diff --git a/tools/diagram/src/next-key-locks.svg b/tools/diagram/src/next-key-locks.svg
index 857ec22f..67b8b28e 100644
--- a/tools/diagram/src/next-key-locks.svg
+++ b/tools/diagram/src/next-key-locks.svg
@@ -15,7 +15,7 @@
     .dash { stroke-dasharray: 5 4; }
     .line { stroke: #666; stroke-width: 1.3; fill: none; }
     .frame { fill: none; stroke: #999; stroke-width: 1; stroke-dasharray: 4 3; }
-    .shadow { fill: #C0C0C0; }
+    .shadow { fill: #DADADA; }
   </style>
   <defs>
     <marker id="a" viewBox="0 0 10 10" refX="9" refY="5" markerWidth="7" markerHeight="7" orient="auto-start-reverse">