diff --git a/web/index.html b/web/index.html
index 6a97472..b1d979f 100644
--- a/web/index.html
+++ b/web/index.html
@@ -1,19 +1,30 @@
-<!DOCTYPE html>
-<html lang="en">
-
-<head>
-    <meta charset="utf-8">
-    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
-    <link rel="modulepreload" href="/pkg/package.js" as="script" type="text/javascript">
-    <link rel="preload" href="/pkg/package_bg.wasm" as="fetch" type="application/wasm" crossorigin="anonymous">
-</head>
-
-<body>
-    <section id="app"></section>
-    <script type="module">
-        import init from '/pkg/package.js';
-        init('/pkg/package_bg.wasm');
-    </script>
-</body>
-
-</html>
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+    <link rel="modulepreload" href="/pkg/package.js" as="script" type="text/javascript">
+    <link rel="preload" href="/pkg/package_bg.wasm" as="fetch" type="application/wasm" crossorigin="anonymous">
+<style>
+.message {
+  padding-left: 0.5em;
+}
+.body {
+  padding-bottom: 1em;
+}
+.error {
+  background-color: red;
+}
+</style>
+</head>
+
+<body>
+    <section id="app"></section>
+    <script type="module">
+        import init from '/pkg/package.js';
+        init('/pkg/package_bg.wasm');
+    </script>
+</body>
+
+</html>
