[pitivi] Preferences: Add borders for shortcuts list

[Alexandru Băluț <alexbalut src gnome org>]

commit 99e154ef0f594f03df94d0f2bc8da91e4ae5988f
Author: Diego Garcia Gangl <dnicolas gmail com>
Date:   Sat Apr 27 21:08:28 2019 -0300

    Preferences: Add borders for shortcuts list

 pitivi/dialogs/prefs.py |  9 +++++++--
 pitivi/utils/ui.py      | 18 ++++++++++++++++++
 2 files changed, 25 insertions(+), 2 deletions(-)
---
diff --git a/pitivi/dialogs/prefs.py b/pitivi/dialogs/prefs.py
index 91f1bb3b..576ac7bb 100644
--- a/pitivi/dialogs/prefs.py
+++ b/pitivi/dialogs/prefs.py
@@ -307,11 +307,14 @@ class PreferencesDialog(Loggable):
                 self.list_store.append(item)
                 self.action_ids[action] = index
                 index += 1
+
         self.content_box.bind_model(self.list_store, self._create_widget_func, None)
         self.content_box.set_header_func(self._add_header_func, None)
         self.content_box.connect("row_activated", self.__row_activated_cb)
         self.content_box.set_selection_mode(Gtk.SelectionMode.NONE)
         self.content_box.props.margin = PADDING * 3
+        self.content_box.get_style_context().add_class('prefs_list')
+
         viewport = Gtk.Viewport()
         viewport.add(self.content_box)
 
@@ -386,6 +389,9 @@ class PreferencesDialog(Loggable):
             prev_group = None
 
         if prev_group != group:
+            if before is not None:
+                before.get_style_context().add_class("last")
+
             header = Gtk.Label()
             header.set_use_markup(True)
             group_title = self.app.shortcuts.group_titles[group]
@@ -402,8 +408,7 @@ class PreferencesDialog(Loggable):
             box.get_style_context().add_class("background")
             box.show_all()
             row.set_header(box)
-        else:
-            row.set_header(Gtk.Separator(orientation=Gtk.Orientation.HORIZONTAL))
+            row.get_style_context().add_class("first")
 
     def __reset_accelerator_cb(self, unused_button, item):
         """Resets the accelerator to the default value."""
diff --git a/pitivi/utils/ui.py b/pitivi/utils/ui.py
index 99e97660..fe447b4f 100644
--- a/pitivi/utils/ui.py
+++ b/pitivi/utils/ui.py
@@ -236,6 +236,24 @@ PREFERENCES_CSS = """
     .sidebar row {
         padding: 10px 40px 10px 4px;
     }
+
+    .prefs_list row {
+        border-left: 1px solid rgb(32, 32, 32);
+        border-right: 1px solid rgb(32, 32, 32);
+        border-bottom: 1px solid rgba(25, 25, 25, 0.2);
+    }
+
+    .prefs_list .first {
+        border-top: 1px solid rgb(32, 32, 32);
+    }
+
+    /* This covers the case for the last item in a group,
+       and the last item in the list */
+    .prefs_list,
+    .prefs_list .last {
+        border-bottom: 1px solid rgb(32, 32, 32);
+    }
+
 """