diff --git a/application/views/appointments/cookie_notice_modal.php b/application/views/appointments/cookie_notice_modal.php
index 007b87b4..61ee08ee 100644
--- a/application/views/appointments/cookie_notice_modal.php
+++ b/application/views/appointments/cookie_notice_modal.php
@@ -9,7 +9,9 @@
                 <p><?= $cookie_notice_content ?></p>
             </div>
             <div class="modal-footer">
-                <button type="button" class="btn btn-light" data-dismiss="modal"><?= lang('close') ?></button>
+                <button type="button" class="btn btn-outline-secondary" data-dismiss="modal">
+                    <?= lang('close') ?>
+                </button>
             </div>
         </div>
     </div>
diff --git a/application/views/appointments/privacy_policy_modal.php b/application/views/appointments/privacy_policy_modal.php
index ca5393fd..246d4734 100644
--- a/application/views/appointments/privacy_policy_modal.php
+++ b/application/views/appointments/privacy_policy_modal.php
@@ -9,7 +9,9 @@
                 <p><?= $privacy_policy_content ?></p>
             </div>
             <div class="modal-footer">
-                <button type="button" class="btn btn-light" data-dismiss="modal"><?= lang('close') ?></button>
+                <button type="button" class="btn btn-outline-secondary" data-dismiss="modal">
+                    <?= lang('close') ?>
+                </button>
             </div>
         </div>
     </div>
diff --git a/application/views/appointments/terms_and_conditions_modal.php b/application/views/appointments/terms_and_conditions_modal.php
index a2208192..0522e88b 100644
--- a/application/views/appointments/terms_and_conditions_modal.php
+++ b/application/views/appointments/terms_and_conditions_modal.php
@@ -9,7 +9,9 @@
                 <p><?= $terms_and_conditions_content ?></p>
             </div>
             <div class="modal-footer">
-                <button type="button" class="btn btn-light" data-dismiss="modal"><?= lang('close') ?></button>
+                <button type="button" class="btn btn-outline-secondary" data-dismiss="modal">
+                    <?= lang('close') ?>
+                </button>
             </div>
         </div>
     </div>
diff --git a/application/views/backend/calendar.php b/application/views/backend/calendar.php
index e9b1bc2e..8c786509 100755
--- a/application/views/backend/calendar.php
+++ b/application/views/backend/calendar.php
@@ -519,7 +519,7 @@
                 </form>
             </div>
             <div class="modal-footer">
-                <button id="cancel-custom-availability-period" class="btn btn-light" data-dismiss="modal">
+                <button id="cancel-custom-availability-period" class="btn btn-outline-secondar" data-dismiss="modal">
                     <i class="fas fa-ban mr-2"></i>
                     <?= lang('cancel') ?>
                 </button>
@@ -550,7 +550,7 @@
                 </div>
             </div>
             <div class="modal-footer">
-                <button id="close-calendar" class="btn btn-light" data-dismiss="modal">
+                <button id="close-calendar" class="btn btn-outline-secondary" data-dismiss="modal">
                     <i class="fas fa-ban mr-2"></i>
                     <?= lang('cancel') ?>
                 </button>
diff --git a/application/views/backend/customers.php b/application/views/backend/customers.php
index 9f83ee86..564724f9 100755
--- a/application/views/backend/customers.php
+++ b/application/views/backend/customers.php
@@ -35,10 +35,10 @@
 
                     <div class="input-group-addon">
                         <div>
-                            <button class="filter btn btn-light" type="submit" title="<?= lang('filter') ?>">
+                            <button class="filter btn btn-outline-secondary" type="submit" title="<?= lang('filter') ?>">
                                 <i class="fas fa-search"></i>
                             </button>
-                            <button class="clear btn btn-light" type="button" title="<?= lang('clear') ?>">
+                            <button class="clear btn btn-outline-secondary" type="button" title="<?= lang('clear') ?>">
                             <i class="fas fa-redo-alt"></i>
                             </button>
                         </div>
@@ -61,14 +61,14 @@
                     <?php endif ?>
 
