diff --git a/gtk/theme/Adwaita/gtk-contained-dark.css b/gtk/theme/Adwaita/gtk-contained-dark.css
index 32ea468f42..506cfa02b4 100644
--- a/gtk/theme/Adwaita/gtk-contained-dark.css
+++ b/gtk/theme/Adwaita/gtk-contained-dark.css
@@ -686,6 +686,10 @@ window.csd > .titlebar:not(headerbar) { padding: 0; background-color: transparen
 
 .titlebar:not(headerbar) > separator { background-color: #1b1f20; }
 
+window.devel headerbar { background: transparent -gtk-icontheme("system-run-symbolic") 80% 0/128px 128px no-repeat, linear-gradient(to left, #2a4b6c 8%, #33393b 25%); color: rgba(238, 238, 236, 0.1); }
+
+window.devel headerbar label { color: #eeeeec; }
+
 /************ Pathbars * */
 .path-bar button.text-button, .path-bar button.image-button, .path-bar button { padding-left: 4px; padding-right: 4px; }
 
diff --git a/gtk/theme/Adwaita/gtk-contained.css b/gtk/theme/Adwaita/gtk-contained.css
index 1126820c01..646e7b9622 100644
--- a/gtk/theme/Adwaita/gtk-contained.css
+++ b/gtk/theme/Adwaita/gtk-contained.css
@@ -694,6 +694,10 @@ window.csd > .titlebar:not(headerbar) { padding: 0; background-color: transparen
 
 .titlebar:not(headerbar) > separator { background-color: #b6b6b3; }
 
+window.devel headerbar { background: transparent -gtk-icontheme("system-run-symbolic") 80% 0/128px 128px no-repeat, linear-gradient(to left, #99bce0 8%, #e8e8e7 25%); color: rgba(46, 52, 54, 0.1); }
+
+window.devel headerbar label { color: #2e3436; }
+
 /************ Pathbars * */
 .path-bar button.text-button, .path-bar button.image-button, .path-bar button { padding-left: 4px; padding-right: 4px; }