51help TIY
码：
<html> <head> <style type="text/css"> #mostImportant {color:red; background:yellow;} </style> </head> <body> <h1>This is important!</h1> <p>This is a <em id="mostImportant">paragraph</em>.</p> <p>This is a paragraph.</p> <p>This is a paragraph.</p> <p>...</p> </body> </html>
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