diff --git a/frontend/index.html b/frontend/index.html
index 1824f2c..4204d27 100644
--- a/frontend/index.html
+++ b/frontend/index.html
@@ -1,26 +1,35 @@
-<!DOCTYPE html>
+<!doctype html>
 <html>
-<head>
-    <meta charset="utf-8">
-    <title>Elm UI Website</title>
-    <style>
-        @font-face {
-            font-family: 'Courier Prime';
-            src: url('assets/CourierPrime-Regular.ttf') format('truetype');
-            font-weight: normal;
-            font-style: normal;
-        }
-    </style>
-</head>
-<body>
-    <div id="elm"></div>
-    <script src="elm.min.js"></script>
-    <script src="ports.websocket.js"></script>
-    <script>
-        var app = Elm.Main.init({
-            node: document.getElementById('elm')
-        });
-        initSockets(app);
-    </script>
-</body>
+    <head>
+        <meta charset="utf-8" />
+        <title>Elm UI Website</title>
+        <style>
+            @font-face {
+                font-family: "Courier Prime";
+                src: url("assets/CourierPrime-Regular.ttf") format("truetype");
+                font-weight: normal;
+                font-style: normal;
+            }
+        </style>
+    </head>
+    <body>
+        <div id="elm"></div>
+        <script src="elm.min.js"></script>
+        <script src="ports.websocket.js"></script>
+        <script>
+            var app = Elm.Main.init({
+                node: document.getElementById("elm"),
+            });
+            initSockets(app);
+            const allowedKeys = ["l"];
+            document.addEventListener("keydown", (event) => {
+                if (
+                    event.ctrlKey &&
+                    allowedKeys.includes(event.key.toLowerCase())
+                ) {
+                    event.preventDefault();
+                }
+            });
+        </script>
+    </body>
 </html>
