diff --git a/gtk/resources/theme/Adwaita/_common.scss b/gtk/resources/theme/Adwaita/_common.scss
index d8fb84761a..e9763a9fc0 100644
--- a/gtk/resources/theme/Adwaita/_common.scss
+++ b/gtk/resources/theme/Adwaita/_common.scss
@@ -851,6 +851,9 @@ GtkComboBox {
   }
   .header-bar-separator,
   & > GtkBox > .separator.vertical {
+    -GtkWidget-wide-separators: true;
+    -GtkWidget-separator-width: 0;
+    /*
     -GtkWidget-wide-separators: true;
     -GtkWidget-separator-width: 1px;
     border-width: 0 1px;
@@ -866,6 +869,7 @@ GtkComboBox {
                                                    0.5))
                     0 1 / 1px 1px;  //FIXME use a proper color
     }
+    */
   }
   &.selection-mode {
     color: darken($selected_bg_color, 15%);
diff --git a/gtk/resources/theme/Adwaita/gtk-contained-dark.css b/gtk/resources/theme/Adwaita/gtk-contained-dark.css
index 09f8169d4c..6c106eb42b 100644
--- a/gtk/resources/theme/Adwaita/gtk-contained-dark.css
+++ b/gtk/resources/theme/Adwaita/gtk-contained-dark.css
@@ -918,14 +918,25 @@ GtkComboBox {
   .titlebar .header-bar-separator, GtkCalendar.header .header-bar-separator, .titlebar > GtkBox > .separator.vertical, GtkCalendar.header > GtkBox > .separator.vertical,
   .header-bar .header-bar-separator,
   .header-bar > GtkBox > .separator.vertical {
+    -GtkWidget-wide-separators: true;
+    -GtkWidget-separator-width: 0;
+    /*
     -GtkWidget-wide-separators: true;
     -GtkWidget-separator-width: 1px;
     border-width: 0 1px;
-    border-image: linear-gradient(to bottom, rgba(28, 31, 31, 0), #1c1f1f 30%, #1c1f1f 70%, rgba(28, 31, 31, 0) 100%) 0 1/0 1px stretch; }
-    .titlebar .header-bar-separator:backdrop, GtkCalendar.header .header-bar-separator:backdrop, .titlebar > GtkBox > .separator.vertical:backdrop, GtkCalendar.header > GtkBox > .separator.vertical:backdrop,
-    .header-bar .header-bar-separator:backdrop,
-    .header-bar > GtkBox > .separator.vertical:backdrop {
-      border-image: linear-gradient(to bottom, rgba(30, 34, 34, 0.5)) 0 1/1px 1px; }
+    border-image: linear-gradient(to bottom,
+                                  transparentize($borders_color,1),
+                                  $borders_color 30%,
+                                  $borders_color 70%,
+                                  transparentize($borders_color,1) 100%)
+                  0 1 / 0 1px stretch; //FIXME use a proper color
+    &:backdrop {
+      border-image: linear-gradient(to bottom,
+                                    transparentize($backdrop_borders_color,
+                                                   0.5))
+                    0 1 / 1px 1px;  //FIXME use a proper color
+    }
+    */ }
   .titlebar.selection-mode, GtkCalendar.selection-mode.header,
   .header-bar.selection-mode {
     color: #14375d;
diff --git a/gtk/resources/theme/Adwaita/gtk-contained.css b/gtk/resources/theme/Adwaita/gtk-contained.css
index 31c86d69d4..2175b41e6f 100644
--- a/gtk/resources/theme/Adwaita/gtk-contained.css
+++ b/gtk/resources/theme/Adwaita/gtk-contained.css
@@ -910,14 +910,25 @@ GtkComboBox {
   .titlebar .header-bar-separator, GtkCalendar.header .header-bar-separator, .titlebar > GtkBox > .separator.vertical, GtkCalendar.header > GtkBox > .separator.vertical,
   .header-bar .header-bar-separator,
   .header-bar > GtkBox > .separator.vertical {
+    -GtkWidget-wide-separators: true;
+    -GtkWidget-separator-width: 0;
+    /*
     -GtkWidget-wide-separators: true;
     -GtkWidget-separator-width: 1px;
     border-width: 0 1px;
-    border-image: linear-gradient(to bottom, rgba(161, 161, 161, 0), #a1a1a1 30%, #a1a1a1 70%, rgba(161, 161, 161, 0) 100%) 0 1/0 1px stretch; }
-    .titlebar .header-bar-separator:backdrop, GtkCalendar.header .header-bar-separator:backdrop, .titlebar > GtkBox > .separator.vertical:backdrop, GtkCalendar.header > GtkBox > .separator.vertical:backdrop,
-    .header-bar .header-bar-separator:backdrop,
-    .header-bar > GtkBox > .separator.vertical:backdrop {
-      border-image: linear-gradient(to bottom, rgba(168, 168, 168, 0.5)) 0 1/1px 1px; }
+    border-image: linear-gradient(to bottom,
+                                  transparentize($borders_color,1),
+                                  $borders_color 30%,
+                                  $borders_color 70%,
+                                  transparentize($borders_color,1) 100%)
+                  0 1 / 0 1px stretch; //FIXME use a proper color
+    &:backdrop {
+      border-image: linear-gradient(to bottom,
+                                    transparentize($backdrop_borders_color,
+                                                   0.5))
+                    0 1 / 1px 1px;  //FIXME use a proper color
+    }
+    */ }
   .titlebar.selection-mode, GtkCalendar.selection-mode.header,
   .header-bar.selection-mode {
     color: #256ab1;