/* =============================================================================
   ILS Decimal CSS — Styles for decimal visuals & interactions (Chapter 8)
   Companion to ils-decimal.js | v1.0
   Prefix: dec-

   Sections:
     1.  CSS Custom Properties (light / dark)
     2.  Hundredths Grid (.dec-grid)
     3.  Tenths Strip (.dec-strip)
     4.  Decimal Display (.dec-display, .dec-digit)
     5.  Place Value Table (.dec-pv-table)
     6.  Number Line (.dec-numline)
     7.  Money Display (.dec-money)
     8.  Conversion Display (.dec-convert)
     9.  Column Arithmetic (.dec-col-arith)
    10.  Comparison Layout (.dec-compare)
    11.  Visual Row / Column (.dec-visual-row, .dec-visual-col)
    12.  Dark Mode overrides
    13.  Responsive — 480px
    14.  Responsive — 360px
   ============================================================================= */


/* =============================================================================
   1. CSS CUSTOM PROPERTIES
   ============================================================================= */

#game-root {
  --dec-shaded: #6366f1;
  --dec-shaded-light: #818cf8;
  --dec-empty: #e2e8f0;
  --dec-text: #1e293b;
  --dec-text-muted: #64748b;
  --dec-bg-card: #ffffff;
  --dec-border: #cbd5e1;
  --dec-grid-stroke: #94a3b8;
  --dec-highlight-bg: #eef2ff;
  --dec-highlight-border: #6366f1;
  --dec-correct: #16a34a;
  --dec-correct-bg: #dcfce7;
  --dec-correct-border: #86efac;
  --dec-wrong: #dc2626;
  --dec-wrong-bg: #fee2e2;
  --dec-wrong-border: #fca5a5;
  --dec-nl-stroke: #475569;
  --dec-nl-text: #475569;

  /* Place-value digit colors */
  --dec-color-thousands: #7c3aed;
  --dec-color-hundreds: #9333ea;
  --dec-color-tens: #2563eb;
  --dec-color-ones: #0891b2;
  --dec-color-point: #1e293b;
  --dec-color-tenths: #059669;
  --dec-color-hundredths: #d97706;
  --dec-color-thousandths: #dc2626;

  /* Money */
  --dec-money-bg: #fffbeb;
  --dec-money-border: #fbbf24;
  --dec-rupee-color: #92400e;

  /* Column arithmetic */
  --dec-col-bg: #f8fafc;
  --dec-col-border: #e2e8f0;
  --dec-col-line: #475569;
  --dec-col-carry-color: #dc2626;
  --dec-col-hl-bg: #eef2ff;

  /* Conversion */
  --dec-convert-arrow: #6366f1;
}


/* =============================================================================
   2. HUNDREDTHS GRID (.dec-grid)
   ============================================================================= */

.dec-grid {
  display: inline-block;
  vertical-align: middle;
  line-height: 0;
}

.dec-grid svg {
  display: block;
  max-width: 100%;
  height: auto;
}

.dec-grid rect[data-cell] {
  transition: fill 0.15s ease;
}

.dec-grid rect[data-cell]:hover {
  filter: brightness(1.1);
  stroke-width: 1.5;
}


/* =============================================================================
   3. TENTHS STRIP (.dec-strip)
   ============================================================================= */

.dec-strip {
  display: inline-block;
  vertical-align: middle;
  line-height: 0;
}

.dec-strip svg {
  display: block;
  max-width: 100%;
  height: auto;
}

.dec-strip rect[data-strip-cell] {
  transition: fill 0.15s ease;
}

.dec-strip rect[data-strip-cell]:hover {
  filter: brightness(1.1);
}


/* =============================================================================
   4. DECIMAL DISPLAY (.dec-display, .dec-digit)
   ============================================================================= */

.dec-display {
  display: inline-flex;
  align-items: baseline;
  justify-content: center;
  vertical-align: middle;
  line-height: 1.2;
  font-weight: 700;
  color: var(--dec-text);
  user-select: none;
  gap: 1px;
}

