lovecoding
/
W250913


			
				
					
						
						
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							<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box1{
            width: 400px;
            height: 400px;
            background-color: red;
        }
        .box2{
            width: 300px;
            height: 300px;
            background-color: blue;
        }
        .box3{
            width: 200px;
            height: 200px;
            background-color: green;
        }
        /* 子代选择器 */
        .box1 > div{
            background-color: yellow;
        }
    </style>
</head>
<body>
    <div class="box1">
        <div class="box2">
            <div class="box3"></div>
        </div>
    </div>
</body>
</html>