                     <?php if ($privileges[PRIV_CUSTOMERS]['edit'] === TRUE): ?>
-                    <button id="edit-customer" class="btn btn-light" disabled="disabled">
+                    <button id="edit-customer" class="btn btn-outline-secondary" disabled="disabled">
                         <i class="far fa-edit mr-2"></i>
                         <?= lang('edit') ?>
                     </button>
                     <?php endif ?>
 
                     <?php if ($privileges[PRIV_CUSTOMERS]['delete'] === TRUE): ?>
-                    <button id="delete-customer" class="btn btn-light" disabled="disabled">
+                    <button id="delete-customer" class="btn btn-outline-secondary" disabled="disabled">
                         <i class="far fa-trash-alt mr-2"></i>
                         <?= lang('delete') ?>
                     </button>
@@ -80,7 +80,7 @@
                         <i class="far fa-check-square mr-2"></i>
                         <?= lang('save') ?>
                     </button>
-                    <button id="cancel-customer" class="btn btn-light">
+                    <button id="cancel-customer" class="btn btn-outline-secondary">
                         <i class="fas fa-ban mr-2"></i>
                         <?= lang('cancel') ?>
                     </button>
diff --git a/application/views/backend/services.php b/application/views/backend/services.php
index 026fd896..844fe992 100755
--- a/application/views/backend/services.php
+++ b/application/views/backend/services.php
@@ -51,10 +51,10 @@
 
                             <span class="input-group-addon">
                         <div>
-                            <button class="filter btn btn-light" type="submit" title="<?= lang('filter') ?>">
+                            <button class="filter btn btn-outline-secondary" type="submit" title="<?= lang('filter') ?>">
                                 <i class="fas fa-search"></i>
                             </button>
-                            <button class="clear btn btn-light" type="button" title="<?= lang('clear') ?>">
+                            <button class="clear btn btn-outline-secondary" type="button" title="<?= lang('clear') ?>">
                             <i class="fas fa-redo-alt"></i>
                             </button>
                         </div>
@@ -73,11 +73,11 @@
                                 <i class="far fa-plus-square mr-2"></i>
                                 <?= lang('add') ?>
                             </button>
-                            <button id="edit-service" class="btn btn-light" disabled="disabled">
+                            <button id="edit-service" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-edit mr-2"></i>
                                 <?= lang('edit') ?>
                             </button>
-                            <button id="delete-service" class="btn btn-light" disabled="disabled">
+                            <button id="delete-service" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-trash-alt mr-2"></i>
                                 <?= lang('delete') ?>
                             </button>
@@ -88,7 +88,7 @@
                                 <i class="far fa-check-square mr-2"></i>
                                 <?= lang('save') ?>
                             </button>
-                            <button id="cancel-service" class="btn btn-light">
+                            <button id="cancel-service" class="btn btn-outline-secondary">
                                 <i class="fas fa-ban mr-2"></i>
                                 <?= lang('cancel') ?>
                             </button>
@@ -171,10 +171,10 @@
 
                             <span class="input-group-addon">
                         <div>
-                            <button class="filter btn btn-light" type="submit" title="<?= lang('filter') ?>">
+                            <button class="filter btn btn-outline-secondary" type="submit" title="<?= lang('filter') ?>">
                                 <i class="fas fa-search"></i>
                             </button>
-                            <button class="clear btn btn-light" type="button" title="<?= lang('clear') ?>">
+                            <button class="clear btn btn-outline-secondary" type="button" title="<?= lang('clear') ?>">
                                 <i class="fas fa-redo-alt"></i>
                             </button>
                         </div>
@@ -193,11 +193,11 @@
                                 <i class="far fa-plus-square mr-2"></i>
                                 <?= lang('add') ?>
                             </button>
-                            <button id="edit-category" class="btn btn-light" disabled="disabled">
+                            <button id="edit-category" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-edit mr-2"></i>
                                 <?= lang('edit') ?>
                             </button>
-                            <button id="delete-category" class="btn btn-light" disabled="disabled">
+                            <button id="delete-category" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-trash-alt mr-2"></i>
                                 <?= lang('delete') ?>
                             </button>
@@ -208,7 +208,7 @@
                                 <i class="far fa-check-square mr-2"></i>
                                 <?= lang('save') ?>
                             </button>
-                            <button id="cancel-category" class="btn btn-light">
+                            <button id="cancel-category" class="btn btn-outline-secondary">
                                 <i class="fas fa-ban mr-2"></i>
                                 <?= lang('cancel') ?>
                             </button>
diff --git a/application/views/backend/users.php b/application/views/backend/users.php
index be904d0f..fce4f278 100755
--- a/application/views/backend/users.php
+++ b/application/views/backend/users.php
@@ -67,10 +67,10 @@
 