.dec-digit {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  padding: 2px 4px;
  border-radius: 4px;
  transition: background 0.2s ease, color 0.2s ease, transform 0.2s ease;
  position: relative;
}

/* Place-value coloring */
.dec-digit-thousands  { color: var(--dec-color-thousands); }
.dec-digit-hundreds   { color: var(--dec-color-hundreds); }
.dec-digit-tens       { color: var(--dec-color-tens); }
.dec-digit-ones       { color: var(--dec-color-ones); }
.dec-digit-point      { color: var(--dec-color-point); font-weight: 900; padding: 2px 1px; }
.dec-digit-tenths     { color: var(--dec-color-tenths); }
.dec-digit-hundredths { color: var(--dec-color-hundredths); }
.dec-digit-thousandths { color: var(--dec-color-thousandths); }
.dec-digit-sign       { color: var(--dec-text); padding: 2px 2px 2px 0; }

/* Highlight state */
.dec-digit-hl {
  background: var(--dec-highlight-bg);
  border: 2px solid var(--dec-highlight-border);
  transform: scale(1.15);
  border-radius: 6px;
}

/* Place-value labels below digits */
.dec-pv-label {
  display: block;
  font-size: 0.55em;
  font-weight: 500;
  color: var(--dec-text-muted);
  margin-top: 1px;
  line-height: 1;
  letter-spacing: 0.02em;
}

/* ── Sizes ── */

.dec-sm { font-size: 16px; }
.dec-sm .dec-digit { padding: 1px 2px; }

.dec-md { font-size: 22px; }

.dec-lg { font-size: 32px; }
.dec-lg .dec-digit { padding: 3px 6px; }

.dec-xl { font-size: 42px; }
.dec-xl .dec-digit { padding: 4px 8px; }


/* =============================================================================
   5. PLACE VALUE TABLE (.dec-pv-table)
   ============================================================================= */

.dec-pv-table {
  display: inline-block;
  vertical-align: middle;
  margin: 8px 0;
}

.dec-pv-table table {
  border-collapse: collapse;
  border-spacing: 0;
  margin: 0 auto;
}

.dec-pv-table th,
.dec-pv-table td {
  text-align: center;
  padding: 6px 10px;
  border: 1.5px solid var(--dec-border);
  min-width: 2.2em;
  font-weight: 600;
}

/* Header row */
.dec-pv-header {
  font-size: 0.75em;
  font-weight: 700;
  letter-spacing: 0.03em;
  background: #f1f5f9;
  color: var(--dec-text-muted);
}

/* Colored headers matching digit colors */
.dec-pv-header.dec-digit-thousands  { color: var(--dec-color-thousands); background: #f5f3ff; }
.dec-pv-header.dec-digit-hundreds   { color: var(--dec-color-hundreds); background: #faf5ff; }
.dec-pv-header.dec-digit-tens       { color: var(--dec-color-tens); background: #eff6ff; }
.dec-pv-header.dec-digit-ones       { color: var(--dec-color-ones); background: #ecfeff; }
.dec-pv-header.dec-digit-tenths     { color: var(--dec-color-tenths); background: #ecfdf5; }
.dec-pv-header.dec-digit-hundredths { color: var(--dec-color-hundredths); background: #fffbeb; }
.dec-pv-header.dec-digit-thousandths { color: var(--dec-color-thousandths); background: #fef2f2; }

/* Decimal point column — narrow */
.dec-pv-point-header,
.dec-pv-point {
  min-width: auto;
  padding: 6px 4px;
  font-size: 1.1em;
  font-weight: 900;
  color: var(--dec-color-point);
  background: transparent;
  border-left-style: dashed;
  border-right-style: dashed;
}

/* Digit row */
.dec-pv-digit {
  font-size: 1.3em;
  font-weight: 700;
  background: var(--dec-bg-card);
}

