把样式名或id写在一起，用逗号隔开
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>信息详情</title>
<style type="text/css">
#box-1, #box-2, #box-3, #box-4{
border: 1px solid blueviolet;
width: 100%;
height: 300px;
}
</style>
</head>
<body>
<div id="box-1">
<span>6666</span>
</div>
<div id="box-2">
<span>6666</span>
</div>
<div id="box-3">
<span>6666</span>
</div>
<div id="box-4">
<span>6666</span>
</div>
</body>
</html>
原文：https://www.cnblogs.com/wangshuazi/p/9663451.html