main {
    width: 90%;
    margin: 0 auto;
    padding-top: 150px;
}

ul.nav {
    list-style-type: none;
    margin:0;
    padding:0;
}

ul.nav li {
    display: inline-block;
}

ul.nav li a {
    text-align: center;
    text-decoration: none;
    background-color: #CCCCCC;
    padding: 10px;
}