                             <span class="input-group-addon">
                         <div>
-                            <button class="filter btn btn-light" type="submit" title="<?= lang('filter') ?>">
+                            <button class="filter btn btn-outline-secondary" type="submit" title="<?= lang('filter') ?>">
                                 <i class="fas fa-search"></i>
                             </button>
-                            <button class="clear btn btn-light" type="button" title="<?= lang('clear') ?>">
+                            <button class="clear btn btn-outline-secondary" type="button" title="<?= lang('clear') ?>">
                                 <i class="fas fa-redo-alt"></i>
                             </button>
                         </div>
@@ -89,11 +89,11 @@
                                 <i class="far fa-plus-square mr-2"></i>
                                 <?= lang('add') ?>
                             </button>
-                            <button id="edit-provider" class="btn btn-light" disabled="disabled">
+                            <button id="edit-provider" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-edit mr-2"></i>
                                 <?= lang('edit') ?>
                             </button>
-                            <button id="delete-provider" class="btn btn-light" disabled="disabled">
+                            <button id="delete-provider" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-trash-alt mr-2"></i>
                                 <?= lang('delete') ?>
                             </button>
@@ -104,7 +104,7 @@
                                 <i class="far fa-check-square mr-2"></i>
                                 <?= lang('save') ?>
                             </button>
-                            <button id="cancel-provider" class="btn btn-light">
+                            <button id="cancel-provider" class="btn btn-outline-secondary">
                                 <i class="fas fa-ban mr-2"></i>
                                 <?= lang('cancel') ?>
                             </button>
@@ -333,10 +333,10 @@
 
                             <span class="input-group-addon">
                         <div>
-                            <button class="filter btn btn-light" type="submit" title="<?= lang('filter') ?>">
+                            <button class="filter btn btn-outline-secondary" type="submit" title="<?= lang('filter') ?>">
                                 <i class="fas fa-search"></i>
                             </button>
-                            <button class="clear btn btn-light" type="button" title="<?= lang('clear') ?>">
+                            <button class="clear btn btn-outline-secondary" type="button" title="<?= lang('clear') ?>">
                                 <i class="fas fa-redo-alt"></i>
                             </button>
                         </div>
@@ -356,11 +356,11 @@
                                 <i class="far fa-plus-square mr-2"></i>
                                 <?= lang('add') ?>
                             </button>
-                            <button id="edit-secretary" class="btn btn-light" disabled="disabled">
+                            <button id="edit-secretary" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-edit mr-2"></i>
                                 <?= lang('edit') ?>
                             </button>
-                            <button id="delete-secretary" class="btn btn-light" disabled="disabled">
+                            <button id="delete-secretary" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-trash-alt mr-2"></i>
                                 <?= lang('delete') ?>
                             </button>
@@ -371,7 +371,7 @@
                                 <i class="far fa-check-square mr-2"></i>
                                 <?= lang('save') ?>
                             </button>
-                            <button id="cancel-secretary" class="btn btn-light">
+                            <button id="cancel-secretary" class="btn btn-outline-secondary">
                                 <i class="fas fa-ban mr-2"></i>
                                 <?= lang('cancel') ?>
                             </button>
@@ -501,10 +501,10 @@
 
