代码
提交代码
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <title>Document</title> </head> <style> @media screen and (max-width:400px){ html,body{ background:red; } } </style> <body> </body> </html>
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