diff --git a/app/Controllers/ValidationTestController.php b/app/Controllers/ValidationTestController.php
index f9ad7de..725b64b 100644
--- a/app/Controllers/ValidationTestController.php
+++ b/app/Controllers/ValidationTestController.php
@@ -8,6 +8,14 @@ class ValidationTestController
 {
     public function index()
     {
+        if (is_htmx_request()) {
+            // Only return the form fragment for HTMX requests
+            return view('partials/validation-test', [
+                'errors' => [],
+                'old' => [],
+            ]);
+        }
+
         return view('validation-test', ['title' => 'ValidationTestController Index']);
     }
 
@@ -33,4 +41,4 @@ public function handleForm()
             'email' => $data['email'],
         ]);
     }
-}
\ No newline at end of file
+}
diff --git a/app/Views/Components/navbar.twig b/app/Views/Components/navbar.twig
index 3ead3aa..2ba86e0 100644
--- a/app/Views/Components/navbar.twig
+++ b/app/Views/Components/navbar.twig
@@ -14,7 +14,37 @@
 			<li><a href="#">Docs</a></li>
 			<li><a href="https://github.com/sponsors/yanikkumar"><img src="https://img.shields.io/badge/Sponsor%20Creator-%E2%9D%A4%EF%B8%8F-pink?logo=github-sponsors"/></a></li>
 			<li><a href="#"><img src="https://img.shields.io/github/stars/sproutphp/framework?style=social&link=https%3A%2F%2Fgithub.com%2FSproutPHP%2Fframework"/></a></li>
+			<li>
+				<button id="theme-toggle-btn" aria-label="Toggle dark/light mode" style="background:none;border:none;cursor:pointer;font-size:1.5rem;">
+					<span id="theme-icon">☀️</span>
+				</button>
+			</li>
 		</ul>
 	</nav>
 	<hr/>
 </div>
+
+<script>
+(function() {
+  const themeBtn = document.getElementById('theme-toggle-btn');
+  const themeIcon = document.getElementById('theme-icon');
+  const html = document.documentElement;
+  if (!themeBtn || !themeIcon) return;
+  function setInitialTheme() {
+    let theme = localStorage.getItem('theme');
+    if (!theme) {
+      theme = window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
+    }
+    html.setAttribute('data-theme', theme);
+    themeIcon.textContent = theme === 'dark' ? '🌙' : '☀️';
+  }
+  setInitialTheme();
+  themeBtn.addEventListener('click', function() {
+    const currentTheme = html.getAttribute('data-theme');
+    const newTheme = currentTheme === 'dark' ? 'light' : 'dark';
+    html.setAttribute('data-theme', newTheme);
+    localStorage.setItem('theme', newTheme);
+    themeIcon.textContent = newTheme === 'dark' ? '🌙' : '☀️';
+  });
+})();
+</script>
diff --git a/app/Views/Components/spinner.twig b/app/Views/Components/spinner.twig
new file mode 100644
index 0000000..1194a35
--- /dev/null
+++ b/app/Views/Components/spinner.twig
@@ -0,0 +1,29 @@
+{# SproutPHP Component: spinner.twig #}
+<div id="spinner" class="htmx-indicator">
+  <div class="spinner"></div>
+</div>
+<style>
+#spinner {
+  position: fixed;
+  top: 50%; left: 50%;
+  transform: translate(-50%, -50%);
+  background: rgba(0,0,0,0.7);
+  color: #fff;
+  padding: 1rem 2rem;
+  border-radius: 8px;
+  z-index: 9999;
+}
+.spinner {
+  border: 8px solid #f3f3f3;
+  border-top: 8px solid #3498db;
+  border-radius: 50%;
+  width: 40px;
+  height: 40px;
+  animation: spin 1s linear infinite;
+  margin: 0 auto;
+}
+@keyframes spin {
+  0% { transform: rotate(0deg);}
+  100% { transform: rotate(360deg);}
+}
+</style>
\ No newline at end of file
diff --git a/app/Views/partials/validation-form.twig b/app/Views/partials/validation-form.twig
index 933ac13..82b155a 100644
--- a/app/Views/partials/validation-form.twig
+++ b/app/Views/partials/validation-form.twig
@@ -1,7 +1,9 @@
+{% include "components/spinner.twig" %}
 <form 
     hx-post="/validation-test" 
     hx-target="#form-container" 
     hx-swap="innerHTML"
+    hx-indicator="#spinner"
     method="POST"
     autocomplete="off"
 >
@@ -11,15 +13,28 @@
         <label for="name">Name:</label>
         <input type="text" name="name" id="name" value="{{ old.name|e }}">
         {% if errors.name %}
-            <div class="error" style="color: red;">{{ errors.name }}</div>
+            <div class="error" for="name" style="color: red;">{{ errors.name }}</div>
         {% endif %}
     </div>
     <div>
         <label for="email">Email:</label>
         <input type="email" name="email" id="email" value="{{ old.email|e }}">
         {% if errors.email %}
-            <div class="error" style="color: red;">{{ errors.email }}</div>
+            <div class="error" for="email" style="color: red;">{{ errors.email }}</div>
         {% endif %}
     </div>
-    <button type="submit">Submit</button>
-</form>
\ No newline at end of file
+    <button type="submit">Submit
+    </button>
+</form>
+<script>
+document.addEventListener('focusin', function(e) {
+  if (e.target.matches('input[name="name"]')) {
+    const error = e.target.closest('form').querySelector('.error[for="name"]');
+    if (error) error.remove();
+  }
+  if (e.target.matches('input[name="email"]')) {
+    const error = e.target.closest('form').querySelector('.error[for="email"]');
+    if (error) error.remove();
+  }
+});
+</script>
\ No newline at end of file
diff --git a/app/Views/validation-test.twig b/app/Views/validation-test.twig
index 9322b7e..57c5493 100644
--- a/app/Views/validation-test.twig
+++ b/app/Views/validation-test.twig
@@ -2,10 +2,8 @@
 {% block title %}validation-test{% endblock %}
 