                             <span class="input-group-addon">
                         <div>
-                            <button class="filter btn btn-light" type="submit" title="<?= lang('filter') ?>">
+                            <button class="filter btn btn-outline-secondary" type="submit" title="<?= lang('filter') ?>">
                                 <i class="fas fa-search"></i>
                             </button>
-                            <button class="clear btn btn-light" type="button" title="<?= lang('clear') ?>">
+                            <button class="clear btn btn-outline-secondary" type="button" title="<?= lang('clear') ?>">
                                 <i class="fas fa-redo-alt"></i>
                             </button>
                         </div>
@@ -524,11 +524,11 @@
                                 <i class="far fa-plus-square mr-2"></i>
                                 <?= lang('add') ?>
                             </button>
-                            <button id="edit-admin" class="btn btn-light" disabled="disabled">
+                            <button id="edit-admin" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-edit mr-2"></i>
                                 <?= lang('edit') ?>
                             </button>
-                            <button id="delete-admin" class="btn btn-light" disabled="disabled">
+                            <button id="delete-admin" class="btn btn-outline-secondary" disabled="disabled">
                                 <i class="far fa-trash-alt mr-2"></i>
                                 <?= lang('delete') ?>
                             </button>
@@ -539,7 +539,7 @@
                                 <i class="far fa-check-square mr-2"></i>
                                 <?= lang('save') ?>
                             </button>
-                            <button id="cancel-admin" class="btn btn-light">
+                            <button id="cancel-admin" class="btn btn-outline-secondary">
                                 <i class="fas fa-ban mr-2"></i>
                                 <?= lang('cancel') ?>
                             </button>
diff --git a/application/views/general/error404.php b/application/views/general/error404.php
index e1895a63..9d442691 100644
--- a/application/views/general/error404.php
+++ b/application/views/general/error404.php
@@ -39,7 +39,7 @@
             <?= lang('book_appointment_title') ?>
         </a>
 
-        <a href="<?= site_url('backend') ?>" class="btn btn-light btn-large">
+        <a href="<?= site_url('backend') ?>" class="btn btn-outline-secondary btn-large">
             <i class="fas fa-wrench mr-2"></i>
             <?= lang('backend_section') ?>
         </a>
diff --git a/application/views/general/update.php b/application/views/general/update.php
index 854bded0..34f88b1b 100644
--- a/application/views/general/update.php
+++ b/application/views/general/update.php
@@ -45,7 +45,7 @@
         <?php endif; ?>
 
         <div>
-            <a href="<?= site_url('backend') ?>" class="btn btn-light btn-large">
+            <a href="<?= site_url('backend') ?>" class="btn btn-outline-secondary btn-large">
                 <i class="fas fa-wrench mr-2"></i>
                 <?= lang('backend_section') ?>
             </a>
diff --git a/application/views/user/logout.php b/application/views/user/logout.php
index d7ecc117..d0e39dc9 100644
--- a/application/views/user/logout.php
+++ b/application/views/user/logout.php
@@ -37,7 +37,7 @@
             <?= lang('book_appointment_title') ?>
         </a>
 
-        <a href="<?= site_url('backend') ?>" class="btn btn-light btn-large">
+        <a href="<?= site_url('backend') ?>" class="btn btn-outline-secondary btn-large">
             <i class="fas fa-wrench mr-2"></i>
             <?= lang('backend_section') ?>
         </a>
diff --git a/assets/js/backend.js b/assets/js/backend.js
index 0653122e..311c55af 100644
--- a/assets/js/backend.js
+++ b/assets/js/backend.js
@@ -139,7 +139,7 @@ window.Backend = window.Backend || {};
 
         actions.forEach(function(action) {
             $('<button/>', {
-                'class': 'btn btn-light btn-xs',
+                'class': 'btn btn-outline-secondary btn-xs',
                 'text': action.label,
                 'on': {
                     'click': action.function
diff --git a/assets/js/backend_calendar_table_view.js b/assets/js/backend_calendar_table_view.js
index 89a10c15..84bdaadf 100755
--- a/assets/js/backend_calendar_table_view.js
+++ b/assets/js/backend_calendar_table_view.js
@@ -317,7 +317,7 @@ window.BackendCalendarTableView = window.BackendCalendarTableView || {};
             .appendTo('#calendar');
 
