1 原始

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>a的美化</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .nav{
            width: 960px;
            height: 40px;
            margin: 100px auto;
            border: 1px solid #000;
        }
        
        ul{
            list-style: none;
        }
        
        ul>li{
            float: left;
            width: 120px;
            height: 40px;
            line-height: 40px;
            text-align: center;
        }
        .nav a{
            display: block;
            width: 120px;
            height: 40px;
        }

        .nav a:link, .nav a:visited{
            text-decoration: none;
            color: #ffffff;
            background-color: purple;
        }

        .nav a:hover{
            /*因为状态的切换表示从一种基础态转换，所以不用再写一次link中的如下代码*/
            /*text-decoration: none;*/
            /*color: #ffffff;*/
            /*background-color: purple;*/
            background-color: orangered;
        }
    </style>
</head>
<body>
    <div class="nav">
        <ul>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
        </ul>
    </div>
</body>
</html>

2 优化，去掉link，visited

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>a的美化</title>
    <style>
        *{
            margin: 0;
            padding: 0;
        }
        .nav{
            width: 960px;
            height: 40px;
            margin: 100px auto;
            border: 1px solid #000;
        }
        
        ul{
            list-style: none;
        }
        
        ul>li{
            float: left;
            width: 120px;
            height: 40px;
            line-height: 40px;
            text-align: center;
        }
        .nav a{
            display: block;
            width: 120px;
            height: 40px;
            text-decoration: none;
            color: #ffffff;
            background-color: purple;
        }

        .nav a:hover{
            background-color: orangered;
        }
    </style>
</head>
<body>
    <div class="nav">
        <ul>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
            <li><a href="">网站栏目</a></li>
        </ul>
    </div>
</body>
</html>