Minor - fix buttons.

main/gradebook/gradebook_display_certificate.php

@@ -171,14 +171,14 @@ if ($filter) {
 
 echo '<div class="btn-group">';
 $url = api_get_self().'?action=generate_all_certificates'.'&'.api_get_cidReq().'&cat_id='.$cat_id.'&filter='.$filterOfficialCode;
-echo Display::url(get_lang('GenerateCertificates'), $url, array('class' => 'btn'));
+echo Display::url(get_lang('GenerateCertificates'), $url, array('class' => 'btn btn-default'));
 
 $url = api_get_self().'?action=delete_all_certificates'.'&'.api_get_cidReq().'&cat_id='.$cat_id.'&filter='.$filterOfficialCode;
-echo Display::url(get_lang('DeleteAllCertificates'), $url, array('class' => 'btn'));
+echo Display::url(get_lang('DeleteAllCertificates'), $url, array('class' => 'btn btn-default'));
 
 if (count($certificate_list) > 0) {
     $url = api_get_self().'?action=export_all_certificates'.'&'.api_get_cidReq().'&cat_id='.$cat_id.'&filter='.$filterOfficialCode;
-    echo Display::url(get_lang('ExportAllCertificatesToPDF'), $url, array('class' => 'btn'));
+    echo Display::url(get_lang('ExportAllCertificatesToPDF'), $url, array('class' => 'btn btn-default'));
 }
 echo '</div>';
 
@@ -204,7 +204,7 @@ if (count($certificate_list) == 0 ) {
             echo '<td width="30%">'.get_lang('Date').' : '.api_convert_and_format_date($value_certificate['created_at']).'</td>';
             echo '<td width="20%">';
             $url = api_get_path(WEB_PATH).'certificates/index.php?id='.$value_certificate['id'];
-            $certificates = Display::url(get_lang('Certificate'), $url, array('target'=>'_blank', 'class' => 'btn'));
+            $certificates = Display::url(get_lang('Certificate'), $url, array('target'=>'_blank', 'class' => 'btn btn-default'));
             echo $certificates;
             echo '<a onclick="return confirmation();" href="gradebook_display_certificate.php?sec_token='.$token.'&cidReq='.$course_code.'&action=delete&cat_id='.$cat_id.'&certificate_id='.$value_certificate['id'].'">
                     '.Display::return_icon('delete.png',get_lang('Delete')).'