: flex;
justify-content: center;
align-items: center;
}
</style>
</head>
<body>
<script>window.onload = function () {
em = document.querySelector(".block");
em.onmouseover = function () {
this.innerHTML = "да";
}
em.onmouseout = function () {
this.innerHTML = "Видно?";
}
}</script>
<div class="block"
style="display:block;background-color:black;border-radius:3vh;width:7vw;height:20vh;padding:5vh 1vw 1vh 1vw;text-align:center;font-size:80%;">
Видно?</div>
</body>
</html>