Mobile Contact Search Webpage

I need a lightweight, minimalist single-page web app that reads an existing Excel contact list, runs full-text search on first and/or last name (partial strings included), and is laid out for phone use in landscape mode.

When a visitor finds the right record, they tap an “INTERESTED” button beside it. A small text field then appears so they can leave a comment. On submission, the contact’s details plus the comment are written to a separate list (a new Excel sheet, CSV, or JSON file—whatever is easiest to maintain). No user login or authentication is required; the page should open directly and be ready to search.

Deliverables:
• Clean HTML, CSS, and JavaScript (or a concise framework) implementing the search, “Interested” action, and data capture
• A short script or helper utility that imports the original Excel file and handles the write-back of comments to the secondary list
• Brief setup notes so I can drop the files onto a basic web host or local server and start using the page immediately

Acceptance: the page loads in under two seconds on a modern phone, search is responsive as I type, and every submitted comment reliably appears in the separate list with a timestamp.