/* Colored digits matching headers */
.dec-pv-digit.dec-digit-thousands  { color: var(--dec-color-thousands); }
.dec-pv-digit.dec-digit-hundreds   { color: var(--dec-color-hundreds); }
.dec-pv-digit.dec-digit-tens       { color: var(--dec-color-tens); }
.dec-pv-digit.dec-digit-ones       { color: var(--dec-color-ones); }
.dec-pv-digit.dec-digit-tenths     { color: var(--dec-color-tenths); }
.dec-pv-digit.dec-digit-hundredths { color: var(--dec-color-hundredths); }
.dec-pv-digit.dec-digit-thousandths { color: var(--dec-color-thousandths); }

/* Value row (×10, ×1, ×0.1, etc.) */
.dec-pv-value {
  font-size: 0.7em;
  font-weight: 500;
  color: var(--dec-text-muted);
  background: #f8fafc;
}

/* Highlight state */
.dec-pv-hl {
  background: var(--dec-highlight-bg) !important;
  border-color: var(--dec-highlight-border) !important;
  box-shadow: inset 0 0 0 1px var(--dec-highlight-border);
}


/* =============================================================================
   6. NUMBER LINE (.dec-numline)
   ============================================================================= */

.dec-numline {
  display: inline-block;
  vertical-align: middle;
  line-height: 0;
  margin: 8px 0;
}

.dec-numline svg {
  display: block;
  max-width: 100%;
  height: auto;
}

.dec-nl-label {
  user-select: none;
}

.dec-nl-label[data-nl-value] {
  cursor: pointer;
}

.dec-nl-label[data-nl-value]:hover {
  font-weight: 700 !important;
  fill: var(--dec-shaded) !important;
}

/* Pulse animation for highlighted points */
@keyframes dec-nl-pulse {
  0%, 100% { r: 5; opacity: 1; }
  50%      { r: 9; opacity: 0.6; }
}

.dec-nl-point-pulse {
  animation: dec-nl-pulse 1.2s ease-in-out infinite;
}


/* =============================================================================
   7. MONEY DISPLAY (.dec-money)
   ============================================================================= */

.dec-money {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  background: var(--dec-money-bg);
  border: 1.5px solid var(--dec-money-border);
  border-radius: 10px;
}

.dec-money-amount {
  font-size: 1.4em;
  font-weight: 700;
  color: var(--dec-rupee-color);
  letter-spacing: 0.02em;
}

.dec-rupee-symbol {
  font-weight: 800;
  margin-right: 2px;
}

.dec-money-coins {
  display: flex;
  flex-wrap: wrap;
  gap: 4px;
  justify-content: center;
  max-width: 280px;
}

.dec-coin,
.dec-note {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  font-size: 1.5em;
  padding: 2px;
  border-radius: 4px;
  position: relative;
  transition: transform 0.15s ease;
}

.dec-coin:hover,
.dec-note:hover {
  transform: scale(1.15);
}

.dec-coin-label {
  display: block;
  font-size: 0.4em;
  font-weight: 700;
  color: var(--dec-rupee-color);
  line-height: 1;
  margin-top: -2px;
}

.dec-coin-small {
  font-size: 1.2em;
  opacity: 0.85;
}

.dec-money-breakdown {
  font-size: 0.85em;
  color: var(--dec-text-muted);
  font-weight: 500;
  text-align: center;
  margin-top: 2px;
}

/* ── Money sizes ── */
.dec-money-sm { padding: 6px 10px; }
.dec-money-sm .dec-money-amount { font-size: 1.1em; }
.dec-money-sm .dec-coin, .dec-money-sm .dec-note { font-size: 1.2em; }

.dec-money-lg { padding: 14px 20px; }
.dec-money-lg .dec-money-amount { font-size: 1.8em; }
.dec-money-lg .dec-coin, .dec-money-lg .dec-note { font-size: 1.8em; }


/* =============================================================================
   8. CONVERSION DISPLAY (.dec-convert)
   ============================================================================= */

.dec-convert {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  background: #f0f9ff;
  border: 1.5px solid #bae6fd;
  border-radius: 10px;
}

.dec-convert-step {
  font-size: 1em;
  font-weight: 600;
  color: var(--dec-text);
  text-align: center;
}

