Adwaita: added a border to sidebars...

...hopefully when needed.
By default I assume a left hand side placement on ltr languages
and the opposite in rtl, for other placements left/right style
classes can be used.

gtk/theme/Adwaita/_common.scss

@@ -164,8 +164,7 @@ assistant {
   .sidebar {
     background-color: $base_color;
     border-top: 1px solid $borders_color;
-    &:dir(ltr) { border-right: 1px solid $borders_color; }
-    &:dir(rtl) { border-left: 1px solid $borders_color; }
+
     &:backdrop {
       background-color: $backdrop_base_color;
       border-color: $backdrop_borders_color;
@@ -2957,7 +2956,7 @@ printdialog {
 /**********
  * Frames *
  **********/
-frame border,
+frame > border,
 .frame {
   box-shadow: none;
   margin: 0;
@@ -3254,11 +3253,27 @@ filechooser {
  * Sidebar *
  ***********/
 .sidebar {
-  border: none;
+  border-style: none;
   background-color: mix($bg_color, $base_color, 50%);
 
+  @at-root %sidebar_left,
+  &:dir(ltr),
+  &.left,
+  &.left:dir(rtl) {
+    border-right: 1px solid $borders_color;
+    border-left-style: none;
+  }
+
+  @at-root %sidebar_right
+  &:dir(rtl),
+  &.right {
+    border-left: 1px solid $borders_color;
+    border-right-style: none;
+  }
+
   &:backdrop {
     background-color: $backdrop_sidebar_bg_color;
+    border-color: $backdrop_borders_color;
   }
 
   :selected { // FIXME: what this is supposed to select
@@ -3266,9 +3281,20 @@ filechooser {
   }
 
   list { background-color: transparent; }
+
+  paned & { &.left, &.right, &.left:dir(rtl), &:dir(rtl), &:dir(ltr), & { border-style: none; }}
 }
 
 stacksidebar {
+  &.sidebar {
+    &:dir(ltr) list,
+    &.left list,
+    &.left:dir(rtl) list { @extend %sidebar_left; }
+
+    &:dir(rtl) list,
+    &.right list { @extend %sidebar_right; }
+  }
+
   row {
     padding: 10px 4px;
 

gtk/theme/Adwaita/gtk-contained-dark.css

@@ -105,10 +105,6 @@ headerbar .subtitle {
 assistant .sidebar {
   background-color: #292929;
   border-top: 1px solid #1c1f1f; }
-  assistant .sidebar:dir(ltr) {
-    border-right: 1px solid #1c1f1f; }
-  assistant .sidebar:dir(rtl) {
-    border-left: 1px solid #1c1f1f; }
   assistant .sidebar:backdrop {
     background-color: #2c2c2c;
     border-color: #1f2222; }
@@ -3304,17 +3300,17 @@ printdialog .dialog-action-box {
 /**********
  * Frames *
  **********/
-frame border,
+frame > border,
 .frame {
   box-shadow: none;
   margin: 0;
   padding: 0;
   border-radius: 0;
   border: 1px solid #1c1f1f; }
-  frame border.flat,
+  frame > border.flat,
   .frame.flat {
     border-style: none; }
-  frame border:backdrop,
+  frame > border:backdrop,
   .frame:backdrop {
     border-color: #1f2222; }
 
@@ -3601,12 +3597,23 @@ filechooser #pathbarbox {
  * Sidebar *
  ***********/
 .sidebar {
-  border: none;
+  border-style: none;
   background-color: #313434; }
+  stacksidebar.sidebar:dir(ltr) list, stacksidebar.sidebar.left list, stacksidebar.sidebar.left:dir(rtl) list, .sidebar:dir(ltr), .sidebar.left, .sidebar.left:dir(rtl) {
+    border-right: 1px solid #1c1f1f;
+    border-left-style: none; }
+  stacksidebar.sidebar:dir(rtl) list
+  .sidebar:dir(rtl), stacksidebar.sidebar.right list
+  .sidebar:dir(rtl), .sidebar.right {
+    border-left: 1px solid #1c1f1f;
+    border-right-style: none; }
   .sidebar:backdrop {
-    background-color: #333636; }
+    background-color: #333636;
+    border-color: #1f2222; }
   .sidebar list {
     background-color: transparent; }
+  paned .sidebar.left, paned .sidebar.right, paned .sidebar.left:dir(rtl), paned .sidebar:dir(rtl), paned .sidebar:dir(ltr), paned .sidebar {
+    border-style: none; }
 
 stacksidebar row {
   padding: 10px 4px; }

gtk/theme/Adwaita/gtk-contained.css

@@ -105,10 +105,6 @@ headerbar .subtitle {
 assistant .sidebar {
   background-color: #ffffff;
   border-top: 1px solid #9d9d99; }
-  assistant .sidebar:dir(ltr) {
-    border-right: 1px solid #9d9d99; }
-  assistant .sidebar:dir(rtl) {
-    border-left: 1px solid #9d9d99; }
   assistant .sidebar:backdrop {
     background-color: white;
     border-color: #a5a5a1; }
@@ -3335,17 +3331,17 @@ printdialog .dialog-action-box {
 /**********
  * Frames *
  **********/
-frame border,
+frame > border,
 .frame {
   box-shadow: none;
   margin: 0;
   padding: 0;
   border-radius: 0;
   border: 1px solid #9d9d99; }
-  frame border.flat,
+  frame > border.flat,
   .frame.flat {
     border-style: none; }
-  frame border:backdrop,
+  frame > border:backdrop,
   .frame:backdrop {
     border-color: #a5a5a1; }
 
@@ -3634,12 +3630,23 @@ filechooser #pathbarbox {
  * Sidebar *
  ***********/
 .sidebar {
-  border: none;
+  border-style: none;
   background-color: #f4f4f3; }
+  stacksidebar.sidebar:dir(ltr) list, stacksidebar.sidebar.left list, stacksidebar.sidebar.left:dir(rtl) list, .sidebar:dir(ltr), .sidebar.left, .sidebar.left:dir(rtl) {
+    border-right: 1px solid #9d9d99;
+    border-left-style: none; }
+  stacksidebar.sidebar:dir(rtl) list
+  .sidebar:dir(rtl), stacksidebar.sidebar.right list
+  .sidebar:dir(rtl), .sidebar.right {
+    border-left: 1px solid #9d9d99;
+    border-right-style: none; }
   .sidebar:backdrop {
-    background-color: #f4f4f3; }
+    background-color: #f4f4f3;
+    border-color: #a5a5a1; }
   .sidebar list {
     background-color: transparent; }
+  paned .sidebar.left, paned .sidebar.right, paned .sidebar.left:dir(rtl), paned .sidebar:dir(rtl), paned .sidebar:dir(ltr), paned .sidebar {
+    border-style: none; }
 
 stacksidebar row {
   padding: 10px 4px; }