<!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>宽高比</title>
<style>
.container {
height: 300px;
width: 500px;
padding: 16px;
overflow: auto;
resize: both;
border: 1px solid gray;
}
.content {
position: relative;
border: 1px solid teal;
}
.content::before {
content: '';
display: block;
/* 以下两种皆可以，不过第一种比较直观看出宽高比 */
/* padding-bottom: calc(100% / ( 16 / 9)); */
padding-top: 56.25%;
}
.content > :first-child {
position: absolute;
top: 0;
right: 0;
bottom: 0;
left: 0;
}
/* 这种方式对兼容性要求较高 */
.content2 {
border: 1px solid teal;
aspect-ratio: 16 / 9;
}
</style>
</head>
<body>
<div class="container">
<div class="content">
<p>保持宽高16：9</p>
</div>
</div>
<div class="container">
<div class="content2">
<p>保持宽高16：9</p>
</div>
</div>
</body>
</html>
