Forty Two · Variables War / Core Duel

Based on Variables War by Kids Code Games.
Source: https://github.com/kids-code-games/variables-war/tree/36d4e1e2105eeb682830cf1ee1403993ba2a8513
License: Apache-2.0 (see LICENSE.txt).
Upstream GameRules.md, CardsDescription.md and card-maker/01_ourdeck/card.csv informed this adaptation.

Modified 2026-11-05: new static browser engine, interface, computer rival, save/undo and guided combo. No upstream code or images reused. Core deck counts retained from CSV: 53 signed values, 6 loops (player-count loop becomes x2), 20 attacks, 14 defenses. All seven bonus card types omitted. 93 cards total.

Digital clarifications: Firewall is a proactive next-attack reflection shield; Refactoring clears both board restrictions; Rollback restores the last card snapshot on the selected board (including effects), rather than reconstructing a physical card stack. Frozen counters tick down after the owner turn. Conditions check the final value after a Memory Leak. On an empty deck finish the current turn, then compare minimum absolute distances from 42. AI has access to its own hand and public board only.