[gnome-games/wip/exalm/libhandy2: 1/6] fixme: Add css from libhandy example

[Alexander Mikhaylenko <alexm src gnome org>]

commit c041d267fd0736acfc70aefe5190d55be88b5029
Author: Alexander Mikhaylenko <exalm7659 gmail com>
Date:   Wed Sep 12 14:29:52 2018 +0500

    fixme: Add css from libhandy example
    
    This will be removed later.

 data/gtk-style.css | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)
---
diff --git a/data/gtk-style.css b/data/gtk-style.css
index 83ae1888..59413d5a 100644
--- a/data/gtk-style.css
+++ b/data/gtk-style.css
@@ -30,3 +30,36 @@ gamesgamethumbnail {
                    @theme_unfocused_bg_color;
        border-color: @unfocused_borders;
 }
+
+stacksidebar list {
+  border-left-width: 0px;
+  border-right-width: 0px;
+}
+
+/* Needed for seaprators to look good. These have been submitted upstream here:
+ * https://gitlab.gnome.org/GNOME/gtk/merge_requests/323
+ */
+
+separator.sidebar {
+  background-color: @borders;
+  border-style: none;
+  margin: 0px 0px 0px 0px;
+}
+
+separator.sidebar:backdrop {
+  background-color: @unfocused_borders;
+}
+
+separator.sidebar.selection-mode,
+.selection-mode separator.sidebar {
+  background-color: mix(@theme_selected_bg_color, #000, 0.2);
+}
+
+/* Needed for HdyTitleBar to work. This has been merged upstream but no release
+ * include it yet, it is likely to be released as part of GTK+ 3.24.1.
+ */
+headerbar.titlebar headerbar:not(.titlebar) {
+  background-color: rgba (0, 0, 0, 0);
+  background-image: none;
+  box-shadow: none;
+}