请用 HTML+CSS 实现一个定宽定高元素在容器中的水平和垂直居中。
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title></title>
<style>
*{
margin: 0;
padding: 0;
}
</style>
</head>
<body>
<div style="width: 500px; height: 500px; background-color: antiquewhite; position: relative; text-align: center;">
<div style="width: 200px; height: 200px; background-color: brown;position: absolute; left: 0; top: 0;bottom: 0;right: 0;
margin: auto;"></div>
</div>
</body>
</html>