.dec-convert-result {
  font-size: 1.2em;
  font-weight: 700;
}

.dec-convert-working {
  font-size: 0.9em;
  color: var(--dec-text-muted);
  font-style: italic;
}

.dec-convert-fraction {
  font-size: 0.9em;
  color: var(--dec-text-muted);
}

.dec-convert-from {
  color: var(--dec-color-ones);
  font-weight: 700;
}

.dec-convert-arrow {
  color: var(--dec-convert-arrow);
  font-weight: 800;
  margin: 0 6px;
}

.dec-convert-to {
  color: var(--dec-color-tenths);
  font-weight: 700;
}

/* KaTeX inside conversion */
.dec-convert .katex {
  font-size: inherit !important;
}


/* =============================================================================
   9. COLUMN ARITHMETIC (.dec-col-arith)
   ============================================================================= */

.dec-col-arith {
  display: inline-flex;
  flex-direction: column;
  align-items: stretch;
  background: var(--dec-col-bg);
  border: 1.5px solid var(--dec-col-border);
  border-radius: 10px;
  padding: 12px 16px;
  font-family: "Courier New", "Courier", monospace;
  font-size: 1.4em;
  line-height: 1;
  gap: 2px;
}

.dec-col-row {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0;
}

.dec-col-op {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.2em;
  font-weight: 700;
  color: var(--dec-shaded);
  flex-shrink: 0;
}

.dec-col-carry-space {
  /* Keep alignment when carry row has no operator */
}

.dec-col-digit {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 1.1em;
  height: 1.4em;
  font-weight: 700;
  color: var(--dec-text);
  text-align: center;
  border-radius: 3px;
  transition: background 0.2s ease, transform 0.2s ease;
}

.dec-col-point {
  width: 0.5em;
  font-weight: 900;
  color: var(--dec-color-point);
}

.dec-col-carry {
  font-size: 0.55em;
  color: var(--dec-col-carry-color);
  height: 1em;
  font-weight: 700;
  vertical-align: top;
}

/* Highlight column */
.dec-col-hl {
  background: var(--dec-col-hl-bg);
  border: 1.5px solid var(--dec-highlight-border);
  transform: scale(1.05);
}

/* Horizontal divider line */
.dec-col-line {
  height: 2px;
  background: var(--dec-col-line);
  margin: 4px 0;
  border-radius: 1px;
}

/* Result row */
.dec-col-result-row .dec-col-digit {
  color: var(--dec-correct);
  font-weight: 800;
}

/* Hidden digit (for step-by-step animation) */
.dec-col-hidden {
  visibility: hidden;
}

/* Carry row */
.dec-col-carry-row {
  min-height: 0.9em;
}


/* =============================================================================
   10. COMPARISON LAYOUT (.dec-compare)
   ============================================================================= */

.dec-compare {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  flex-wrap: wrap;
  padding: 8px 0;
}

.dec-compare-left,
.dec-compare-right {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  min-width: 100px;
}

.dec-compare-op {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 48px;
  height: 48px;
  border-radius: 12px;
  font-size: 1.5em;
  font-weight: 800;
  background: #f1f5f9;
  color: var(--dec-text);
  border: 2px solid var(--dec-border);
  user-select: none;
  flex-shrink: 0;
  transition: background 0.2s ease, border-color 0.2s ease, transform 0.15s ease;
}

.dec-compare-op-unknown {
  color: var(--dec-text-muted);
  background: #fef3c7;
  border-color: #fbbf24;
}

.dec-compare-op-interactive {
  cursor: pointer;
}

.dec-compare-op-interactive:hover {
  background: var(--dec-highlight-bg);
  border-color: var(--dec-highlight-border);
  transform: scale(1.08);
}

.dec-compare-op-interactive:active {
  transform: scale(0.96);
}

/* Correct / wrong states for comparison */
.dec-compare-op-correct {
  background: var(--dec-correct-bg);
  border-color: var(--dec-correct-border);
  color: var(--dec-correct);
}

