<html><head><style type="text/css">h1, h2, h4 {color:silver;}h2, h3 {background:gray;}h1, h4, b {background:white;}h3 {color:white;}b {color:gray;}</style></head><body><h1>这是 heading 1</h1><h2>这是 heading 2</h2><h3>这是 heading 3</h3><h4>这是 heading 4</h4><p>这是一段<b>普通</b>的段落文本。</p></body></html>