 {% block content %}
-    <h1>validation-test</h1>
-    <p>This is the <strong>validation-test</strong> page.</p>
-        <h1>Validation Test Form</h1>
-        <div id="form-container">
-            {% include "partials/validation-form.twig" %}
-        </div>
+    <h1>Validation Test Form</h1>
+    <div id="form-container">
+        {% include "partials/validation-form.twig" %}
+    </div>
 {% endblock %}
diff --git a/core/Console/PostInstall.php b/core/Console/PostInstall.php
index a545046..c571320 100644
--- a/core/Console/PostInstall.php
+++ b/core/Console/PostInstall.php
@@ -59,11 +59,11 @@ public static function run()
         }
 
         $color = '';
-        $needsColor = in_array($choice, ['5','6','7','8']);
+        $needsColor = in_array($choice, ['5', '6', '7', '8']);
         if ($needsColor) {
             echo "Enter color name (amber, blue, cyan, fuchsia, green, grey, indigo, jade, lime, orange, pink, pumpkin, purple, red, sand, slate, violet, yellow, zinc): ";
             $color = strtolower(trim(fgets(STDIN)));
-            $validColors = ['amber','blue','cyan','fuchsia','green','grey','indigo','jade','lime','orange','pink','pumpkin','purple','red','sand','slate','violet','yellow','zinc'];
+            $validColors = ['amber', 'blue', 'cyan', 'fuchsia', 'green', 'grey', 'indigo', 'jade', 'lime', 'orange', 'pink', 'pumpkin', 'purple', 'red', 'sand', 'slate', 'violet', 'yellow', 'zinc'];
             if (!in_array($color, $validColors)) {
                 echo "Invalid color. Defaulting to blue.\n";
                 $color = 'blue';
@@ -78,21 +78,96 @@ public static function run()
         $file = '';
 
