<head>
<style>
.outer {
position: relative;
width: 25%;
padding-bottom: 25%;
}
.inner {
position: absolute;
width: 100%;
height: 100%;
background-color: #00FF00;
}
</style>
</head>
<body>
<div class="outer">
<div class="inner"></div>
</div>
</body>Editor is loading...
