diff --git a/gtk/theme/HighContrast/_common.scss b/gtk/theme/HighContrast/_common.scss
index 1d8721f7d8..f2e3e59d24 100644
--- a/gtk/theme/HighContrast/_common.scss
+++ b/gtk/theme/HighContrast/_common.scss
@@ -766,7 +766,7 @@ GtkComboBox {
     color: $insensitive_fg_color;
   }
   .menuitem { text-shadow: none; }
-  .separator.vertical {
+  & separator.vertical {
     // always disable separators
     -GtkWidget-wide-separators: true;
   }
@@ -896,7 +896,7 @@ GtkComboBox {
     padding: 0 12px;
   }
   .header-bar-separator,
-  & > GtkBox > .separator.vertical {
+  & > GtkBox > separator.vertical {
     -GtkWidget-wide-separators: true;
     -GtkWidget-separator-width: 1px;
     border-width: 0 1px;
@@ -1193,7 +1193,7 @@ GtkTreeView.view.progressbar { //Progressbar in treeview cells
   & > .toolbar {
     background-color: transparent;
   }
-  .separator {
+  separator {
     color: $fg_color;
     background-color: transparent;
     border: 0;
@@ -1922,7 +1922,7 @@ GtkScrolledWindow {
 }
 
 //vbox and hbox separators
-.separator {
+separator {
   // always disable separators
   // -GtkWidget-wide-separators: true;
   color: $borders_color;
@@ -2244,8 +2244,8 @@ GtkPlacesSidebar.sidebar {
     color: $fg_color;
     background-color: transparent;
 
-    .separator,
-    .separator:backdrop { @extend .separator; }
+    separator,
+    separator:backdrop { @extend separator; }
 
     .image { // icons color
       color: mix($fg_color, $bg_color, 70%);
diff --git a/gtk/theme/HighContrast/gtk.css b/gtk/theme/HighContrast/gtk.css
index 12b353b0b0..74fd38fef0 100644
--- a/gtk/theme/HighContrast/gtk.css
+++ b/gtk/theme/HighContrast/gtk.css
@@ -958,7 +958,7 @@ GtkComboBox {
     color: gray; }
   GtkComboBox .menuitem {
     text-shadow: none; }
-  GtkComboBox .separator.vertical, GtkComboBox GtkPlacesSidebar.sidebar .view .vertical.separator, GtkPlacesSidebar.sidebar .view GtkComboBox .vertical.separator {
+  GtkComboBox separator.vertical, GtkComboBox GtkPlacesSidebar.sidebar .view separator.vertical, GtkPlacesSidebar.sidebar .view GtkComboBox separator.vertical {
     -GtkWidget-wide-separators: true; }
   GtkComboBox.combobox-entry entry {
     border-radius: 3px 0 0 3px; }
@@ -1034,11 +1034,11 @@ GtkComboBox {
   .header-bar .subtitle {
     font-size: 80%;
     padding: 0 12px; }
-  .titlebar .header-bar-separator, .titlebar > GtkBox > .separator.vertical,
-  GtkPlacesSidebar.sidebar .view .titlebar > GtkBox > .vertical.separator:backdrop,
+  .titlebar .header-bar-separator, .titlebar > GtkBox > separator.vertical,
+  GtkPlacesSidebar.sidebar .view .titlebar > GtkBox > separator.vertical:backdrop,
   .header-bar .header-bar-separator,
-  .header-bar > GtkBox > .separator.vertical,
-  GtkPlacesSidebar.sidebar .view .header-bar > GtkBox > .vertical.separator:backdrop {
+  .header-bar > GtkBox > separator.vertical,
+  GtkPlacesSidebar.sidebar .view .header-bar > GtkBox > separator.vertical:backdrop {
     -GtkWidget-wide-separators: true;
     -GtkWidget-separator-width: 1px;
     border-width: 0 1px;
@@ -1359,7 +1359,7 @@ GtkTreeView.view.progressbar {
     box-shadow: none; }
   .popover > .list, .popover > .view, .popover > .toolbar {
     background-color: transparent; }
-  .popover .separator, .popover GtkPlacesSidebar.sidebar .view .separator, GtkPlacesSidebar.sidebar .view .popover .separator {
+  .popover separator, .popover GtkPlacesSidebar.sidebar .view separator, GtkPlacesSidebar.sidebar .view .popover separator {
     color: #000;
     background-color: transparent;
     border: 0; }
@@ -2096,10 +2096,10 @@ GtkScrolledWindow .frame {
 GtkScrolledWindow GtkViewport.frame {
   border-style: none; }
 
-.separator, GtkPlacesSidebar.sidebar .view .separator,
-GtkPlacesSidebar.sidebar .view .separator:backdrop {
+separator, GtkPlacesSidebar.sidebar .view separator,
+GtkPlacesSidebar.sidebar .view separator:backdrop {
   color: gray; }
-  GtkFileChooserButton .separator.vertical, GtkFileChooserButton GtkPlacesSidebar.sidebar .view .vertical.separator, GtkPlacesSidebar.sidebar .view GtkFileChooserButton .vertical.separator, GtkFontButton .separator.vertical, GtkFontButton GtkPlacesSidebar.sidebar .view .vertical.separator, GtkPlacesSidebar.sidebar .view GtkFontButton .vertical.separator {
+  GtkFileChooserButton separator.vertical, GtkFileChooserButton GtkPlacesSidebar.sidebar .view separator.vertical, GtkPlacesSidebar.sidebar .view GtkFileChooserButton separator.vertical, GtkFontButton separator.vertical, GtkFontButton GtkPlacesSidebar.sidebar .view separator.vertical, GtkPlacesSidebar.sidebar .view GtkFontButton separator.vertical {
     -GtkWidget-wide-separators: true; }
 
 /*********