[gnome-themes-standard] gtk3: improve style of GtkScale's trough

[Cosimo Cecchi <cosimoc src gnome org>]

commit 1f26f979629e3e237cda5c4b12d10dce4f94a954
Author: Cosimo Cecchi <cosimoc gnome org>
Date:   Tue Apr 9 15:47:43 2013 -0400

    gtk3: improve style of GtkScale's trough
    
    https://bugzilla.gnome.org/show_bug.cgi?id=695563

 themes/Adwaita/gtk-3.0/gtk-main-dark.css           |    3 +++
 themes/Adwaita/gtk-3.0/gtk-main.css                |    3 +++
 themes/Adwaita/gtk-3.0/gtk-widgets-backgrounds.css |   14 ++++++++++++++
 themes/Adwaita/gtk-3.0/gtk-widgets.css             |    4 ++--
 4 files changed, 22 insertions(+), 2 deletions(-)
---
diff --git a/themes/Adwaita/gtk-3.0/gtk-main-dark.css b/themes/Adwaita/gtk-3.0/gtk-main-dark.css
index 1b82ac2..04823a8 100644
--- a/themes/Adwaita/gtk-3.0/gtk-main-dark.css
+++ b/themes/Adwaita/gtk-3.0/gtk-main-dark.css
@@ -91,6 +91,9 @@
 @define-color internal_element_prelight #eeeeee;
 @define-color internal_element_insensitive mix(@internal_element_color, @theme_base_color, 0.65);
 
+ define-color scale_trough_bg_a @borders;
+ define-color scale_trough_bg_b shade(@theme_bg_color, 0.95);
+ define-color scale_shadow @theme_bg_color;
 @define-color scale_progress_fill #2c85e2;
 @define-color scale_highlight_border #182f4c;
 @define-color scale_highlight_bg #356599;
diff --git a/themes/Adwaita/gtk-3.0/gtk-main.css b/themes/Adwaita/gtk-3.0/gtk-main.css
index 01128ac..cecd08c 100644
--- a/themes/Adwaita/gtk-3.0/gtk-main.css
+++ b/themes/Adwaita/gtk-3.0/gtk-main.css
@@ -91,6 +91,9 @@
 @define-color internal_element_prelight @theme_text_color;
 @define-color internal_element_insensitive mix(@internal_element_color, @theme_base_color, 0.7);
 
+ define-color scale_trough_bg_a #c0c0bd;
+ define-color scale_trough_bg_b #f2f2f0;
+ define-color scale_shadow alpha(white, 0.50);
 @define-color scale_progress_fill #2c85e2;
 @define-color scale_highlight_border #426ea8;
 @define-color scale_highlight_bg #729fce;
diff --git a/themes/Adwaita/gtk-3.0/gtk-widgets-backgrounds.css 
b/themes/Adwaita/gtk-3.0/gtk-widgets-backgrounds.css
index dc8209c..8180579 100644
--- a/themes/Adwaita/gtk-3.0/gtk-widgets-backgrounds.css
+++ b/themes/Adwaita/gtk-3.0/gtk-widgets-backgrounds.css
@@ -230,6 +230,20 @@ GtkComboBox.combobox-entry .button:insensitive:backdrop,
     background-color: @unfocused_dark_bg;
 }
 
+.scale.trough {
+    background-image: linear-gradient(to bottom,
+                                      @scale_trough_bg_a,
+                                      @scale_trough_bg_b
+                                      );
+}
+
+.scale.trough.vertical {
+    background-image: linear-gradient(to right,
+                                      @scale_trough_bg_a,
+                                      @scale_trough_bg_b
+                                      );
+}
+
 /* Active switch background*/
 GtkSwitch.trough:active,
 .scale.progressbar {
diff --git a/themes/Adwaita/gtk-3.0/gtk-widgets.css b/themes/Adwaita/gtk-3.0/gtk-widgets.css
index 5f40e10..8d72276 100644
--- a/themes/Adwaita/gtk-3.0/gtk-widgets.css
+++ b/themes/Adwaita/gtk-3.0/gtk-widgets.css
@@ -1089,11 +1089,11 @@ GtkLevelBar.vertical {
 }
 
 .scale.trough {
-    box-shadow: inset 0 -1px @theme_bg_color;
+    box-shadow: inset 0 -1px @scale_shadow;
 }
 
 .scale.trough.vertical {
-    box-shadow: inset -1px 0 @theme_bg_color;
+    box-shadow: inset -1px 0 @scale_shadow;
 }
 
 .scale.trough.highlight {