IE浏览器Css选择的优先问题

1 .pagination {
2     
3     border: none;
4     border-radius: 3px;
5     margin-left:30%;
6     -moz-border-radius: 3px;
7     -webkit-border-radius: 3px;
8 }

1 .gigantic.pagination {
2     margin: 10px 0;
3     margin-left:20%;
4 
5 }

      <div class="pagination" style="width:auto;">
        <a href="#" class="first" data-action="first">&laquo;</a>
         <a href="#" class="previous"
            data-action="previous">&lsaquo;</a>
        <input  id="pageNum"  type="text" readonly="readonly" data-max-page="40" />
        <a href="#" class="next" data-action="next">&rsaquo;</a> 
        <a href="#" class="last"
            data-action="last">&raquo;</a>
    </div>