Bubble tea franchise breakeven-cups calculator tool - rent, labor, and HQ monthly fees into fixed costs; ingredient cost ratio taken as "last 3 months purchases / sales," never the franchisor's theoretical figure; in-store and delivery computed as separate lines, plus a three-row sensitivity table and cash runway

You are a coding agent building a tool for a bubble
tea franchisee. Build a single-file HTML tool
(HTML/CSS/JS fully inline, no external dependencies,
no network requests, opens by double-click) that
computes a store's breakeven cups and cash runway.

Computation logic (bake into the tool):
- Fixed cost per month = rent + labor + utilities +
  HQ monthly fixed fees (management / system) +
  debt service if any
- Variable costs, two lines:
  in-store line = average ticket x ingredient cost
  ratio
  delivery line = average ticket x (ingredient cost
  ratio + platform commission and promo cost-share
  rate)
  All rates are typed by the owner; input boxes start
  empty - never pre-fill "typical industry values"
- The ingredient cost ratio's sourcing rule is
  printed beside its input box, fixed: last three
  months' purchases / sales (purchases exclude
  equipment) - the franchisor's theoretical cost
  ratio is banned; theory and reality never match
- Breakeven cups = monthly fixed cost / weighted
  margin per cup (weighted by the in-store /
  delivery order split, which the owner enters)
- Cash runway = available cash / recent monthly net
  outflow (owner enters the actual recent figure;
  if net outflow is negative, show "profitable this
  month - not applicable")

Input area:
- Fixed costs line by line, both lines' tickets and
  cost rates, order split, available cash, recent
  monthly net outflow, 7-day average daily cups
- Every figure editable, instant recalculation on
  change

Output area:
- Daily breakeven cups (monthly breakeven / trading
  days this month) side by side with the 7-day
  average; the gap is the daily shortfall or surplus
- Three tiers: average >= breakeven -> green;
  between 0.9 x breakeven and breakeven -> yellow;
  below 0.9 x breakeven -> red. Red permanently
  displays one line: "Two straight weeks in red:
  move the biggest fixed cost first (whichever of
  rent / labor / HQ fees is largest) - do not cut
  prices first; a price cut hits margin and the
  breakeven line at both ends"
- Sensitivity table (three fixed rows): ticket -1 /
  ingredient cost ratio +2 points / rent negotiated
  down 10% - where each pushes daily breakeven cups
- "Export one-page summary" button: plain text,
  the version for a partner or family member

Constraints:
- No accounts, no network, no cloud - financial data
  lives in browser localStorage, with a one-click
  wipe
- Any empty input renders "pending" in the output -
  never compute on zero or the previous value. One
  wrong breakeven line makes every decision after
  it wrong.
- The tool produces numbers only, never "revenue
  growth advice" - the owner's moves are not the
  tool's business
- Usable one-handed on a phone in portrait (the
  owner opens it in the store), body text no
  smaller than 16px

Why it is written this way

Splitting in-store and delivery into two lines exists because their cost structures differ at the root: the same cup eats only ingredients in-store but also commission and promo cost-share on delivery. A blended "average cost ratio" yields a breakeven line that reads low for delivery-heavy stores and high for in-store-heavy ones - wrong at both ends, and a breakeven line's entire value is being believed.

Forcing the ingredient cost ratio to "last three months' purchases / sales" and banning the franchisor's theoretical figure addresses a franchise-specific trap. The ratio on the recruitment projection is an ideal recipe value with no waste, no spoilage, no promo give-away - and the gap between it and reality can swallow the entire profit. The tool cannot make the ratio accurate, but it can nail the sourcing convention next to the input box so that someone about to type "about 35%" pauses for a second.

The sensitivity table is exactly three fixed rows, by deliberate restraint. The classic red-tier mistake is cutting prices to chase volume - which slashes ticket and margin simultaneously and pushes the breakeven line up. Three rows of sensitivity put "which lever moves the line, and by how much" in one view, more direct than any advice. The one fixed sentence in the red tier is the tool's only piece of "talk": it does not decide for the owner, it just marks the most common wrong road.

"Pending, never defaulted" is the honesty floor shared by every reconciliation tool: a breakeven line computed on zeroed inputs still produces output, all of it wrong - and once a tool has helped its user balance the books wrong even once, none of its lines get believed again.

Variables