Application: hard code elementary styles (#497)

Author: danirabbit

data/wingpanel.appdata.xml.in

@@ -10,11 +10,13 @@
   <description>
     <p>The extensible top panel for Pantheon. Wingpanel is an empty container that accepts indicators as extensions, including the applications menu.</p>
   </description>
+
   <releases>
     <release version="3.0.4" date="2023-18-25" urgency="medium">
       <description>
         <p>Improvements:</p>
         <ul>
+          <li>Always use elementary visual resources</li>
           <li>Esc to close popovers</li>
           <li>Updated translations</li>
         </ul>
@@ -23,6 +25,7 @@
         <issue url="https://github.com/elementary/wingpanel/issues/106">Indicators re-animate when an icon is removed</issue>
       </issues>
     </release>
+
     <release version="3.0.3" date="2022-10-17" urgency="medium">
       <description>
         <p>Improvements:</p>

src/Application.vala

@@ -85,11 +85,16 @@ public class Wingpanel.Application : Gtk.Application {
 
             var granite_settings = Granite.Settings.get_default ();
             var gtk_settings = Gtk.Settings.get_default ();
+            gtk_settings.gtk_icon_theme_name = "elementary";
 
-            gtk_settings.gtk_application_prefer_dark_theme = granite_settings.prefers_color_scheme == Granite.Settings.ColorScheme.DARK;
+            if (!gtk_settings.gtk_theme_name.has_prefix ("io.elementary")) {
+                gtk_settings.gtk_theme_name = "io.elementary.stylesheet.blueberry";
+            }
+
+            gtk_settings.gtk_application_prefer_dark_theme = granite_settings.prefers_color_scheme == DARK;
 
             granite_settings.notify["prefers-color-scheme"].connect (() => {
-                gtk_settings.gtk_application_prefer_dark_theme = granite_settings.prefers_color_scheme == Granite.Settings.ColorScheme.DARK;
+                gtk_settings.gtk_application_prefer_dark_theme = granite_settings.prefers_color_scheme == DARK;
             });
         }