diff --git a/py/hexagram/cluster.py b/py/hexagram/cluster.py
index 98a1d4d..1af04e7 100644
--- a/py/hexagram/cluster.py
+++ b/py/hexagram/cluster.py
@@ -76,7 +76,7 @@ class Cluster():
                                           rpm_max))
 
     def draw_bg(self, cr: cairo.Context):
-        cr.set_source_rgb(0, 0, 0)
+        cr.set_source_rgb(0.1, 0.1, 0.1)
         cr.rectangle(0, 0, self.WIDTH, self.HEIGHT)
         cr.fill()