diff --git a/Jellyfin.Plugin.Seasonals/Web/test-site-new.html b/Jellyfin.Plugin.Seasonals/Web/test-site-new.html
index 627ce68..88d9db7 100644
--- a/Jellyfin.Plugin.Seasonals/Web/test-site-new.html
+++ b/Jellyfin.Plugin.Seasonals/Web/test-site-new.html
@@ -370,9 +370,69 @@
             console.log('[Test Site] Theme cleared.');
         }
 
+        // Track active animation frames and observers for cleanup
+        let activeAnimationFrames = [];
+        let activeBlobUrls = [];
+
+        // Patch requestAnimationFrame and MutationObserver to track them
+        const origRAF = window.requestAnimationFrame;
+        const origCAF = window.cancelAnimationFrame;
+        let trackingEnabled = false;
+
+        window.requestAnimationFrame = function(cb) {
+            const id = origRAF.call(window, cb);
+            if (trackingEnabled) activeAnimationFrames.push(id);
+            return id;
+        };
+
+        window.cancelAnimationFrame = function(id) {
+            origCAF.call(window, id);
+            activeAnimationFrames = activeAnimationFrames.filter(f => f !== id);
+        };
+
+        // Track MutationObservers created by themes
+        let activeObservers = [];
+        const OrigMO = window.MutationObserver;
+        window.MutationObserver = class extends OrigMO {
+            constructor(cb) {
+                super(cb);
+                if (trackingEnabled) activeObservers.push(this);
+            }
+        };
+
+        // Track intervals created by themes
+        let activeIntervals = [];
+        const origSetInterval = window.setInterval;
+        const origClearInterval = window.clearInterval;
+        window.setInterval = function(...args) {
+            const id = origSetInterval.apply(window, args);
+            if (trackingEnabled) activeIntervals.push(id);
+            return id;
+        };
+        window.clearInterval = function(id) {
+            origClearInterval.call(window, id);
+            activeIntervals = activeIntervals.filter(i => i !== id);
+        };
+
         function loadTheme() {
             clearTheme();
 
+            // Cancel all tracked animation frames
+            activeAnimationFrames.forEach(id => origCAF.call(window, id));
+            activeAnimationFrames = [];
+
+            // Disconnect all tracked MutationObservers
+            activeObservers.forEach(obs => obs.disconnect());
+            activeObservers = [];
+
+            // Clear all tracked intervals
+            activeIntervals.forEach(id => origClearInterval.call(window, id));
+            activeIntervals = [];
+
+            // Revoke old blob URLs
+            activeBlobUrls.forEach(url => URL.revokeObjectURL(url));
+            activeBlobUrls = [];
+
             const value = select.value;
             if (!value || value === '') return;
 
@@ -403,16 +463,31 @@
                 document.head.appendChild(link);
             }
 
-            // Inject JS (after a short delay to let CSS load)
+            // Inject JS wrapped in IIFE to avoid const redeclaration errors
             if (jsFile) {
-                setTimeout(() => {
-                    const script = document.createElement('script');
-                    script.src = jsFile;
-                    script.setAttribute('data-seasonal', 'true');
-                    script.onerror = () => console.error(`[Test Site] Failed to load JS: ${jsFile}`);
-                    document.body.appendChild(script);
-                    console.log(`[Test Site] Loaded theme: ${value} (${jsFile})`);
-                }, 100);
+                setTimeout(async () => {
+                    try {
+                        const response = await fetch(jsFile);
+                        if (!response.ok) throw new Error(`HTTP ${response.status}`);
+                        const code = await response.text();
+
+                        // Wrap in IIFE so each theme has its own scope
+                        const wrappedCode = `(function() {\n${code}\n})();`;
+                        const blob = new Blob([wrappedCode], { type: 'application/javascript' });
+                        const blobUrl = URL.createObjectURL(blob);
+                        activeBlobUrls.push(blobUrl);
+
+                        trackingEnabled = true;
+                        const script = document.createElement('script');
+                        script.src = blobUrl;
+                        script.setAttribute('data-seasonal', 'true');
+                        script.onerror = () => console.error(`[Test Site] Failed to execute JS: ${jsFile}`);
+                        document.body.appendChild(script);
+                        console.log(`[Test Site] Loaded theme: ${value} (${jsFile}) [IIFE-wrapped]`);
+                    } catch (err) {
+                        console.error(`[Test Site] Failed to load JS: ${jsFile}`, err);
+                    }
+                }, 150);
             }
         }
     </script>