Tobacco & liquor store owner - festival stocking capital calculator - single-file web page, last year's festival sales in, this year's stocking capital need, funding gap, and post-festival carryover out, with returnable and non-returnable stock risk split into two columns

You are a coding agent building a tool for a tobacco
& liquor store owner. Build a single-file HTML tool
(all inline, no external dependencies, no network
calls, opens by double-click): a festival stocking
capital calculator.

The owner's problem, stated in the tool's
positioning: the year is won or lost across two
festival seasons, and stocking for them swallows
most of the year's capital. Under-stock and you
run dry mid-festival and lose the big orders;
over-stock and the carryover sits until next
season - a single pallet of premium bottles can
tie up what an ordinary shop does in a day of
sales. This cannot be decided by gut.

Input section (one set per festival, switchable
on the same page):
- Last year's festival sales by category:
  cigarettes / premium liquor / everyday
  liquor / beverages and sundries; two prior
  years is better than one
- Locked demand this year: confirmed corporate
  orders, wedding intentions (count x estimated
  value per event, with a haircut slider)
- Supplier policies, one entry each: cash-only
  non-returnable / returnable at cost after the
  festival (what percentage) / volume rebate
  (threshold and rate)
- Capital side: available own funds, the working
  reserve that must never be touched, credit
  line and rate if any

Calculations and output:
1. Three stocking plans side by side:
   conservative (locked demand plus a little
   walk-in), match-last-year, aggressive (last
   year plus an adjustable uplift percentage) -
   each showing stocking value by category,
   total capital need, and the gap against
   own funds
2. Returnable vs non-returnable columns: split
   the stocking value by supplier policy into
   "returnable after the festival" and
   "non-returnable" - returnable stock ties up
   cash but carries no carryover risk,
   non-returnable is the real exposure. Two
   columns, big numbers, never merged into one
   total
3. Post-festival carryover sensitivity: if actual
   festival sales land 5% / 10% / 20% under
   plan, how much stock sticks per category,
   and how many weeks of normal (off-season)
   sell-through it takes to digest - premium
   liquor flagged separately, because weeks
   stuck times unit price is the number that
   hurts
4. Cost of the gap: if the gap is financed,
   interest at the entered rate over the
   expected holding months, printed under the
   plan cards

Boundaries (printed on the page):
- No forecasting of this year's market - the
  tool does arithmetic, the human judges the
  market
- Volume rebates are discounted to what you
  actually expect to earn - a rebate whose
  threshold you won't reach is zero
- The working reserve is not available for
  stocking - raid it and you can't pay the
  weekly tobacco invoice mid-festival

Hard requirements:
- Data stays local (localStorage), exportable
  and resettable
- Both festivals on one page with a switch;
  preloaded sample data so results are visible
  on open; plan cards print cleanly

Why it is written this way

Splitting returnable from non-returnable into two columns is the tool's most important cut. Owners talk about stocking as one number - "I've bought 300k of goods" - but if 200k of it can go back to suppliers at cost after the festival, the risk profile is entirely different: returnable stock is a free option that costs interest, not losses; the non-returnable 100k is the actual bet. Merged into one total, the owner loses sleep over fake risk while ignoring the real one. Rebates get the same treatment - a three-point rebate behind a threshold you won't clear is worth zero, and planning against the headline rate is budgeting for a hallucination.

The carryover sensitivity table translates "I over-bought" into time. The hidden cost of over-stocking is never the invoice, it's the digestion period - after the festival, premium liquor sell-through drops to a fraction of normal, and "26 weeks to clear at current velocity" is what over-buying actually means. Premium liquor is flagged on its own row because weeks stuck must be multiplied by unit price to equal money stuck: ten weeks of premium bottles and ten weeks of beer look identical in unit counts and sit in different universes of capital.

The untouchable working reserve, written as a hard boundary, guards the most common way festival stocking goes wrong: the owner pours every yuan into liquor, and then the tobacco invoice, the utilities, and the rent come due mid-festival. Stock the shelves until daily operations suffocate and the cash chain snaps before the festival ends. Financing interest on the gap is printed under the plan cards rather than hidden, so the aggressive plan exposes its own price: does the extra stock's margin actually beat the extra interest plus carryover risk? One screen answers it.

Variables