#nav a{
        text-decoration: none;
        background: red;
        color: black;
        width: 300px;
        display: block;
        text-align: center;
        padding-top: 5px;
        padding-bottom: 5px;
        float: left;
       }
       .clearfloat{
        clear: both;
       }

       #nav{
        margin-left: auto;
        margin-right: auto;
        width: 900px;
        margin-bottom: 10px;
        margin-top: 10px;
       }
       #nav a:hover{
           background-color: white;           
       }
       #nav .active{
            background-color: orange;
       }