.dec-compare-op-wrong {
  background: var(--dec-wrong-bg);
  border-color: var(--dec-wrong-border);
  color: var(--dec-wrong);
}


/* =============================================================================
   11. VISUAL ROW / COLUMN LAYOUT HELPERS
   ============================================================================= */

.dec-visual-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
  margin: 8px 0;
}

.dec-visual-row.dec-visual-wrap {
  flex-wrap: wrap;
}

.dec-visual-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

/* Center all decimal visuals inside common containers */
.dec-grid,
.dec-strip,
.dec-numline,
.dec-pv-table,
.dec-money,
.dec-convert,
.dec-col-arith,
.dec-compare {
  margin-left: auto;
  margin-right: auto;
}

/* KaTeX inside decimal containers — inherit size */
.dec-display .katex,
.dec-pv-table .katex,
.dec-col-arith .katex,
.dec-money .katex,
.dec-convert .katex,
.dec-compare .katex {
  font-size: inherit !important;
}


/* =============================================================================
   12. DARK MODE OVERRIDES
   ============================================================================= */

:root.dark #game-root,
.dark #game-root {
  --dec-shaded: #818cf8;
  --dec-shaded-light: #a5b4fc;
  --dec-empty: #334155;
  --dec-text: #e2e8f0;
  --dec-text-muted: #94a3b8;
  --dec-bg-card: #1e293b;
  --dec-border: #475569;
  --dec-grid-stroke: #64748b;
  --dec-highlight-bg: #312e81;
  --dec-highlight-border: #818cf8;
  --dec-correct: #4ade80;
  --dec-correct-bg: #14532d;
  --dec-correct-border: #22c55e;
  --dec-wrong: #f87171;
  --dec-wrong-bg: #7f1d1d;
  --dec-wrong-border: #ef4444;
  --dec-nl-stroke: #94a3b8;
  --dec-nl-text: #94a3b8;

  --dec-color-thousands: #a78bfa;
  --dec-color-hundreds: #c084fc;
  --dec-color-tens: #60a5fa;
  --dec-color-ones: #22d3ee;
  --dec-color-point: #e2e8f0;
  --dec-color-tenths: #34d399;
  --dec-color-hundredths: #fbbf24;
  --dec-color-thousandths: #f87171;

  --dec-money-bg: #422006;
  --dec-money-border: #92400e;
  --dec-rupee-color: #fbbf24;

  --dec-col-bg: #1e293b;
  --dec-col-border: #475569;
  --dec-col-line: #94a3b8;
  --dec-col-carry-color: #f87171;
  --dec-col-hl-bg: #312e81;

  --dec-convert-arrow: #818cf8;
}

/* Dark: PV table header backgrounds */
.dark .dec-pv-header {
  background: #1e293b;
}

.dark .dec-pv-header.dec-digit-thousands  { background: #2e1065; }
.dark .dec-pv-header.dec-digit-hundreds   { background: #3b0764; }
.dark .dec-pv-header.dec-digit-tens       { background: #1e3a5f; }
.dark .dec-pv-header.dec-digit-ones       { background: #164e63; }
.dark .dec-pv-header.dec-digit-tenths     { background: #064e3b; }
.dark .dec-pv-header.dec-digit-hundredths { background: #451a03; }
.dark .dec-pv-header.dec-digit-thousandths { background: #450a0a; }

/* Dark: PV table value row */
.dark .dec-pv-value {
  background: #0f172a;
}

/* Dark: Comparison operator */
.dark .dec-compare-op {
  background: #334155;
  border-color: #475569;
  color: var(--dec-text);
}

.dark .dec-compare-op-unknown {
  background: #451a03;
  border-color: #92400e;
  color: #fbbf24;
}

.dark .dec-compare-op-interactive:hover {
  background: var(--dec-highlight-bg);
  border-color: var(--dec-highlight-border);
}

/* Dark: Conversion display */
.dark .dec-convert {
  background: #0c4a6e;
  border-color: #0369a1;
}

