lovecoding
/
web0715


			
				
					
						
						
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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{
            height: 100px;
            background-color:red;
            width: calc(100% - 300px);
        }
    </style>
</head>
<body>
    <div class="box"></div>
</body>
</html>