[gnome-themes-standard/gnome-3-8] gtk3: improve style of GtkScale's trough

[Cosimo Cecchi <cosimoc src gnome org>]

commit e8213d036c485f3a4b568b3a034ada100e5e0b26
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 33c1301..639605b 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 1b0e54a..74893fe 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 6c39933..c648f6b 100644
--- a/themes/Adwaita/gtk-3.0/gtk-widgets.css
+++ b/themes/Adwaita/gtk-3.0/gtk-widgets.css
@@ -1082,11 +1082,11 @@ 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 {