简单案例如下,详情参考MDN
<!DOCTYPE html>
<html>
<head>
<style type="text/css">
.a p {color: red;}
.b p {color: orange;}
.c p {color: yellow}
.c {color: yellow;}
.d {color: green;}
.e {color: blue;}
.f {color: blueviolet;}
p.f {color: violet;}
p {color: pink}
/* p.f{color: violet;} 紫罗兰紫色 浏览器无法识别??? 错,可以识别!!!*/
</style>
</head>
<body>
<div class="a">
<div class="b">
<p>爷div样式a,父div样式b,本身无样式的P元素</p>
</div>
</div>
<div class="b">
<div class="a">
<p>爷div样式b,父div样式a,本身无样式的P元素</p>
</div>
</div>
.b p {color: orange;}在css表中后写入,比.a p优先级高</br>
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<div class=""