diff --git a/src/shared/lib/helpers/createVirtualizer/createVirtualizer.svelte.ts b/src/shared/lib/helpers/createVirtualizer/createVirtualizer.svelte.ts
index 7e68bdd..d1faa3e 100644
--- a/src/shared/lib/helpers/createVirtualizer/createVirtualizer.svelte.ts
+++ b/src/shared/lib/helpers/createVirtualizer/createVirtualizer.svelte.ts
@@ -258,12 +258,13 @@ export function createVirtualizer<T>(
             // Calculate initial offset ONCE
             const getElementOffset = () => {
                 const rect = node.getBoundingClientRect();
-                return rect.top + window.scrollY;
+                const scrollY = typeof window !== 'undefined' ? window.scrollY : 0;
+                return rect.top + scrollY;
             };
 
             let cachedOffsetTop = 0;
             let rafId: number | null = null;
-            containerHeight = window.innerHeight;
+            containerHeight = typeof window !== 'undefined' ? window.innerHeight : 0;
 
             const handleScroll = () => {
                 if (rafId !== null) {