diff --git a/src/main/gtk-3.0/gtk-dark.css b/src/main/gtk-3.0/gtk-dark.css
index 365596c0..7e85fa86 100644
--- a/src/main/gtk-3.0/gtk-dark.css
+++ b/src/main/gtk-3.0/gtk-dark.css
@@ -5378,42 +5378,52 @@ popover.emoji-completion .emoji:hover {
   background: none;
 }
 
-.nautilus-window.background.csd .nautilus-list-view {
+.nautilus-window.background.csd.unified notebook {
+  border-radius: 0;
+}
+
+.nautilus-window.background.csd:not(.unified) .nautilus-list-view {
   background-color: transparent;
   border-bottom-right-radius: 12px;
 }
 
-.nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected), .nautilus-window.background.csd .nautilus-list-view window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow .nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), .nautilus-window.background.csd .nautilus-list-view filechooser stack.view scrolledwindow treeview.view:not(:hover):not(:active):not(:selected), filechooser stack.view scrolledwindow .nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected) {
+.nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected), .nautilus-window.background.csd:not(.unified) .nautilus-list-view window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow .nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), .nautilus-window.background.csd:not(.unified) .nautilus-list-view filechooser stack.view scrolledwindow treeview.view:not(:hover):not(:active):not(:selected), filechooser stack.view scrolledwindow .nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected) {
   background-color: transparent;
-  border-radius: 0;
 }
 
-.nautilus-window.background.csd notebook {
+.nautilus-window.background.csd:not(.unified) notebook {
   background-color: #2C2C2C;
-  border-radius: 0;
+  border-radius: 0 0 12px 12px;
 }
 
-.nautilus-window.background.csd notebook > stack {
-  background-color: #2C2C2C;
-}
-
-.nautilus-window.background.csd notebook scrolledwindow > .view:not(:selected):not(:hover):not(:checked), .nautilus-window.background.csd notebook window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked):not(.progressbar):not(.trough), .nautilus-window.background.csd notebook filechooser stack.view scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked), filechooser stack.view .nautilus-window.background.csd notebook scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked) {
+.nautilus-window.background.csd:not(.unified) notebook > stack {
   background-color: transparent;
 }
 
-.nautilus-window.background.csd notebook placesview > stack > frame > scrolledwindow > viewport > list {
+.nautilus-window.background.csd:not(.unified) notebook scrolledwindow > .view:not(:selected):not(:hover):not(:checked), .nautilus-window.background.csd:not(.unified) notebook window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked):not(.progressbar):not(.trough), .nautilus-window.background.csd:not(.unified) notebook filechooser stack.view scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked), filechooser stack.view .nautilus-window.background.csd:not(.unified) notebook scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked) {
   background-color: transparent;
 }
 
-.nautilus-window.background.csd notebook placesview > actionbar {
+.nautilus-window.background.csd:not(.unified) notebook placesview > stack > frame > scrolledwindow > viewport > list {
+  background-color: transparent;
+}
+
+.nautilus-window.background.csd:not(.unified) notebook placesview > actionbar {
   background-color: transparent;
   border-radius: 0 0 12px 12px;
 }
 
-.nautilus-window.background.csd notebook placesview > actionbar > revealer > box {
+.nautilus-window.background.csd:not(.unified) notebook placesview > actionbar > revealer > box {
   background-color: transparent;
 }
 
+.nautilus-window.background.csd:not(.unified) paned > separator {
+  min-width: 12px;
+  box-shadow: 12px 0 #2C2C2C;
+  background-color: #2C2C2C;
+  background-image: image(#3e3e3e);
+}
+
 .nautilus-window.maximized, .nautilus-window.maximized placessidebar {
   border-radius: 0;
 }
diff --git a/src/main/gtk-3.0/gtk-light.css b/src/main/gtk-3.0/gtk-light.css
index 8fd58f12..cb7860b9 100644
--- a/src/main/gtk-3.0/gtk-light.css
+++ b/src/main/gtk-3.0/gtk-light.css
@@ -5378,42 +5378,52 @@ popover.emoji-completion .emoji:hover {
   background: none;
 }
 
-.nautilus-window.background.csd .nautilus-list-view {
+.nautilus-window.background.csd.unified notebook {
+  border-radius: 0;
+}
+
+.nautilus-window.background.csd:not(.unified) .nautilus-list-view {
   background-color: transparent;
   border-bottom-right-radius: 12px;
 }
 
-.nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected), .nautilus-window.background.csd .nautilus-list-view window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow .nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), .nautilus-window.background.csd .nautilus-list-view filechooser stack.view scrolledwindow treeview.view:not(:hover):not(:active):not(:selected), filechooser stack.view scrolledwindow .nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected) {
+.nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected), .nautilus-window.background.csd:not(.unified) .nautilus-list-view window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow .nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), .nautilus-window.background.csd:not(.unified) .nautilus-list-view filechooser stack.view scrolledwindow treeview.view:not(:hover):not(:active):not(:selected), filechooser stack.view scrolledwindow .nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected) {
   background-color: transparent;
-  border-radius: 0;
 }
 
