diff --git a/themes/SurGubbe/gtk.css b/themes/SurGubbe/gtk.css
index 575abb3..2198ad5 100644
--- a/themes/SurGubbe/gtk.css
+++ b/themes/SurGubbe/gtk.css
@@ -14,6 +14,10 @@
 @define-color dialog_fg_color @popover_fg_color;
 @define-color card_bg_color @view_bg_color;
 @define-color card_fg_color @view_fg_color;
+@define-color sidebar_bg_color @headerbar_bg_color;
+@define-color sidebar_fg_color @window_fg_color;
+@define-color sidebar_backdrop_color @window_bg_color;
+@define-color sidebar_shade_color rgba(0,0,0,0.25);
 button.titlebutton,
 windowcontrols > button {
   color: transparent;
diff --git a/themes/wandows-ngrmadly/gtk.css b/themes/wandows-ngrmadly/gtk.css
index 5822ad6..a15de33 100644
--- a/themes/wandows-ngrmadly/gtk.css
+++ b/themes/wandows-ngrmadly/gtk.css
@@ -14,6 +14,10 @@
 @define-color dialog_fg_color @popover_fg_color;
 @define-color card_bg_color @view_bg_color;
 @define-color card_fg_color @view_fg_color;
+@define-color sidebar_bg_color @headerbar_bg_color;
+@define-color sidebar_fg_color @window_fg_color;
+@define-color sidebar_backdrop_color @window_bg_color;
+@define-color sidebar_shade_color rgba(0,0,0,0.25);
 window,
 decoration,
 decoration-overlay {