lovecoding
/
W260426


			
				
					
						
						
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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>
        html{
            font-size: 20px;
        }
        #box{
            /* rem单位 她是根元素的字体大小的倍数 html的font-size */
            /* 20rem = 20*20 = 400px */
            width: 20rem;
            height: 20rem;
            background-color: red;
        }
        #div1{
            font-size: 20px;
        }
        #div2{
            width: 10em;
            height: 10em;
            background-color: blue;
        }
    </style>
</head>
<body>
    <div id="box"></div>
    <div id="div1">
        <div id="div2"></div>
    </div>
</body>
</html>