Replicate Shopify Theme Header/Footer

I’m running two separate Shopify themes. My goal is to keep the current working theme exactly as it is, but swap in the header, its menu behaviour, and the footer style taken from my second theme.

Here’s what I need done:

• Header: match the second theme’s logo placement, main navigation links layout, and integrated search bar exactly, both in appearance and behaviour.
• Menu behaviour: duplicate its dropdown structure, sticky navigation on scroll, and full-width mega menu formatting.
• Footer: carry over only the footer navigation links section, preserving its styling and link hierarchy.

Everything else—product pages, collection templates, section settings, theme settings, and any liquid or CSS unrelated to the header/menu/footer—should remain untouched so I can keep my existing customisations intact.

Acceptance criteria
• Visual match between themes for the elements listed above on desktop and mobile breakpoints.
• No console errors or broken links introduced.
• All edits isolated to a child copy or clearly commented code so I can revert if needed.

I can provide theme zip files or collaborator access. Let me know how quickly you can turn this around and any questions you might have about the reference theme structure.