diff --git a/src/gui/gcal-window.c b/src/gui/gcal-window.c
index d185df0d..602cbc50 100644
--- a/src/gui/gcal-window.c
+++ b/src/gui/gcal-window.c
@@ -276,25 +276,20 @@ update_active_date (GcalWindow *window,
 static void
 recalculate_calendar_colors_css (GcalWindow *self)
 {
+  g_autoptr (GString) css_colors = NULL;
   g_autoptr (GError) error = NULL;
   g_autoptr (GList) calendars = NULL;
-  g_autofree gchar *new_css_data = NULL;
-  g_auto (GStrv) new_css_snippets = NULL;
   GcalManager *manager;
-  GQuark color_id;
-  GList *l;
-  gint arr_length;
-  gint i = 0;
 
+  css_colors = g_string_new (NULL);
   manager = gcal_context_get_manager (self->context);
   calendars = gcal_manager_get_calendars (manager);
-  arr_length = g_list_length (calendars);
-  new_css_snippets = g_new0 (gchar*, arr_length + 2);
-  for (l = calendars; l; l = l->next, i++)
+  for (GList *l = calendars; l; l = l->next)
     {
       g_autofree gchar* color_str = NULL;
       const GdkRGBA *color;
       GcalCalendar *calendar;
+      GQuark color_id;
 
       calendar = GCAL_CALENDAR (l->data);
 
@@ -302,11 +297,10 @@ recalculate_calendar_colors_css (GcalWindow *self)
       color_str = gdk_rgba_to_string (color);
       color_id = g_quark_from_string (color_str);
 
-      new_css_snippets[i] = g_strdup_printf (".color-%u { --event-bg-color: %s; }", color_id, color_str);
+      g_string_append_printf (css_colors, ".color-%u { --event-bg-color: %s; }\n", color_id, color_str);
     }
 
-  new_css_data = g_strjoinv ("\n", new_css_snippets);
-  gtk_css_provider_load_from_string (self->colors_provider, new_css_data);
+  gtk_css_provider_load_from_string (self->colors_provider, css_colors->str);
 
   if (error)
     g_warning ("Error creating custom stylesheet. %s", error->message);