-.nautilus-window.background.csd notebook {
+.nautilus-window.background.csd:not(.unified) notebook {
   background-color: #FFFFFF;
-  border-radius: 0;
+  border-radius: 0 0 12px 12px;
 }
 
-.nautilus-window.background.csd notebook > stack {
-  background-color: #FFFFFF;
-}
-
-.nautilus-window.background.csd notebook scrolledwindow > .view:not(:selected):not(:hover):not(:checked), .nautilus-window.background.csd notebook window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked):not(.progressbar):not(.trough), .nautilus-window.background.csd notebook filechooser stack.view scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked), filechooser stack.view .nautilus-window.background.csd notebook scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked) {
+.nautilus-window.background.csd:not(.unified) notebook > stack {
   background-color: transparent;
 }
 
-.nautilus-window.background.csd notebook placesview > stack > frame > scrolledwindow > viewport > list {
+.nautilus-window.background.csd:not(.unified) notebook scrolledwindow > .view:not(:selected):not(:hover):not(:checked), .nautilus-window.background.csd:not(.unified) notebook window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked):not(.progressbar):not(.trough), .nautilus-window.background.csd:not(.unified) notebook filechooser stack.view scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked), filechooser stack.view .nautilus-window.background.csd:not(.unified) notebook scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked) {
   background-color: transparent;
 }
 
-.nautilus-window.background.csd notebook placesview > actionbar {
+.nautilus-window.background.csd:not(.unified) notebook placesview > stack > frame > scrolledwindow > viewport > list {
+  background-color: transparent;
+}
+
+.nautilus-window.background.csd:not(.unified) notebook placesview > actionbar {
   background-color: transparent;
   border-radius: 0 0 12px 12px;
 }
 
-.nautilus-window.background.csd notebook placesview > actionbar > revealer > box {
+.nautilus-window.background.csd:not(.unified) notebook placesview > actionbar > revealer > box {
   background-color: transparent;
 }
 
+.nautilus-window.background.csd:not(.unified) paned > separator {
+  min-width: 12px;
+  box-shadow: 12px 0 #FFFFFF;
+  background-color: #FFFFFF;
+  background-image: image(gainsboro);
+}
+
 .nautilus-window.maximized, .nautilus-window.maximized placessidebar {
   border-radius: 0;
 }
diff --git a/src/main/gtk-3.0/gtk.css b/src/main/gtk-3.0/gtk.css
index f8a3e536..71c90b5c 100644
--- a/src/main/gtk-3.0/gtk.css
+++ b/src/main/gtk-3.0/gtk.css
@@ -5387,42 +5387,52 @@ popover.emoji-completion .emoji:hover {
   background: none;
 }
 
-.nautilus-window.background.csd .nautilus-list-view {
+.nautilus-window.background.csd.unified notebook {
+  border-radius: 0;
+}
+
+.nautilus-window.background.csd:not(.unified) .nautilus-list-view {
   background-color: transparent;
   border-bottom-right-radius: 12px;
 }
 
-.nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected), .nautilus-window.background.csd .nautilus-list-view window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow .nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), .nautilus-window.background.csd .nautilus-list-view filechooser stack.view scrolledwindow treeview.view:not(:hover):not(:active):not(:selected), filechooser stack.view scrolledwindow .nautilus-window.background.csd .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected) {
+.nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected), .nautilus-window.background.csd:not(.unified) .nautilus-list-view window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow .nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected):not(.progressbar):not(.trough), .nautilus-window.background.csd:not(.unified) .nautilus-list-view filechooser stack.view scrolledwindow treeview.view:not(:hover):not(:active):not(:selected), filechooser stack.view scrolledwindow .nautilus-window.background.csd:not(.unified) .nautilus-list-view treeview.view:not(:hover):not(:active):not(:selected) {
   background-color: transparent;
-  border-radius: 0;
 }
 
-.nautilus-window.background.csd notebook {
+.nautilus-window.background.csd:not(.unified) notebook {
   background-color: #FFFFFF;
-  border-radius: 0;
+  border-radius: 0 0 12px 12px;
 }
 
-.nautilus-window.background.csd notebook > stack {
-  background-color: #FFFFFF;
-}
-
-.nautilus-window.background.csd notebook scrolledwindow > .view:not(:selected):not(:hover):not(:checked), .nautilus-window.background.csd notebook window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked):not(.progressbar):not(.trough), .nautilus-window.background.csd notebook filechooser stack.view scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked), filechooser stack.view .nautilus-window.background.csd notebook scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked) {
+.nautilus-window.background.csd:not(.unified) notebook > stack {
   background-color: transparent;
 }
 