         $('<button/>', {
-            'class': 'btn btn-xs btn-light previous mr-2',
+            'class': 'btn btn-xs btn-outline-secondary previous mr-2',
             'html': [
                 $('<span/>', {
                     'class': 'fas fa-chevron-left'
@@ -334,7 +334,7 @@ window.BackendCalendarTableView = window.BackendCalendarTableView || {};
             .appendTo($calendarHeader);
 
         $('<button/>', {
-            'class': 'btn btn-xs btn-light next',
+            'class': 'btn btn-xs btn-outline-secondary next',
             'html': [
                 $('<span/>', {
                     'class': 'fas fa-chevron-right'
@@ -1095,7 +1095,7 @@ window.BackendCalendarTableView = window.BackendCalendarTableView || {};
                                 ]
                             }),
                             $('<button/>', {
-                                'class': 'close-popover btn btn-light',
+                                'class': 'close-popover btn btn-outline-secondary',
                                 'html': [
                                     $('<i/>', {
                                         'class': 'fas fa-ban mr-2'
@@ -1180,7 +1180,7 @@ window.BackendCalendarTableView = window.BackendCalendarTableView || {};
                                 ]
                             }),
                             $('<button/>', {
-                                'class': 'close-popover btn btn-light',
+                                'class': 'close-popover btn btn-outline-secondary',
                                 'html': [
                                     $('<i/>', {
                                         'class': 'fas fa-ban mr-2'
@@ -1306,7 +1306,7 @@ window.BackendCalendarTableView = window.BackendCalendarTableView || {};
                                 ]
                             }),
                             $('<button/>', {
-                                'class': 'close-popover btn btn-light',
+                                'class': 'close-popover btn btn-outline-secondary',
                                 'html': [
                                     $('<i/>', {
                                         'class': 'fas fa-ban mr-2'
diff --git a/assets/js/backend_categories_helper.js b/assets/js/backend_categories_helper.js
index 647f9262..4ac5a3ee 100644
--- a/assets/js/backend_categories_helper.js
+++ b/assets/js/backend_categories_helper.js
@@ -194,7 +194,7 @@
                 } else if (response.length === this.filterLimit) {
                     $('<button/>', {
                         'type': 'button',
-                        'class': 'btn btn-block btn-light load-more text-center',
+                        'class': 'btn btn-block btn-outline-secondary load-more text-center',
                         'text': EALang.load_more,
                         'click': function () {
                             this.filterLimit += 20;
diff --git a/assets/js/backend_customers_helper.js b/assets/js/backend_customers_helper.js
index bc894f51..91845e57 100644
--- a/assets/js/backend_customers_helper.js
+++ b/assets/js/backend_customers_helper.js
@@ -398,7 +398,7 @@
                 } else if (response.length === this.filterLimit) {
                     $('<button/>', {
                         'type': 'button',
-                        'class': 'btn btn-block btn-light load-more text-center',
