W3School TIY
编辑您的代码：
<html> <head> <style type="text/css"> .important {font-weight:bold;} .warning {font-style:italic;} .important.warning {background:silver;} </style> </head> <body> <p class="important">This paragraph is very important.</p> <p class="warning">This is a warning.</p> <p class="important urgent warning">This paragraph is a very important warning.</p> <p>This is a paragraph.</p> <p>...</p> </body> </html>
查看结果: