:root {
  --ck-game-blue-900: #07356f;
  --ck-game-blue-800: #07559d;
  --ck-game-blue-700: #096fc5;
  --ck-game-blue-500: #1598ed;
  --ck-game-gold-900: #7a4205;
  --ck-game-gold-700: #b86a08;
  --ck-game-gold-500: #f4ac24;
  --ck-game-gold-300: #ffe08b;
  --ck-game-cream-100: #fff7df;
  --ck-game-cream-200: #ffe8aa;
  --ck-game-ink: #3f2b1c;
  --ck-game-muted: #7b6a54;
  --ck-game-green-600: #5fa923;
  --ck-game-green-400: #9bd957;
  --ck-game-violet-600: #7044b6;
  --ck-game-red-500: #e84d3d;
  --ck-game-surface: rgba(255, 247, 223, 0.96);
  --ck-game-border: #9f6110;
  --ck-game-shadow: 0 18px 40px rgba(82, 48, 7, 0.28);
  --ck-game-shadow-soft: 0 10px 24px rgba(54, 91, 122, 0.16);
  --ck-game-radius-sm: 8px;
  --ck-game-radius-md: 16px;
  --ck-game-radius-lg: 26px;
  --ck-game-font-display: "Baloo 2 Variable", "Baloo 2", "Nunito Sans Variable", "Nunito Sans", system-ui, sans-serif;
  --ck-game-font: "Nunito Sans Variable", "Nunito Sans", "Segoe UI", Arial, sans-serif;
  --ck-game-ui-font: "Nunito Sans Variable", "Nunito Sans", "Segoe UI", Arial, sans-serif;
  --ck-game-font-weight-copy: 600;
  --ck-game-font-weight-ui: 700;
  --ck-game-font-weight-strong: 800;
  --ck-game-stage-max: 1360px;
  --ck-game-safe-pad: clamp(14px, 2vw, 28px);
  --ck-game-motion-fast: 160ms;
  --ck-game-motion: 280ms;
  --ck-game-motion-slow: 520ms;

  /* Unified Theory / Practice semantic surfaces. */
  --ck-game-surface-hud: var(--ck-game-blue-900);
  --ck-game-surface-parchment: var(--ck-game-cream-100);
  --ck-game-surface-counter: rgba(255, 247, 223, 0.98);
  --ck-game-surface-lesson-active: var(--ck-game-blue-700);
  --ck-game-text-on-hud: var(--ck-game-cream-100);
  --ck-game-label-on-hud: var(--ck-game-gold-300);
  --ck-game-counter-text: var(--ck-game-blue-900);
  --ck-game-board-keyline: var(--ck-game-blue-900);
  --ck-game-board-corner: var(--ck-game-gold-500);

  /* Button plate faces mirror the approved raster interiors. */
  --ck-game-button-blue-face: #0269db;
  --ck-game-button-gold-face: #faaf01;
  --ck-game-button-green-face: #0ec68a;
  --ck-game-button-red-face: #fb4640;
  --ck-game-button-violet-face: #8741f1;
  --ck-game-button-stone-face: #bab8b7;
  --ck-game-button-shadow: 0 4px 0 rgba(47, 31, 13, 0.72), 0 9px 18px rgba(34, 24, 13, 0.22);
  --ck-game-button-shadow-pressed: 0 1px 0 rgba(47, 31, 13, 0.72), 0 4px 10px rgba(34, 24, 13, 0.18);
  --ck-game-focus-cream: var(--ck-game-cream-100);
  --ck-game-focus-blue: var(--ck-game-blue-700);

  /* Stable component geometry. */
  --ck-game-control-icon: 48px;
  --ck-game-control-height: 52px;
  --ck-game-control-cta: 64px;
  --ck-game-touch-gap: 8px;
  --ck-game-safe-bottom: 16px;
  --ck-game-toolbar-height: 52px;
  --ck-game-dock-height: 72px;
  --ck-game-feedback-height: 88px;

  /* Feedback is always icon + copy; color is secondary meaning. */
  --ck-game-feedback-info-bg: #eaf5ff;
  --ck-game-feedback-info-border: var(--ck-game-blue-700);
  --ck-game-feedback-info-text: #244e7a;
  --ck-game-feedback-hint-bg: var(--ck-game-cream-100);
  --ck-game-feedback-hint-border: var(--ck-game-gold-500);
  --ck-game-feedback-hint-text: #5a3b16;
  --ck-game-feedback-correct-bg: #edf8d8;
  --ck-game-feedback-correct-border: var(--ck-game-green-600);
  --ck-game-feedback-correct-text: #315d20;
  --ck-game-feedback-wrong-bg: #fff0e8;
  --ck-game-feedback-wrong-border: var(--ck-game-red-500);
  --ck-game-feedback-wrong-text: #7a2e22;

