diff --git a/network.d2 b/network.d2
index c9c3c6c..95a00c8 100644
--- a/network.d2
+++ b/network.d2
@@ -1,4 +1,11 @@
 classes: {
+  zone: {
+    style: {
+      fill: transparent
+      border-radius: 12
+      stroke-dash: 5
+    }
+  }
   emptybox: {
     style.opacity: 0
     *: {