diff --git a/pygal/graph/graph.py b/pygal/graph/graph.py
index 81e897e..845c89f 100644
--- a/pygal/graph/graph.py
+++ b/pygal/graph/graph.py
@@ -390,8 +390,7 @@ class Graph(PublicApi):
                     ) / 2,
                     width=self.legend_box_size,
                     height=self.legend_box_size,
-                    class_="color-%d reactive" % (
-                        serie_number % len(self.style.colors))
+                    class_="color-%d reactive" % serie_number
                 )
 
                 if isinstance(title, dict):