lovecoding
/
web0331


			
				
					
						
						
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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>
        * {
            margin: 0;
            padding: 0;
        }
        html,body {
            width: 100%;
            height: 100%;
        }
        body {
            display: flex;
            justify-content: center;
            align-items: center;
        }
        #box {
            width: 200px;
            height: 200px;
            background: #00f;
        }
    </style>
</head>
<body>
    <div id="box"></div>
</body>
</html>