init :)

index.js

@@ -0,0 +1,24 @@
+function hideHeaderOnScroll() {
+  const header = document.querySelector('header');
+  if (!header) return;
+
+  let lastScrollY = window.scrollY;
+  let offset = 0;
+  const headerHeight = header.offsetHeight;
+
+  function onScroll() {
+    const currentScroll = window.scrollY;
+    const diff = currentScroll - lastScrollY;
+
+    offset += diff;
+    offset = Math.max(0, Math.min(offset, headerHeight));
+
+    header.style.transform = `translateY(-${offset}px)`;
+
+    lastScrollY = currentScroll;
+  }
+
+  window.addEventListener('scroll', onScroll);
+}
+
+document.addEventListener('DOMContentLoaded', hideHeaderOnScroll);