+                        'class': 'btn btn-block btn-outline-secondary load-more text-center',
                         'text': EALang.load_more,
                         'click': function () {
                             this.filterLimit += 20;
diff --git a/assets/js/backend_services_helper.js b/assets/js/backend_services_helper.js
index a92b9d03..a099e0d4 100644
--- a/assets/js/backend_services_helper.js
+++ b/assets/js/backend_services_helper.js
@@ -352,7 +352,7 @@
                 } else if (response.length === this.filterLimit) {
                     $('<button/>', {
                         'type': 'button',
-                        'class': 'btn btn-block btn-light load-more text-center',
+                        'class': 'btn btn-block btn-outline-secondary load-more text-center',
                         'text': EALang.load_more,
                         'click': function () {
                             this.filterLimit += 20;
diff --git a/assets/js/backend_users_admins.js b/assets/js/backend_users_admins.js
index ee1a180a..1833f4f0 100644
--- a/assets/js/backend_users_admins.js
+++ b/assets/js/backend_users_admins.js
@@ -366,7 +366,7 @@
                 } else if (response.length === this.filterLimit) {
                     $('<button/>', {
                         'type': 'button',
-                        'class': 'btn btn-block btn-light load-more text-center',
+                        'class': 'btn btn-block btn-outline-secondary load-more text-center',
                         'text': EALang.load_more,
                         'click': function () {
                             this.filterLimit += 20;
diff --git a/assets/js/backend_users_providers.js b/assets/js/backend_users_providers.js
index f15746b1..414adb92 100755
--- a/assets/js/backend_users_providers.js
+++ b/assets/js/backend_users_providers.js
@@ -471,7 +471,7 @@
                 } else if (response.length === this.filterLimit) {
                     $('<button/>', {
                         'type': 'button',
-                        'class': 'btn btn-block btn-light load-more text-center',
+                        'class': 'btn btn-block btn-outline-secondary load-more text-center',
                         'text': EALang.load_more,
                         'click': function () {
                             this.filterLimit += 20;
diff --git a/assets/js/backend_users_secretaries.js b/assets/js/backend_users_secretaries.js
index 377d903c..82b8e053 100644
--- a/assets/js/backend_users_secretaries.js
+++ b/assets/js/backend_users_secretaries.js
@@ -393,7 +393,7 @@
                 } else if (response.length === this.filterLimit) {
                     $('<button/>', {
                         'type': 'button',
-                        'class': 'btn btn-block btn-light load-more text-center',
+                        'class': 'btn btn-block btn-outline-secondary load-more text-center',
                         'text': EALang.load_more,
                         'click': function () {
                             this.filterLimit += 20;
diff --git a/assets/js/general_functions.js b/assets/js/general_functions.js
index 8e82848a..4c7deb18 100755
--- a/assets/js/general_functions.js
+++ b/assets/js/general_functions.js
@@ -80,7 +80,7 @@ window.GeneralFunctions = window.GeneralFunctions || {};
         });
 
