<html>
<head>
<style type="text/css">
*{
padding: 0;
margin: 0;
}
body :first-child{
position: absolute;
left: 200px;
width: 100px;
height: 100px;
top: 200px;
background-color: blue;
}
body :empty{
position: absolute;
left: 200px;
width: 100px;
height: 100px;
top: 200px;
background-color: red;
z-index: 50px
}
body :last-child{
position: absolute;
left: 200px;
width: 100px;
height: 100px;
top: 200px;
background-color: green;
}
</style>
</head>
<body>
<div>1</div>
<div></div>
<div>2</div>
</body>
</html>
chrome F12显示这样
GlaDoss
乱舞的旋律
卡迪亚兹