Improve contrast in weather report, similar to GTK2 + Adwaita (bug #15806)

panel-plugin/weather-summary.c

@@ -947,13 +947,17 @@ make_forecast(plugin_data *data)
     GtkCssProvider *provider = gtk_css_provider_new ();
     gchar *css_string;
 
-    css_string = g_strdup (".forecast-cell.lightbg { background-color: rgba(0, 0, 0, 0.2); }"
-                           ".forecast-cell.darkbg { background-color: rgba(0, 0, 0, 0.4); }");
+    GtkStyleContext *ctx;
+
+    css_string = g_strdup (".forecast-cell.lightbg { background-color: rgba(0, 0, 0, 0.05); }"
+                           ".forecast-cell.darkbg { background-color: rgba(0, 0, 0, 0.6); }");
 
     gtk_css_provider_load_from_data (provider, css_string, -1, NULL);
     gtk_style_context_add_provider_for_screen (screen, GTK_STYLE_PROVIDER (provider), GTK_STYLE_PROVIDER_PRIORITY_APPLICATION);
 
     grid = gtk_grid_new ();
+    ctx = gtk_widget_get_style_context (GTK_WIDGET (grid));
+    gtk_style_context_add_class (ctx, "background");
 
     gtk_grid_set_row_spacing(GTK_GRID (grid), 0);
     gtk_grid_set_column_spacing(GTK_GRID (grid), 0);