diff --git a/wasm/app/index.html b/wasm/app/index.html
index 440bd4f75..bb7f2a98f 100644
--- a/wasm/app/index.html
+++ b/wasm/app/index.html
@@ -19,7 +19,7 @@
       }
 
       #run-btn {
-        width: 4em;
+        width: 6em;
         height: 2em;
         font-size: 24px;
       }