More deletes. Fixed sticky header.

hooks/useSticky.js

@@ -0,0 +1,27 @@
+import { useState, useEffect, useRef } from 'react';
+
+export default function useSticky(defaultSticky = false) {
+  const [isSticky, setIsSticky] = useState(defaultSticky);
+  const ref = useRef(null);
+  const initialTop = useRef(0);
+
+  useEffect(() => {
+    const handleScroll = () => {
+      if (window.pageYOffset > initialTop.current) {
+        setIsSticky(true);
+      } else {
+        setIsSticky(false);
+      }
+    };
+
+    initialTop.current = ref.current.offsetTop;
+
+    window.addEventListener('scroll', handleScroll);
+
+    return () => {
+      window.removeEventListener('scroll', handleScroll);
+    };
+  }, []);
+
+  return { ref, isSticky };
+}