diff -r d02e1149cdb9 -r 301d6c73087a ui/gtk/headerbar.c
--- a/ui/gtk/headerbar.c	Sun Sep 22 19:47:26 2024 +0200
+++ b/ui/gtk/headerbar.c	Sun Sep 22 21:17:15 2024 +0200
@@ -118,6 +118,7 @@
 
 void ui_add_headerbar_item(GtkWidget *headerbar, GtkWidget *box, UiToolbarItem *item, UiObject *obj, enum UiToolbarPos pos) {
     GtkWidget *button = gtk_button_new_with_label(item->args.label);
+    WIDGET_ADD_CSS_CLASS(button, "flat");
     headerbar_add(headerbar, box, button, pos);
 }