Pagination buttons are not displayed properly

ecemces

Page numbers are shown as plain text. And cursor is text select on hover. It might be because of my css files but I don't know what changes I should do.

$(document).ready(function () {
        $('#example').DataTable({
        pagingType: 'simple_numbers',
        order:[[ 0, 'desc' ]],
        searching: false,
        info: false,
        pageLength: 21,
        dom: 'rtip',
        language: {
        paginate: {
        previous: '<img src="sl.png"/>', next: '<img src="sg.png"/>',
    }
  }
        
    });
});

Thanks in advance.