[gitg/gnome-3-20] Fix style of language label in dark theme

[Ignacio Casal Quinteiro <icq src gnome org>]

commit eda83862a8a8b604747cf5967ce5963e10367b9e
Author: Jesse van den Kieboom <jessevdk gnome org>
Date:   Sun Jun 5 11:47:10 2016 +0200

    Fix style of language label in dark theme
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766532

 gitg/gitg-window.vala                  |   19 +++++++++++++++++++
 libgitg/resources/ui/libgitg-style.css |    8 ++++++--
 2 files changed, 25 insertions(+), 2 deletions(-)
---
diff --git a/gitg/gitg-window.vala b/gitg/gitg-window.vala
index e7d085e..b4b6150 100644
--- a/gitg/gitg-window.vala
+++ b/gitg/gitg-window.vala
@@ -363,6 +363,25 @@ public class Window : Gtk.ApplicationWindow, GitgExt.Application, Initable
                                          SettingsBindFlags.GET | SettingsBindFlags.SET);
        }
 
+       protected override void style_updated()
+       {
+               base.style_updated();
+
+               var settings = Gtk.Settings.get_default();
+               var theme = Environment.get_variable("GTK_THEME");
+
+               var dark = settings.gtk_application_prefer_dark_theme || (theme != null && 
theme.has_suffix(":dark"));
+
+               if (dark)
+               {
+                       get_style_context().add_class("dark");
+               }
+               else
+               {
+                       get_style_context().remove_class("dark");
+               }
+       }
+
        protected override bool delete_event(Gdk.EventAny event)
        {
                var ret = false;
diff --git a/libgitg/resources/ui/libgitg-style.css b/libgitg/resources/ui/libgitg-style.css
index d5abf1f..877a758 100644
--- a/libgitg/resources/ui/libgitg-style.css
+++ b/libgitg/resources/ui/libgitg-style.css
@@ -77,8 +77,8 @@ gitg-diffstat.no-frame.removed-only {
        border-radius: 0px 3px 3px 0px;
 }
 
-gitg-diffstat.removed.dark,
-gitg-diffstat.removed-only.dark {
+.dark gitg-diffstat.removed,
+.dark gitg-diffstat.removed-only {
        background-color: rgb(164, 0, 0);
 }
 
@@ -108,3 +108,7 @@ GitgDiffViewOptions {
        border-radius: 3px;
        padding: 3px;
 }
+
+.dark .language-frame {
+       background-color: #535353;
+}