diff --git a/ihatemoney/templates/forms.html b/ihatemoney/templates/forms.html
index 12cc1651..61127ce7 100644
--- a/ihatemoney/templates/forms.html
+++ b/ihatemoney/templates/forms.html
@@ -123,7 +123,7 @@
         <label class="sr-only" for="name">_("Add participant")</label>
         {{ form.name(placeholder=_("Add participant"), class="form-control") }}
         <div class="input-group-append">
-            <button class="btn btn-outline-secondary input-group-addon" type="submit">{{ _("Add") }}</button>
+            <button class="btn btn-secondary input-group-addon" type="submit">{{ _("Add") }}</button>
         </div>
     </div>
 {% endmacro %}