diff --git a/config/prod/config.php b/config/prod/config.php
new file mode 100644
index 0000000..bc2b204
--- /dev/null
+++ b/config/prod/config.php
@@ -0,0 +1,4 @@
+<?php
+
+// Für STAGING / DEV:
+define('ASSET_VERSION', "v1"); // Oder '2025-11-21-dev'
\ No newline at end of file
diff --git a/config/prod/fileload.php b/config/prod/fileload.php
new file mode 100644
index 0000000..ac5eada
--- /dev/null
+++ b/config/prod/fileload.php
@@ -0,0 +1,5 @@
+<?php
+
+require  __DIR__ . "/config.php";
+require  __DIR__ . "/db.php";
+require __DIR__ . '/../src/functions.php';
diff --git a/config/staging/config.php b/config/staging/config.php
new file mode 100644
index 0000000..225b6d1
--- /dev/null
+++ b/config/staging/config.php
@@ -0,0 +1,4 @@
+<?php
+
+// Für STAGING / DEV:
+define('ASSET_VERSION', time()); // Oder '2025-11-21-dev'
\ No newline at end of file
diff --git a/config/staging/fileload.php b/config/staging/fileload.php
new file mode 100644
index 0000000..be10a91
--- /dev/null
+++ b/config/staging/fileload.php
@@ -0,0 +1,7 @@
+<?php
+ini_set('display_errors', 1);
+ini_set('display_startup_errors', 1);
+error_reporting(E_ALL);
+require  __DIR__ . "/config.php";
+require  __DIR__ . "/db.php";
+require __DIR__ . '/../src/functions.php';
diff --git a/partials/structure/layout_end.php b/partials/structure/layout_end.php
index a9d8b09..fee4c6c 100644
--- a/partials/structure/layout_end.php
+++ b/partials/structure/layout_end.php
@@ -9,6 +9,41 @@
     ?>
 
 </div>
+<?php
+// CSS im Footer (falls benötigt)
+foreach ($GLOBALS['page_styles'] as $style) {
+    if ($style['pos'] !== 'footer') {
+        continue;
+    }
+
+    $href = $style['href'];
+    if (!empty($style['version'])) {
+        $href .= (str_contains($href, '?') ? '&' : '?') . 'v=' . urlencode($style['version']);
+    }
+
+    echo '<link rel="stylesheet" href="' . htmlspecialchars($href) . '">' . PHP_EOL;
+}
+
+// Scripts im Footer
+foreach ($GLOBALS['page_footer_scripts'] as $script) {
+    $src = $script['src'];
+    if (!empty($script['version'])) {
+        $src .= (str_contains($src, '?') ? '&' : '?') . 'v=' . urlencode($script['version']);
+    }
+
+    $attr = '';
+    if ($script['async']) {
+        $attr .= ' async';
+    } elseif ($script['defer']) {
+        $attr .= ' defer';
+    }
+    if ($script['type']) {
+        $attr .= ' type="' . htmlspecialchars($script['type']) . '"';
+    }
+
+    echo '<script src="' . htmlspecialchars($src) . '"' . $attr . '></script>' . PHP_EOL;
+}
+?>
 
 <!-- Globale JS-Dateien -->
 <script src="/assets/js/lang.js"></script>
diff --git a/partials/structure/layout_start.php b/partials/structure/layout_start.php
index 1e3e3fd..610e50c 100644
--- a/partials/structure/layout_start.php
+++ b/partials/structure/layout_start.php
@@ -38,6 +38,41 @@ $host = $_SERVER['HTTP_HOST'] ?? '';
     <link rel="preconnect" href="https://fonts.googleapis.com">
     <link rel="preconnect" href="https://fonts.gstatic.com" crossorigin>
     <link href="https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600&family=Montserrat:wght@600;700;800&display=swap" rel="stylesheet">
+<?php
+// CSS im Header
+foreach ($GLOBALS['page_styles'] as $style) {
+    if ($style['pos'] !== 'header') {
+        continue;
+    }
+
+    $href = $style['href'];
+    if (!empty($style['version'])) {
+        $href .= (str_contains($href, '?') ? '&' : '?') . 'v=' . urlencode($style['version']);
+    }
+
+    echo '<link rel="stylesheet" href="' . htmlspecialchars($href) . '">' . PHP_EOL;
+}
+
+// Scripts im Header
+foreach ($GLOBALS['page_header_scripts'] as $script) {
+    $src = $script['src'];
+    if (!empty($script['version'])) {
+        $src .= (str_contains($src, '?') ? '&' : '?') . 'v=' . urlencode($script['version']);
+    }
+
+    $attr = '';
+    if ($script['async']) {
+        $attr .= ' async';
+    } elseif ($script['defer']) {
+        $attr .= ' defer';
+    }
+    if ($script['type']) {
+        $attr .= ' type="' . htmlspecialchars($script['type']) . '"';
+    }
+
+    echo '<script src="' . htmlspecialchars($src) . '"' . $attr . '></script>' . PHP_EOL;
+}
+?>
 
