diff --git a/static/c4.css b/static/c4.css
index baa870b..b9a0d3a 100644
--- a/static/c4.css
+++ b/static/c4.css
@@ -110,7 +110,7 @@ h1, h1 a  {
 #mapgrid {
     outline: 2px solid #333;
     background-color: #dfaa37;
-    border-radius: 4px;
+    border-radius: min(4px, 25%);
     animation: blinker 1s infinite;
 }