zunda_shiwake/README.md

# Chick Sorter v16.1 Card Target Overlay Fix

This build refines the v15 card and tax system.

## v16.1 changes
- Fixed equipment improvement target-picking overlay by importing the target bounds helper into the renderer.
- Non-candidate equipment now receives a full dark overlay, and valid upgrade candidates are explicitly white-highlighted.
- Added a fallback message when a target picker has no valid target, so the game no longer appears frozen.

## v16 changes

- `Extra Cards` is now immediate.
  - Selecting it consumes the current card pick, then grants 2 more card selections in the same draft.
  - It no longer increases future draft size.
- Equipment improvement cards now target machines on the map.
  - Valid targets are highlighted in white.
  - Non-target areas are darkened.
  - Click a highlighted machine to apply the upgrade.
  - `Esc` cancels target selection and returns to the card draft.
- ZUNDA TAX and Fairies tribute no longer contaminate the next day’s profit display.
  - They are still paid when `Next Day` is pressed.
  - They still affect cash and total outflow.
  - They are not counted inside the new day’s `Turn Profit`.
- ZUNDA TAX exemption / Legal Work behavior was rechecked and kept explicit.
  - Base exemption: ￥500.
  - `Legal Work`: exemption +￥250 and 95% cap point +￥250.
  - Tax rate: 5% from the first yen above the exemption.
  - +5% per ￥500 taxable band.
  - Maximum rate: 95%.
- EGG FARM price remains ￥250.

## Active ZUNDA TAX formula

```text
taxable = max(0, cash - exemption)
rate = min(95%, ceil(taxable / 500) × 5%)
ZUNDA TAX = ceil(taxable × rate)
```

With no `Legal Work`, `exemption = ￥500`, so ￥501 starts at 5% and ￥10,000 reaches 95%.