     <!-- Tailwind (Dev) -->
     <script src="https://cdn.tailwindcss.com"></script>
diff --git a/public/assets/js/auth.js b/public/assets/js/auth.js
new file mode 100644
index 0000000..39eba4a
--- /dev/null
+++ b/public/assets/js/auth.js
@@ -0,0 +1,30 @@
+document.addEventListener("DOMContentLoaded", () => {
+    const tabs = document.querySelectorAll(".auth-tab");
+    const panelLogin = document.getElementById("authPanelLogin");
+    const panelRegister = document.getElementById("authPanelRegister");
+
+    if (!tabs.length || !panelLogin || !panelRegister) return;
+
+    tabs.forEach(tab => {
+        tab.addEventListener("click", () => {
+            const target = tab.getAttribute("data-tab"); // "login" oder "register"
+
+            // Tab-Styles
+            tabs.forEach(t => {
+                t.classList.remove("bg-brand-primary", "text-brand-bg");
+                t.classList.add("hover:text-brand-primary");
+            });
+            tab.classList.add("bg-brand-primary", "text-brand-bg");
+            tab.classList.remove("hover:text-brand-primary");
+
+            // Panels
+            if (target === "login") {
+                panelLogin.classList.remove("hidden");
+                panelRegister.classList.add("hidden");
+            } else {
+                panelRegister.classList.remove("hidden");
+                panelLogin.classList.add("hidden");
+            }
+        });
+    });
+});
diff --git a/public/fakecheck/index.php b/public/fakecheck/index.php
index 7bfd844..1431160 100644
--- a/public/fakecheck/index.php
+++ b/public/fakecheck/index.php
@@ -1,4 +1,7 @@
 <?php
+
+require  __DIR__ . "/../config/fileload.php";
+
 // public/fakecheck/index.php
 
 // Sprachlogik wie auf der Startseite
@@ -19,8 +22,6 @@ $navAnchors = [];
 $scheme  = (!empty($_SERVER['HTTPS']) && $_SERVER['HTTPS'] !== 'off') ? 'https' : 'http';
 $host    = $_SERVER['HTTP_HOST'] ?? 'usbcheck.it';
 $baseUrl = $scheme . '://' . $host;
-
-require __DIR__ . '/../../src/functions.php';
 $lang = $_GET['lang'] ?? 'en';
 $lang = in_array($lang, ['de','en','it','fr']) ? $lang : 'en';
 
diff --git a/public/index.php b/public/index.php
index c17c5be..6cff852 100644
--- a/public/index.php
+++ b/public/index.php
@@ -1,8 +1,6 @@
 <?php
-ini_set('display_errors', 1);
-ini_set('display_startup_errors', 1);
-error_reporting(E_ALL);
-require __DIR__ . '/../src/functions.php';
+require  __DIR__ . "/../config/fileload.php";
+
 
 // Sprachlogik:
 $lang = $_GET['lang'] ?? 'en';
diff --git a/public/login/index.php b/public/login/index.php
index da0d0e4..5e37a1d 100644
--- a/public/login/index.php
+++ b/public/login/index.php
@@ -1,10 +1,7 @@
 <?php
-ini_set('display_errors', 1);
-ini_set('display_startup_errors', 1);
-error_reporting(E_ALL);
-
-require __DIR__ . '/../../src/functions.php';
+require  __DIR__ . "/../config/fileload.php";
 
+tpl_add_script('/assets/js/auth.js', 'footer', true, false, '', 'auth-1');
 // Sprachlogik:
 $lang = $_GET['lang'] ?? 'en';
 $lang = in_array($lang, ['de','en','it','fr']) ? $lang : 'en';
diff --git a/src/functions.php b/src/functions.php
index 36f9c8b..437407c 100644
--- a/src/functions.php
+++ b/src/functions.php
@@ -1,4 +1,72 @@
 <?php
+
+<?php
+
+$GLOBALS['page_header_scripts'] = $GLOBALS['page_header_scripts'] ?? [];
+$GLOBALS['page_footer_scripts'] = $GLOBALS['page_footer_scripts'] ?? [];
+$GLOBALS['page_styles']         = $GLOBALS['page_styles'] ?? [];
+
+/**
+ * Script registrieren
+ *
+ * @param string      $src      Pfad zur Datei, z. B. '/assets/js/auth.js'
+ * @param string      $pos      'header' oder 'footer'
+ * @param bool        $defer    standard true
+ * @param bool        $async    standard false
+ * @param string      $type     z. B. 'module'
+ * @param string|null $version  null = nutze ASSET_VERSION (falls definiert),
+ *                              ''   = kein ?v=,
+ *                              'xyz'= erzwinge diese Version
+ */
+function tpl_add_script(
+    string $src,
+    string $pos = 'footer',
+    bool $defer = true,
+    bool $async = false,
+    string $type = '',
+    ?string $version = null
+): void {
+    // Standard-Verhalten: falls Version nicht explizit gesetzt → globale ASSET_VERSION verwenden
+    if ($version === null && defined('ASSET_VERSION')) {
+        $version = ASSET_VERSION;
+    }
+
+    $data = [
+        'src'     => $src,
+        'defer'   => $defer,
+        'async'   => $async,
+        'type'    => $type,
+        'version' => $version, // kann null, '' oder string sein
+    ];
+
+    if ($pos === 'header') {
+        $GLOBALS['page_header_scripts'][] = $data;
+    } else {
+        $GLOBALS['page_footer_scripts'][] = $data;
+    }
+}
+
+/**
+ * CSS registrieren
+ *
+ * @param string      $href     Pfad zur CSS
+ * @param string      $pos      'header' oder 'footer'
+ * @param string|null $version  gleiche Logik wie bei Scripts
+ */
+function tpl_add_style(string $href, string $pos = 'header', ?string $version = null): void
+{
+    if ($version === null && defined('ASSET_VERSION')) {
+        $version = ASSET_VERSION;
+    }
+
+    $GLOBALS['page_styles'][] = [
+        'href'    => $href,
+        'pos'     => $pos,
+        'version' => $version,
+    ];
+}
+
+
 /**
  * Templating Loader
  *