html css继承样式

CSS:

#tiaoshi{ background-color:#090; list-style:none;color:#F30;}
#tiaoshi li{color:#fff;}
#tiaoshi span li{color:#93C;}

HTML:

<div id="tiaoshi">
<li>继承一</li>
<span>我是第默认<li>继承二</li></span>
</div>