Build me a simple web app I can open on my phone: a bill splitter for 5 friends after dinner.
- I can type the 5 names and how much each person actually paid.
- I can add the items we ordered with prices, and tick who shared each item (default: everyone).
- I can add tip % and tax %, split proportionally to what each person ate.
- Show what each person owes and the fewest payments needed to settle up ("Anna pays Ben €12.30").
- Handle cents correctly so the totals add up exactly.
- Everything stays on my phone: no login, no saving data online.
Make it a single page that works when I open it.