diff --git a/website/siteConfig.js b/website/siteConfig.js
index d8a4f0e..d976157 100644
--- a/website/siteConfig.js
+++ b/website/siteConfig.js
@@ -48,7 +48,7 @@ const siteConfig = {
 
   onPageNav: "separate",
 
-  scripts: ["/js/pattern-validity.js"],
+  scripts: ["/js/pattern-validity.js", "/js/change-css-in-demo-page.js"],
 
   algolia: {
     apiKey: "29d680ce97507c5cd2836c6c74783c05",
diff --git a/website/static/js/change-css-in-demo-page.js b/website/static/js/change-css-in-demo-page.js
new file mode 100644
index 0000000..62e7b63
--- /dev/null
+++ b/website/static/js/change-css-in-demo-page.js
@@ -0,0 +1,5 @@
+if (window.location.pathname === "/demo") {
+  document.addEventListener("DOMContentLoaded", function() {
+    document.querySelector(".headerWrapper.wrapper").style.maxWidth = "100%";
+  });
+}