Remove headerbar separators

src/gtk-3.0/gtk-dark-solid.css

@@ -1587,13 +1587,18 @@ window.csd > .titlebar:not(headerbar):backdrop {
 }
 
 .titlebar:not(headerbar) > separator {
-  background-image: linear-gradient(to bottom, #484848, #484848);
+  background-image: none;
+}
+
+.titlebar:not(headerbar) > separator:backdrop {
+  background-image: none;
+  background-color: #404040;
 }
 
 .primary-toolbar:not(.libreoffice-toolbar) separator, headerbar separator.titlebutton, .titlebar:not(headerbar) separator.titlebutton {
   min-width: 0;
   min-height: 0;
-  background: none;
+  background-color: transparent;
   border-width: 0;
   border-image: none;
 }
@@ -5598,6 +5603,9 @@ dialog.csd > headerbar.titlebar > switch {
   margin: 8px 0;
 }
 
+/************************
+  * Gnome Control Center *
+  ************************/
 box.horizontal.titlebar > headerbar > stack > box.vertical > .title {
   margin: 0;
 }

src/gtk-3.0/gtk-dark.css

@@ -1587,13 +1587,18 @@ window.csd > .titlebar:not(headerbar):backdrop {
 }
 
 .titlebar:not(headerbar) > separator {
-  background-image: linear-gradient(to bottom, #484848, #484848);
+  background-image: none;
+}
+
+.titlebar:not(headerbar) > separator:backdrop {
+  background-image: none;
+  background-color: #404040;
 }
 
 .primary-toolbar:not(.libreoffice-toolbar) separator, headerbar separator.titlebutton, .titlebar:not(headerbar) separator.titlebutton {
   min-width: 0;
   min-height: 0;
-  background: none;
+  background-color: transparent;
   border-width: 0;
   border-image: none;
 }
@@ -5598,6 +5603,9 @@ dialog.csd > headerbar.titlebar > switch {
   margin: 8px 0;
 }
 
+/************************
+  * Gnome Control Center *
+  ************************/
 box.horizontal.titlebar > headerbar > stack > box.vertical > .title {
   margin: 0;
 }

src/gtk-3.0/gtk-light-solid.css

@@ -1589,13 +1589,18 @@ window.csd > .titlebar:not(headerbar):backdrop {
 }
 
 .titlebar:not(headerbar) > separator {
-  background-image: linear-gradient(to bottom, #afafaf, #afafaf);
+  background-image: linear-gradient(0deg, #d2d2d2 0%, #e2e2e2 50%, #e9e9e9 95%, #f5f5f5 100%);
+}
+
+.titlebar:not(headerbar) > separator:backdrop {
+  background-image: none;
+  background-color: #F6F6F6;
 }
 
 .primary-toolbar:not(.libreoffice-toolbar) separator, headerbar separator.titlebutton, .titlebar:not(headerbar) separator.titlebutton {
   min-width: 0;
   min-height: 0;
-  background: none;
+  background-color: transparent;
   border-width: 0;
   border-image: none;
 }
@@ -5615,6 +5620,9 @@ dialog.csd > headerbar.titlebar > switch {
   margin: 8px 0;
 }
 
+/************************
+  * Gnome Control Center *
+  ************************/
 box.horizontal.titlebar > headerbar > stack > box.vertical > .title {
   margin: 0;
 }

src/gtk-3.0/gtk-light.css

@@ -1589,13 +1589,18 @@ window.csd > .titlebar:not(headerbar):backdrop {
 }
 
 .titlebar:not(headerbar) > separator {
-  background-image: linear-gradient(to bottom, #afafaf, #afafaf);
+  background-image: linear-gradient(0deg, #d2d2d2 0%, #e2e2e2 50%, #e9e9e9 95%, whitesmoke 100%);
+}
+
+.titlebar:not(headerbar) > separator:backdrop {
+  background-image: none;
+  background-color: #F6F6F6;
 }
 
 .primary-toolbar:not(.libreoffice-toolbar) separator, headerbar separator.titlebutton, .titlebar:not(headerbar) separator.titlebutton {
   min-width: 0;
   min-height: 0;
-  background: none;
+  background-color: transparent;
   border-width: 0;
   border-image: none;
 }
@@ -5615,6 +5620,9 @@ dialog.csd > headerbar.titlebar > switch {
   margin: 8px 0;
 }
 
+/************************
+  * Gnome Control Center *
+  ************************/
 box.horizontal.titlebar > headerbar > stack > box.vertical > .title {
   margin: 0;
 }

src/gtk-3.0/sass/_applications.scss

@@ -782,9 +782,9 @@ button.documents-favorite:active:hover {
 .tweak-titlebar-right,
 dialog.csd > headerbar.titlebar { > switch { margin: 8px 0; } }
 
-// /************************
+ /************************
-//  * Gnome-Control-Center *
+  * Gnome Control Center *
-//  ************************/
+  ************************/
 
 // users section
 

src/gtk-3.0/sass/_common.scss

@@ -1277,7 +1277,14 @@ headerbar {
     }
   }
 
-  > separator { background-image: _solid($header_border); }
+  > separator {
+    background-image: $_header_image;
+
+    &:backdrop {
+      background-image: none;
+      background-color: $header_bg_backdrop;
+    }
+  }
 
   @extend %titlebar;
 }
@@ -1285,7 +1292,7 @@ headerbar {
 %header_separator {
   min-width: 0;
   min-height: 0;
-  background: none;
+  background-color: transparent;
   border-width: 0;
   border-image: none;