The Via-nancial District 🗽🐀

A single-file, phone-first budgeting app for Via's two-week NYU trip to NYC (July 27 → August 9, 2026 · $1,800 + $30 dining dollars), narrated by Carlo "Slice" Ratigan, Chief Fiscal Rodent.

The entire app is index.html — no build, no dependencies, no server. All CSS/JS is inline so it can be published as a private claude.ai Artifact (which blocks all external requests) and opened straight from a phone's home screen.

How the budget works

• Daily allowance with rollover (cumulative carry). Available-today = round(total × dayNumber / tripDays) − everything spent through today. Underspend yesterday and today grows; overspend and it shrinks. It's a pure function of the expense list, so edits/backfills/date-changes recompute perfectly. A secondary pace stat shows what daily average lands the trip at exactly $0.
• Three categories, styled as subway line bullets: Eats (food & drinks), Fun (going out), Stuff (shopping & misc).
• Dining dollars are a separate mini-balance of $30 per week, use-it-or-lose-it (week 1 = Jul 27–Aug 2, week 2 = Aug 3–9). Flagged expenses draw from the week their date falls in, never the $1,800, and can't overdraw a week (one tap switches a blocked charge to the real budget).
• Day boundaries are America/New_York regardless of device timezone.
• All money is integer cents; the per-day allowances sum to exactly the total.
• Trip dates and totals are hardcoded by design (per Via) — Settings shows them read-only; only quick-add buttons and backups are editable.

The fun layer

• Carlo reacts: tap him for NYC wisdom (10 taps earn him a permanent crown); his accessories track budget health — sunglasses when flush, a sweat drop when wobbly, a grayed slice when today's overdrawn, a tiny violin when the trip is busted, a party hat on 3+ day under-budget streaks.
• Achievements: ten NYC badges (Dollar Slice Scholar, Bodega Baron, Museum Rat, Early Bird, Night Owl, The Untouchable, Streak Freak, Wall Street Energy, Meal Plan MVP, Sixth Borough) computed live from the expense log; unlocks toast + confetti + fanfare, shown on the Stats badge wall.
• Can I afford it? on Today: type a price, get slice-equivalents, what's left of today after buying, the new required pace, and a verdict.
• Split-by-N chips (÷2 ÷3 ÷4) under the amount field for group bills.
• Report cards: canvas-drawn 1080×1920 PNGs (day recap + trip report card) in a share overlay — long-press to save, or Download via the Artifact downloads API when available.
• Sounds (cha-ching / sad trombone / fanfare / squeak, synthesized, mutable in Settings), confetti (skipped under reduced-motion), and a once-a-day fake MTA service advisory keyed to yesterday's performance.

Data & backups

State auto-saves to localStorage (vianancial.v1, versioned schema) on every change. Storage failures degrade to in-memory mode with a warning banner. Data written by a newer schema than the page renders read-only rather than risking a wipe. Settings → Backups offers JSON export (via the Artifact downloads API, clipboard fallback), CSV export, and validated paste-to-import (with preview and an automatic .bak snapshot before replacing anything).

Tests

A dependency-free Playwright harness (uses the globally installed playwright package and the preinstalled Chromium):

NODE_PATH="$(npm root -g)" node tests/run-tests.cjs      # 15 behavioral tests
NODE_PATH="$(npm root -g)" node tests/screenshots.cjs    # renders every screen

The suite covers exact-cents rollover math, dining-dollar accounting, persistence across reload, edit/delete/undo, import/export round-trips, hostile-input rejection (including XSS-shaped notes), storage-failure and newer-schema guards, phase transitions, and both color themes. tests/seed.js re-implements the money math independently so tests never trust the app's own logic.

Hosting

The real app lives on GitHub Pages: https://viaate.github.io/olivify/ — auto-deployed by .github/workflows/pages.yml on every push to the default branch (the workflow self-enables Pages via actions/configure-pages). Pages is the canonical home because the claude.ai Artifact preview runs in a sandboxed frame that blocks all persistent storage — the app detects that and shows a banner pointing here instead. On Pages the app is a proper PWA: manifest.webmanifest + Carlo icons (regenerate with node tests/make-icons.cjs) + sw.js (network-first offline shell), and it requests navigator.storage.persist() to guard against eviction.

The same index.html still publishes as a claude.ai Artifact (it has no <!doctype>/<html>/<head>/<body> wrapper; the publisher adds one) — useful as a preview, not as the daily app.