diff --git a/index.html b/index.html
index bc3b415..027bd72 100644
--- a/index.html
+++ b/index.html
@@ -1 +1,36 @@
-if you are seeing this, the hosting app is working.
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+<!DOCTYPE html>
+<html lang="en">
+<head>
+  <meta charset="UTF-8" />
+  <title>Dark Mode Test</title>
+  <link rel="stylesheet" href="style.css" />
+</head>
+<body>
+  <div class="container">
+    <h1>Dark Mode Test</h1>
+    <p>This is a simple dual-file dark mode website.</p>
+
+    <button id="toggle">Toggle Dark Mode</button>
+  </div>
+
+  <script>
+    const toggle = document.getElementById("toggle");
+
+    // Load saved theme
+    if (localStorage.getItem("theme") === "dark") {
+      document.body.classList.add("dark");
+    }
+
+    toggle.addEventListener("click", () => {
+      document.body.classList.toggle("dark");
+
+      // Save theme
+      if (document.body.classList.contains("dark")) {
+        localStorage.setItem("theme", "dark");
+      } else {
+        localStorage.setItem("theme", "light");
+      }
+    });
+  </script>
+</body>
+</html>
