.pg_ul {
    display:table;
    text-align:center;
}
.pg_li{
    float:left;
}
    .pg_li > a {
        padding: 5px 15px;
        color: #000;
        background: #ccc;
        position: relative;
        margin-right: 2px;
    }
        .pg_li > a.active {
            color: #fff;
            background: #000;
        }