diff --git a/src/calls-contacts-box.c b/src/calls-contacts-box.c
index 6881400..e79fd37 100644
--- a/src/calls-contacts-box.c
+++ b/src/calls-contacts-box.c
@@ -77,12 +77,10 @@ adjust_style (CallsContactsBox *self, GtkWidget *widget)
 
   if (gtk_widget_get_mapped (widget)) {
     gtk_widget_set_vexpand (self->contacts_frame, TRUE);
-    gtk_style_context_add_class (gtk_widget_get_style_context (self->contacts_listbox),
-                                 "no-background");
+    gtk_widget_add_css_class (self->contacts_listbox, "no-background");
   } else {
     gtk_widget_set_vexpand (self->contacts_frame, FALSE);
-    gtk_style_context_remove_class (gtk_widget_get_style_context (self->contacts_listbox),
-                                    "no-background");
+    gtk_widget_remove_css_class (self->contacts_listbox, "no-background");
   }
 }
 
diff --git a/src/calls-contacts-row.c b/src/calls-contacts-row.c
index 0ac9b1e..6fcc5a5 100644
--- a/src/calls-contacts-row.c
+++ b/src/calls-contacts-row.c
@@ -40,7 +40,7 @@ insert_phonenumber (CallsContactsRow *self,
 
   gtk_widget_set_halign (label, GTK_ALIGN_START);
   gtk_label_set_ellipsize (GTK_LABEL (label), PANGO_ELLIPSIZE_END);
-  gtk_style_context_add_class (gtk_widget_get_style_context (label), "dim-label");
+  gtk_widget_add_css_class (label, "dim-label");
   gtk_widget_set_visible (label, TRUE);
   gtk_grid_attach (GTK_GRID (self->grid), label, 1, self->n_phonenumbers, 1, 1);