Match all .mui-content after .mui-bar-nav (ie other classes or elements at the same level)
E.g:
<!DOCTYPE html>
<html lang="zh-cn">
<head>
<meta charset="UTF-8">
<title>Document</title>
<style>
.a ~ .b {
color: red;
}
</style>
</head>
<body>
<div class="a">a
<div class="b">b1</div>
</div>
<div class="b">b2</div>
<div class="b">b3</div>
</body>
</html>It can be seen that b1 does not change color, and b2 and b3 change color.