diff --git a/modules/gtk/gtk.mustache b/modules/gtk/gtk.mustache
index b424d214..d29c42c4 100644
--- a/modules/gtk/gtk.mustache
+++ b/modules/gtk/gtk.mustache
@@ -19,7 +19,7 @@
 @define-color view_fg_color #{{base05-hex}};
 @define-color headerbar_bg_color #{{base01-hex}};
 @define-color headerbar_fg_color #{{base05-hex}};
-@define-color headerbar_border_color #{{base01-hex}}cc;
+@define-color headerbar_border_color rgba({{base01-dec-r}}, {{base01-dec-g}}, {{base01-dec-b}}, 0.7);
 @define-color headerbar_backdrop_color @window_bg_color;
 @define-color headerbar_shade_color rgba(0, 0, 0, 0.07);
 @define-color card_bg_color #{{base01-hex}};