  /* One documented layer stack for every board surface. */
  --ck-game-z-hud: 12000;
  --ck-game-z-settings: 20000;
  --ck-game-z-reward: 21000;
  --ck-game-z-first-run: 22000;

  --cktg-blue-dark: var(--ck-game-blue-900);
  --cktg-blue: var(--ck-game-blue-700);
  --cktg-gold-dark: var(--ck-game-gold-900);
  --cktg-gold: var(--ck-game-gold-500);
  --cktg-cream: var(--ck-game-cream-100);
  --cktg-ink: var(--ck-game-ink);
}

/* ============================================================
   UI v2 — theme "spec2" flat-comic (Master Spec V2.0).
   Giá trị KHOÁ theo Style Lock V1 đã duyệt (sample từ
   output/imagegen/master_spec_v2_flat_comic/preview_00_style_lock_approved_v1.png).
   Chỉ theme spec2 (prefix tg2-) tiêu thụ nhóm token này.
   ============================================================ */
:root {
  /* Nét viền flat-comic: art nhân vật dày hơn, UI mỏng hơn (spec §2). */
  --ck-game-outline: #4a2f1d;
  --ck-game-outline-w: 3px;
  --ck-game-outline-w-ui: 2px;

  /* Chất liệu spec2 */
  --ck-game-wood-700: #6b4423;
  --ck-game-wood-500: #8a5a2e;
  --ck-game-wood-300: #b07a42;
  --ck-game-brass-600: #a97e2f;
  --ck-game-brass-400: #d9a93f;
  --ck-game-parchment-100: #f8ecce;
  --ck-game-parchment-200: #f0d9a6;
  --ck-game-parchment-border: #c8965a;
  --ck-game-terracotta-500: #c96f43;
  --ck-game-leaf-600: #6da621;
  --ck-game-leaf-500: #8ebb31;
  --ck-game-sky-400: #7fc4ef;

  /* CTA spec2 (đổ khối 2-3 tông + lip dưới, KHÔNG bevel sâu) */
  --ck-game-cta-orange-top: #fb911f;
  --ck-game-cta-orange: #f07514;
  --ck-game-cta-orange-lip: #c2570f;
  --ck-game-cta-green-top: #8ebb31;
  --ck-game-cta-green: #6da621;
  --ck-game-cta-green-lip: #4d7f16;
  --ck-game-chip-gold: #fcc728;
  --ck-game-chip-gold-deep: #d8960f;
  --ck-game-badge-red: #d92f2f;

  /* Kênh BIOME — biome CHỈ được override nhóm --ck-biome-* này
     (màu nền/viền/accent/fx). Geometry/radius/shadow nằm ngoài kênh:
     đổi biome KHÔNG trôi kích thước (spec Wave M3). Default = Forest. */
  --ck-biome-accent: var(--ck-game-leaf-500);
  --ck-biome-trim: var(--ck-game-wood-700);
  --ck-biome-sky: var(--ck-game-sky-400);
  --ck-biome-ground: #96b135;
  --ck-biome-board-light: #f2e3c2;
  --ck-biome-board-dark: #b98756;
  --ck-biome-fx: rgba(142, 187, 49, 0.35);
}

[data-ck-biome='ocean'] {
  --ck-biome-accent: #2e9fd0;
  --ck-biome-trim: #2c5d78;
  --ck-biome-sky: #8ed4f2;
  --ck-biome-ground: #fbcf81;
  --ck-biome-board-light: #f5e6c0;
  --ck-biome-board-dark: #4f9ab8;
  --ck-biome-fx: rgba(46, 159, 208, 0.35);
}

[data-ck-biome='ice'] {
  --ck-biome-accent: #7fd0e8;
  --ck-biome-trim: #4f7f96;
  --ck-biome-sky: #d9edf0;
  --ck-biome-ground: #e8f4f6;
  --ck-biome-board-light: #eef7f9;
  --ck-biome-board-dark: #8fb9c9;
  --ck-biome-fx: rgba(127, 208, 232, 0.4);
}

[data-ck-biome='volcano'] {
  --ck-biome-accent: #e8683a;
  --ck-biome-trim: #593c34;
  --ck-biome-sky: #f0a86a;
  --ck-biome-ground: #6b4a40;
  --ck-biome-board-light: #ecd2b0;
  --ck-biome-board-dark: #8a5644;
  --ck-biome-fx: rgba(232, 104, 58, 0.38);
}

@media (prefers-reduced-motion: reduce) {
  :root {
    --ck-game-motion-fast: 1ms;
    --ck-game-motion: 1ms;
    --ck-game-motion-slow: 1ms;
  }
}