<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
* {
box-sizing: border-box
}
.container {
width: 100%;
padding: 24px;
}
.box {
width: 100%;
padding-top: 100%;
background: green;
}
</style>
</head>
<body>
<div class="container">
<div class="box"></div>
</div>
</body>
</html>