为啥我这个多出很多栏？
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>导航菜单练习</title>
<style type="text/css">
*{margin: 0; padding: 0; font-size: 14px;}
ul{list-style: none; width: 100px;}
a{text-decoration:none; display: block; height: 30px; line-height: 30px; width: 100px; background-color: #ccc; margin-bottom: 1px; text-indent: 10px;}
a:hover{background-color: #f60;}
</style>
</head>
<body>
<ul>
<li><a href="#">首页</li>
<li><a href="#">新闻</li>
<li><a href="#">产品</li>
<li><a href="#">售后</li>
<li><a href="#">联系</li>
</ul>
</body>
</html>
运行后是这样
