lovecoding
/
W250511


			
				
					
						
						
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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>
        .box{
            width: 400px;
            height: 400px;
            background-color: blue;
        }

        /* 媒体查询 */
        /* 当屏幕宽度小于等于500px 时  把box的背景颜色改为红色 */

        @media screen and (max-width:500px){
            .box{
                background-color: red;
            }
        }
        @media screen and (max-width:800px ) and (min-width:501px){
            .box{
                background-color: green;
            }
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>