<!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>Document</title>
<style>
div{
width: 100px;
height: 100px;
background-color: red;
}
div:first-child{
float: left;
}
div:last-child{
background-color: blue;
/* 清除浮动元素对兄弟元素影响 */
clear: both;
}
</style>
</head>
<body>
<div></div>
<div></div>
</body>
</html>