         switch ($choice) {
-            case '1': $file = "pico$min.css"; break;
-            case '2': $file = "pico.classless$min.css"; break;
-            case '3': $file = "pico.conditional$min.css"; break;
-            case '4': $file = "pico.fluid.classless$min.css"; break;
-            case '5': $file = "pico.$color$min.css"; break;
-            case '6': $file = "pico.classless.$color$min.css"; break;
-            case '7': $file = "pico.conditional.$color$min.css"; break;
-            case '8': $file = "pico.fluid.classless.conditional.$color$min.css"; break;
-            case '9': $file = "pico.colors$min.css"; break;
-            default: $file = "pico$min.css"; break;
+            case '1':
+                $file = "pico$min.css";
+                break;
+            case '2':
+                $file = "pico.classless$min.css";
+                break;
+            case '3':
+                $file = "pico.conditional$min.css";
+                break;
+            case '4':
+                $file = "pico.fluid.classless$min.css";
+                break;
+            case '5':
+                $file = "pico.$color$min.css";
+                break;
+            case '6':
+                $file = "pico.classless.$color$min.css";
+                break;
+            case '7':
+                $file = "pico.conditional.$color$min.css";
+                break;
+            case '8':
+                $file = "pico.fluid.classless.conditional.$color$min.css";
+                break;
+            case '9':
+                $file = "pico.colors$min.css";
+                break;
+            default:
+                $file = "pico$min.css";
+                break;
         }
 
         $url = $base . $file;
         $dest = __DIR__ . '/../../public/assets/css/sprout.min.css';
 
         self::download($url, $dest);
+
+        // Prompt for dark/light mode toggle
+        echo "\nWould you like to include a dark/light mode toggle button in your navbar? (y/N): ";
+        $includeToggle = strtolower(trim(fgets(STDIN)));
+        if ($includeToggle === 'y') {
+            $navbarPath = __DIR__ . '/../../app/Views/components/navbar.twig';
+            $navbar = file_get_contents($navbarPath);
+            // Only add if not already present
+            if (strpos($navbar, 'theme-toggle-btn') === false) {
+                $toggleBtn = <<<HTML
+                            <li>
+                            <!-- Dark/Light mode toggle auto-included by SproutPHP installer -->
+                            <button id="theme-toggle-btn" aria-label="Toggle dark/light mode" style="background:none;border:none;cursor:pointer;font-size:1.5rem;">
+                                <span id="theme-icon">☀️</span>
+                            </button>
+                            </li>
+                            HTML;
+                // Insert before </ul> of the right-side nav (last </ul> in file)
+                $navbar = preg_replace('/(<\/ul>)(?![\s\S]*<\/ul>)/', "$toggleBtn\n$1", $navbar, 1);
+                // Add the script before </div> at the end
+                $toggleScript = <<<SCRIPT
+                                <script>
+                                (function() {
+                                const themeBtn = document.getElementById('theme-toggle-btn');
+                                const themeIcon = document.getElementById('theme-icon');
+                                const html = document.documentElement;
+                                if (!themeBtn || !themeIcon) return;
+                                function setInitialTheme() {
+                                    let theme = localStorage.getItem('theme');
+                                    if (!theme) {
+                                    theme = window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light';
+                                    }
+                                    html.setAttribute('data-theme', theme);
+                                    themeIcon.textContent = theme === 'dark' ? '🌙' : '☀️';
+                                }
+                                setInitialTheme();
+                                themeBtn.addEventListener('click', function() {
+                                    const currentTheme = html.getAttribute('data-theme');
+                                    const newTheme = currentTheme === 'dark' ? 'light' : 'dark';
+                                    html.setAttribute('data-theme', newTheme);
+                                    localStorage.setItem('theme', newTheme);
+                                    themeIcon.textContent = newTheme === 'dark' ? '🌙' : '☀️';
+                                });
+                                })();
+                                </script>
+                                SCRIPT;
+                $navbar = preg_replace('/<\/div>\s*$/', "$toggleScript\n</div>", $navbar, 1);
+                file_put_contents($navbarPath, $navbar);
+                echo "✅ Dark/light mode toggle added to your navbar.\n";
+            } else {
+                echo "ℹ️  Dark/light mode toggle already present in your navbar.\n";
+            }
+        } else {
+            echo "ℹ️  You can add a dark/light mode toggle later by yourself if you wish.\n";
+        }
     }
 }