为什么"测试"类不适用于<p>标签和<span>标签的使用？
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en">
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type" />
<title>Newsletter template</title>
<!--general stylesheet-->
<style type="text/css">
p { padding: 0; margin: 0; }
a {
color: #455670; text-decoration: underline;
}
test {
margin: 20; font-family: "Helvetica Neue"; font-size: 20px; font-weight: normal; color: #666666; line-height: 15px !important;
}
</style>
</head>
<body>
<p class="test"><span class="test"> Check the spelling of the words you typed.</span></p>
</body>
</html>