-.nautilus-window.background.csd notebook placesview > stack > frame > scrolledwindow > viewport > list {
+.nautilus-window.background.csd:not(.unified) notebook scrolledwindow > .view:not(:selected):not(:hover):not(:checked), .nautilus-window.background.csd:not(.unified) notebook window#gnome-system-monitor.background.csd > box.vertical > stack > box.vertical > scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked):not(.progressbar):not(.trough), .nautilus-window.background.csd:not(.unified) notebook filechooser stack.view scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked), filechooser stack.view .nautilus-window.background.csd:not(.unified) notebook scrolledwindow > treeview.view:not(:selected):not(:hover):not(:checked) {
   background-color: transparent;
 }
 
-.nautilus-window.background.csd notebook placesview > actionbar {
+.nautilus-window.background.csd:not(.unified) notebook placesview > stack > frame > scrolledwindow > viewport > list {
+  background-color: transparent;
+}
+
+.nautilus-window.background.csd:not(.unified) notebook placesview > actionbar {
   background-color: transparent;
   border-radius: 0 0 12px 12px;
 }
 
-.nautilus-window.background.csd notebook placesview > actionbar > revealer > box {
+.nautilus-window.background.csd:not(.unified) notebook placesview > actionbar > revealer > box {
   background-color: transparent;
 }
 
+.nautilus-window.background.csd:not(.unified) paned > separator {
+  min-width: 12px;
+  box-shadow: 12px 0 #FFFFFF;
+  background-color: #FFFFFF;
+  background-image: image(gainsboro);
+}
+
 .nautilus-window.maximized, .nautilus-window.maximized placessidebar {
   border-radius: 0;
 }
diff --git a/src/sass/gtk/apps/_gnome-3.0.scss b/src/sass/gtk/apps/_gnome-3.0.scss
index 959af77f..2588b4a9 100644
--- a/src/sass/gtk/apps/_gnome-3.0.scss
+++ b/src/sass/gtk/apps/_gnome-3.0.scss
@@ -6,10 +6,12 @@
 // hard-coded css:
 // https://gitlab.gnome.org/GNOME/nautilus/blob/master/src/resources/css/nautilus.css
 
+$nautilus: if($variant == 'light' and $topbar == 'dark', $base-alt, $titlebar);
+
 .nautilus-window {
   &.background.csd {
     border-radius: 0 0 $window-radius $window-radius;
-    background-color: if($variant == 'light' and $topbar == 'dark', $base-alt, $titlebar);
+    background-color: $nautilus;
 
     &:backdrop { background-color: $base; }
 
@@ -24,37 +26,50 @@
       }
     }
 
-    .nautilus-list-view {
-      background-color: transparent;
-      border-bottom-right-radius: $window-radius;
-
-      treeview.view:not(:hover):not(:active):not(:selected) {
-        background-color: transparent;
+    &.unified {
+      notebook {
         border-radius: 0;
       }
     }
 
-    notebook {
-      background-color: $base;
-      border-radius: 0;
-
-      > stack {
-        background-color: $base;
-        // border-radius: 0 0 $window-radius $window-radius;
-      }
-
-      scrolledwindow > .view:not(:selected):not(:hover):not(:checked) {
+    &:not(.unified) {
+      .nautilus-list-view {
         background-color: transparent;
+        border-bottom-right-radius: $window-radius;
+
+        treeview.view:not(:hover):not(:active):not(:selected) {
+          background-color: transparent;
+        }
       }
 
-      placesview {
-        > stack > frame > scrolledwindow > viewport > list { background-color: transparent; }
-        > actionbar {
-          background-color: transparent;
-          border-radius: 0 0 $window-radius $window-radius;
+      notebook {
+        background-color: $base;
+        border-radius: 0 0 $window-radius $window-radius;
 
-          > revealer > box { background-color: transparent; }
+        > stack {
+          background-color: transparent;
         }
+
+        scrolledwindow > .view:not(:selected):not(:hover):not(:checked) {
+          background-color: transparent;
+        }
+
+        placesview {
+          > stack > frame > scrolledwindow > viewport > list { background-color: transparent; }
+          > actionbar {
+            background-color: transparent;
+            border-radius: 0 0 $window-radius $window-radius;
+
+            > revealer > box { background-color: transparent; }
+          }
+        }
+      }
+
+      paned > separator { // Use paned separator to hide stack border-bottom-left-radius
+        min-width: $window-radius;
+        box-shadow: $window-radius 0 $base;
+        background-color: $base;
+        background-image: image(if($variant == 'light', mix(black, $nautilus, 12%), mix(white, $nautilus, 12%)));
       }
     }
   }