W3School TIY
编辑您的代码：
<html> <head> <style type="text/css"> #mostImportant {color:red; background:yellow;} </style> </head> <body> <h1 id="mostImportant">This is important!</h1> <p>This is a paragraph.</p> <p>This is a paragraph.</p> <p>This is a paragraph.</p> <p>...</p> </body> </html>
查看结果: