console 命令行工具 X clear

console

<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<meta name="viewport" content="width=, initial-scale=">
	<meta http-equiv="X-UA-Compatible" content="">
	<title></title>
</head>
<body>
	<div class="div1">div1</div>
    <div class="div2">
        div2
        <div class="div3">div3</div>
        </div>   
</body>
</html>

*{
    margin: 0;
    padding: 0
}
div{
    width: 200px;
    height: 200px;
    background-color: lightblue;
    border: 1px solid lightgoldenrodyellow
}


.div1{
    margin-bottom: 50px;
  
}
.div2{
    margin-top: 50px;
    /* 父级设置一个transform属性可以使子元素fixed布局相对该父级 */
    transform: translate(0,0)

}

.div3{
    width: 50px;
    height: 50px;
    background-color: red;
    position: fixed;
    top: 10px;
    left: 10px;
}