/* Dark: Grid hover */
.dark .dec-grid rect[data-cell]:hover {
  filter: brightness(1.2);
}

/* Dark: Money coin labels */
.dark .dec-coin-label {
  color: var(--dec-rupee-color);
}

/* Dark: money breakdown text */
.dark .dec-money-breakdown {
  color: var(--dec-text-muted);
}


/* =============================================================================
   13. RESPONSIVE — 480px
   ============================================================================= */

@media (max-width: 480px) {

  /* Decimal display */
  .dec-md { font-size: 18px; }
  .dec-lg { font-size: 26px; }
  .dec-xl { font-size: 32px; }

  .dec-lg .dec-digit,
  .dec-xl .dec-digit {
    padding: 2px 4px;
  }

  /* PV table */
  .dec-pv-table th,
  .dec-pv-table td {
    padding: 4px 6px;
    font-size: 0.9em;
    min-width: 1.8em;
  }

  .dec-pv-header {
    font-size: 0.65em;
  }

  /* Number line */
  .dec-numline {
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    max-width: 100%;
  }

  .dec-numline svg {
    min-width: 320px;
  }

  /* Money */
  .dec-money {
    padding: 8px 10px;
  }

  .dec-money-coins {
    max-width: 220px;
    gap: 3px;
  }

  .dec-coin, .dec-note {
    font-size: 1.3em;
  }

  /* Column arithmetic */
  .dec-col-arith {
    font-size: 1.2em;
    padding: 10px 12px;
  }

  /* Conversion */
  .dec-convert {
    padding: 8px 12px;
  }

  .dec-convert-result {
    font-size: 1.05em;
  }

  /* Comparison */
  .dec-compare {
    gap: 10px;
  }

  .dec-compare-left,
  .dec-compare-right {
    min-width: 80px;
  }

  .dec-compare-op {
    width: 40px;
    height: 40px;
    font-size: 1.3em;
  }

  /* Visual rows */
  .dec-visual-row {
    gap: 8px;
  }
}


/* =============================================================================
   14. RESPONSIVE — 360px
   ============================================================================= */

@media (max-width: 360px) {

  /* Decimal display */
  .dec-md { font-size: 16px; }
  .dec-lg { font-size: 22px; }
  .dec-xl { font-size: 28px; }

  .dec-digit {
    padding: 1px 2px;
  }

  /* PV table */
  .dec-pv-table th,
  .dec-pv-table td {
    padding: 3px 4px;
    font-size: 0.8em;
    min-width: 1.5em;
  }

  .dec-pv-header {
    font-size: 0.55em;
    letter-spacing: 0;
  }

  .dec-pv-point-header,
  .dec-pv-point {
    padding: 3px 2px;
  }

  /* Number line */
  .dec-numline svg {
    min-width: 280px;
  }

  /* Money */
  .dec-money {
    padding: 6px 8px;
  }

  .dec-money-amount {
    font-size: 1.1em;
  }

  .dec-money-coins {
    max-width: 180px;
  }

  .dec-coin, .dec-note {
    font-size: 1.1em;
  }

  .dec-coin-label {
    font-size: 0.35em;
  }

  /* Column arithmetic */
  .dec-col-arith {
    font-size: 1em;
    padding: 8px 10px;
  }

  .dec-col-digit {
    width: 1em;
    height: 1.2em;
  }

  .dec-col-point {
    width: 0.4em;
  }

  .dec-col-op {
    width: 1em;
  }

  /* Conversion */
  .dec-convert {
    padding: 6px 10px;
    font-size: 0.9em;
  }

  /* Comparison — stack vertically */
  .dec-compare {
    flex-direction: column;
    gap: 8px;
  }

  .dec-compare-left,
  .dec-compare-right {
    min-width: auto;
  }

  .dec-compare-op {
    width: 36px;
    height: 36px;
    font-size: 1.2em;
    border-radius: 8px;
  }

  /* Visual rows stack */
  .dec-visual-row {
    flex-direction: column;
    gap: 6px;
  }
}