diff --git a/instances/templates/instances/edit_instance_volume.html b/instances/templates/instances/edit_instance_volume.html
index 525f7e93..0a849e5c 100644
--- a/instances/templates/instances/edit_instance_volume.html
+++ b/instances/templates/instances/edit_instance_volume.html
@@ -1,6 +1,6 @@
 {% load i18n %}
 {% if request.user.is_superuser %}
-    <button href="#editvol{{ id }}" type="button" class="btn btn-sm btn-secondary" data-bs-toggle="modal">{% trans "Edit" %}</button>
+    <button href="#editvol{{ id }}" type="button" class="btn btn-sm btn-outline-secondary" data-bs-toggle="modal">{% trans "Edit" %}</button>
 
     <div class="modal fade" id="editvol{{ id }}" tabindex="-1" role="dialog" aria-labelledby="editInstanceVolumeLabel{{ id }}" aria-hidden="true">
         <div class="modal-dialog">
diff --git a/instances/templates/instances/move_disk.html b/instances/templates/instances/move_disk.html
index 4bd165cb..da35abed 100644
--- a/instances/templates/instances/move_disk.html
+++ b/instances/templates/instances/move_disk.html
@@ -2,7 +2,7 @@
 {% load bootstrap_icons %}
 {% load operations %}
 {# the Move button of a disk and its dialog: another storage pool of this host #}
-<button type="button" class="btn btn-sm btn-secondary" data-bs-toggle="modal" data-bs-target="#movedisk{{ id }}" title="{% trans "Move to another pool" %}">{% trans "Move" %}</button>
+<button type="button" class="btn btn-sm btn-outline-secondary" data-bs-toggle="modal" data-bs-target="#movedisk{{ id }}" title="{% trans "Move to another pool" %}">{% trans "Move" %}</button>
 <div class="modal fade" id="movedisk{{ id }}" tabindex="-1" aria-labelledby="movedisk{{ id }}-label" aria-hidden="true">
     <div class="modal-dialog">
         <form class="modal-content text-wrap" action="{% url 'instances:move_disk' instance.id %}" method="post">
diff --git a/instances/templates/instances/settings_tab.html b/instances/templates/instances/settings_tab.html
index 534dd153..1d81bfe6 100644
--- a/instances/templates/instances/settings_tab.html
+++ b/instances/templates/instances/settings_tab.html
@@ -161,14 +161,14 @@
                                 </div>
                             </div>
                             {% if not cd.image or cd.bus == "usb" %}
-                            <button type="submit" class="btn btn-sm btn-secondary" formaction="{% url 'instances:detach_cdrom' instance.id cd.dev %}" formmethod="post"{% if instance.status != 5 and cd.bus != "scsi" and cd.bus != "usb" %} disabled{% endif %}>{% trans "Detach" %}</button>
+                            <button type="submit" class="btn btn-sm btn-outline-secondary" formaction="{% url 'instances:detach_cdrom' instance.id cd.dev %}" formmethod="post"{% if instance.status != 5 and cd.bus != "scsi" and cd.bus != "usb" %} disabled{% endif %}>{% trans "Detach" %}</button>
                             {% endif %}
                         </div>
                         {% if cd.bus == "usb" %}
                         {# libvirt has no empty USB drive: it is detached, not ejected #}
                         {% elif cd.image %}
                         <input type="hidden" name="path" value="{{ cd.path }}">
-                        <button type="submit" class="btn btn-sm btn-primary" value="{{ cd.dev }}" name="umount_iso">{% bs_icon 'eject' %} {% trans "Unmount" %}</button>
+                        <button type="submit" class="btn btn-sm btn-outline-secondary" value="{{ cd.dev }}" name="umount_iso">{% bs_icon 'eject' %} {% trans "Unmount" %}</button>
                         {% else %}
                         <label class="form-label small" for="media-{{ cd.dev }}">{% trans "ISO image" %}</label>
                         <div class="row g-2">
@@ -240,7 +240,7 @@
                                     <input type="hidden" name="dev" value="{{ disk.dev }}">
                                     <input type="hidden" name="storage" value="{{ disk.storage }}">
                                     <input type="hidden" name="name" value="{{ disk.image }}">
-                                    <button type="submit" class="btn btn-sm btn-secondary" value="{{ disk.dev }}"{% if instance.status != 5 %} disabled{% endif %} data-confirm="{% blocktrans with dev=disk.dev %}Detach {{ dev }}? Its file is kept.{% endblocktrans %}">{% trans "Detach" %}</button>
+                                    <button type="submit" class="btn btn-sm btn-outline-secondary" value="{{ disk.dev }}"{% if instance.status != 5 %} disabled{% endif %} data-confirm="{% blocktrans with dev=disk.dev %}Detach {{ dev }}? Its file is kept.{% endblocktrans %}">{% trans "Detach" %}</button>
                                 </form>
                                 <form class="d-inline" action="{% url 'instances:delete_vol' instance.id %}" method="post">
                                     {% csrf_token %}
@@ -248,7 +248,7 @@
                                     <input type="hidden" name="dev" value="{{ disk.dev }}">
                                     <input type="hidden" name="storage" value="{{ disk.storage }}">
                                     <input type="hidden" name="name" value="{{ disk.image }}">
-                                    <button type="submit" class="btn btn-sm btn-danger"{% if instance.status != 5 %} disabled{% endif %} data-confirm="{% blocktrans with dev=disk.dev %}Delete {{ dev }}? It is detached and its file and data are removed.{% endblocktrans %}">{% trans "Delete" %}</button>
+                                    <button type="submit" class="btn btn-sm btn-outline-danger"{% if instance.status != 5 %} disabled{% endif %} data-confirm="{% blocktrans with dev=disk.dev %}Delete {{ dev }}? It is detached and its file and data are removed.{% endblocktrans %}">{% trans "Delete" %}</button>
                                 </form>
                             </div>
                         </div>