[gnome-builder] style: tweak panel header styling

[Christian Hergert <chergert src gnome org>]

commit 1cdc81cdddf594e2ca47bbdebe6b279eefccc466
Author: Christian Hergert <christian hergert me>
Date:   Fri Jan 15 10:21:42 2016 -0800

    style: tweak panel header styling

 data/theme/Adwaita-dark.css |   10 +++++++---
 data/theme/Adwaita.css      |    8 ++++++--
 2 files changed, 13 insertions(+), 5 deletions(-)
---
diff --git a/data/theme/Adwaita-dark.css b/data/theme/Adwaita-dark.css
index b202d92..a7b2ef6 100644
--- a/data/theme/Adwaita-dark.css
+++ b/data/theme/Adwaita-dark.css
@@ -52,9 +52,13 @@ layouttab:backdrop {
 
 
 layoutpane > box.vertical:first-child > box.horizontal {
-  background: #d6d6d6;
-  box-shadow: inset 0 2px 3px -1px #b6b6b6;
+  background-color: #303535;
+  box-shadow: 0 4px 3px -5px #2c3030 inset,
+              0 -1px 0 #1c1f1f inset;
+}
+layoutpane:backdrop > box.vertical:first-child > box.horizontal {
+  box-shadow: 0 -1px 0 #2c3030 inset;
 }
 layoutpane stackswitcher button:checked {
-  box-shadow: 0 -2px 0 #4a90d9 inset;
+  box-shadow: 0 -2px 0 #215d9c inset;
 }
diff --git a/data/theme/Adwaita.css b/data/theme/Adwaita.css
index 3444de0..8563a30 100644
--- a/data/theme/Adwaita.css
+++ b/data/theme/Adwaita.css
@@ -50,8 +50,12 @@ layouttab:backdrop {
 
 
 layoutpane > box.vertical:first-child > box.horizontal {
-  background: #d6d6d6;
-  box-shadow: inset 0 2px 3px -1px #b6b6b6;
+  background-color: #d6d6d6;
+  box-shadow: 0 4px 3px -5px #aaa inset,
+              0 -1px 0 #a1a1a1 inset;
+}
+layoutpane:backdrop > box.vertical:first-child > box.horizontal {
+  box-shadow: 0 -1px 0 #a1a1a1 inset;
 }
 layoutpane stackswitcher button:checked {
   box-shadow: 0 -2px 0 #4a90d9 inset;