老师，请问这样写正确吗

<!DOCTYPE html>
<html>
    <head>
        <meta charset="UTF-8">
        <title>margin外边距</title>
        <style type="text/css">
            * {
                margin: 0;
                padding: 0;
             }
            ul{
                list-style:none;width:300px;height:600px;
                background-color:pink;
                padding-top:40px;
            }
            li{
                width:200px;height:50px;background-color:yellow;
                /*样式补充*/
                margin-top:40px;
                margin-left:40px;
                padding-top:40px;
                
                
            }
            .top{margin-top:80px;}
        </style>
    </head>
    <body>
        <ul>
            <li class="top">HTML</li>
            <li>CSS</li>
            <li>JavaScript</li>
        </ul>
    </body>
</html>

weibo_执著的弧线_0 2019-02-28

源自：盒子模型 3-24 编程练习