         $('#message-box').dialog('open');
-        $('.ui-dialog .ui-dialog-buttonset button').addClass('btn btn-light');
+        $('.ui-dialog .ui-dialog-buttonset button').addClass('btn btn-outline-secondary');
         $('#message-box .ui-dialog-titlebar-close').hide();
     };
 
diff --git a/assets/js/working_plan.js b/assets/js/working_plan.js
index 2a5adfe4..ecb7c56f 100755
--- a/assets/js/working_plan.js
+++ b/assets/js/working_plan.js
@@ -131,7 +131,7 @@
                                 'html': [
                                     $('<button/>', {
                                         'type': 'button',
-                                        'class': 'btn btn-light btn-sm edit-break',
+                                        'class': 'btn btn-outline-secondary btn-sm edit-break',
                                         'title': EALang.edit,
                                         'html': [
                                             $('<span/>', {
@@ -141,7 +141,7 @@
                                     }),
                                     $('<button/>', {
                                         'type': 'button',
-                                        'class': 'btn btn-light btn-sm delete-break',
+                                        'class': 'btn btn-outline-secondary btn-sm delete-break',
                                         'title': EALang.delete,
                                         'html': [
                                             $('<span/>', {
@@ -151,7 +151,7 @@
                                     }),
                                     $('<button/>', {
                                         'type': 'button',
-                                        'class': 'btn btn-light btn-sm save-break d-none',
+                                        'class': 'btn btn-outline-secondary btn-sm save-break d-none',
                                         'title': EALang.save,
                                         'html': [
                                             $('<span/>', {
@@ -161,7 +161,7 @@
                                     }),
                                     $('<button/>', {
                                         'type': 'button',
-                                        'class': 'btn btn-light btn-sm cancel-break d-none',
+                                        'class': 'btn btn-outline-secondary btn-sm cancel-break d-none',
                                         'title': EALang.cancel,
                                         'html': [
                                             $('<span/>', {
@@ -221,7 +221,7 @@
                             'html': [
                                 $('<button/>', {
                                     'type': 'button',
-                                    'class': 'btn btn-light btn-sm edit-custom-availability-period',
+                                    'class': 'btn btn-outline-secondary btn-sm edit-custom-availability-period',
                                     'title': EALang.edit,
                                     'html': [
                                         $('<span/>', {
@@ -231,7 +231,7 @@
                                 }),
                                 $('<button/>', {
                                     'type': 'button',
-                                    'class': 'btn btn-light btn-sm delete-custom-availability-period',
+                                    'class': 'btn btn-outline-secondary btn-sm delete-custom-availability-period',
                                     'title': EALang.delete,
                                     'html': [
                                         $('<span/>', {
@@ -241,7 +241,7 @@
                                 }),
                                 $('<button/>', {
                                     'type': 'button',
-                                    'class': 'btn btn-light btn-sm save-custom-availability-period d-none',
+                                    'class': 'btn btn-outline-secondary btn-sm save-custom-availability-period d-none',
                                     'title': EALang.save,
                                     'html': [
                                         $('<span/>', {
@@ -251,7 +251,7 @@
                                 }),
                                 $('<button/>', {
                                     'type': 'button',
-                                    'class': 'btn btn-light btn-sm cancel-custom-availability-period d-none',
+                                    'class': 'btn btn-outline-secondary btn-sm cancel-custom-availability-period d-none',
                                     'title': EALang.cancel,
                                     'html': [
                                         $('<span/>', {
@@ -406,7 +406,7 @@
                         'html': [
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm edit-break',
+                                'class': 'btn btn-outline-secondary btn-sm edit-break',
                                 'title': EALang.edit,
                                 'html': [
                                     $('<span/>', {
@@ -416,7 +416,7 @@
                             }),
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm delete-break',
+                                'class': 'btn btn-outline-secondary btn-sm delete-break',
                                 'title': EALang.delete,
                                 'html': [
                                     $('<span/>', {
@@ -426,7 +426,7 @@
                             }),
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm save-break d-none',
+                                'class': 'btn btn-outline-secondary btn-sm save-break d-none',
                                 'title': EALang.save,
                                 'html': [
                                     $('<span/>', {
@@ -436,7 +436,7 @@
                             }),
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm cancel-break d-none',
+                                'class': 'btn btn-outline-secondary btn-sm cancel-break d-none',
                                 'title': EALang.cancel,
                                 'html': [
                                     $('<span/>', {
@@ -580,7 +580,7 @@
                         'html': [
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm edit-custom-availability-period',
+                                'class': 'btn btn-outline-secondary btn-sm edit-custom-availability-period',
                                 'title': EALang.edit,
                                 'html': [
                                     $('<span/>', {
@@ -590,7 +590,7 @@
                             }),
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm delete-custom-availability-period',
+                                'class': 'btn btn-outline-secondary btn-sm delete-custom-availability-period',
                                 'title': EALang.delete,
                                 'html': [
                                     $('<span/>', {
@@ -600,7 +600,7 @@
                             }),
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm save-custom-availability-period d-none',
+                                'class': 'btn btn-outline-secondary btn-sm save-custom-availability-period d-none',
                                 'title': EALang.save,
                                 'html': [
                                     $('<span/>', {
@@ -610,7 +610,7 @@
                             }),
                             $('<button/>', {
                                 'type': 'button',
-                                'class': 'btn btn-light btn-sm cancel-custom-availability-period d-none',
+                                'class': 'btn btn-outline-secondary btn-sm cancel-custom-availability-period d-none',
                                 'title': EALang.cancel,
                                 'html': [
                                     $('<span/>', {