diff --git a/assets/js/acas-backend-instance.js b/assets/js/acas-backend-instance.js
index 790ee3e..8739a10 100644
--- a/assets/js/acas-backend-instance.js
+++ b/assets/js/acas-backend-instance.js
@@ -196,7 +196,7 @@ class BackendInstance {
                 return [
                     ...baseStyleArr,
                     `fill: ${fill ? fill : 'crimson'};`,
-                    'opacity: 0.3;'
+                    'opacity: 0.5;'
                 ].join('\n');
         }
     };