/* =============================================================================
   ILS Fraction CSS — Styles for fraction visuals & interactions (Chapter 7)
   Companion to ils-fraction.js | v1.0
   Prefix: frac-

   Sections:
     1.  CSS Custom Properties (light / dark)
     2.  Fraction Display (.frac-display, .frac-num, .frac-bar, .frac-den)
     3.  Mixed Number (.frac-mixed, .frac-whole)
     4.  Circle Model (.frac-circle)
     5.  Bar / Rectangle Model (.frac-rect)
     6.  Number Line (.frac-numline)
     7.  Fraction Strip (.frac-strip, .frac-card)
     8.  Equivalence Chain (.frac-equiv-chain)
     9.  Fraction Input (.frac-input)
    10.  Comparison Layout (.frac-compare)
    11.  Type Chips (.frac-chip)
    12.  Visual Row / Column (.frac-visual-row, .frac-visual-col)
    13.  Dark Mode overrides
    14.  Responsive — 480px
    15.  Responsive — 360px
   ============================================================================= */


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

#game-root {
  --frac-shaded: #6366f1;
  --frac-shaded-light: #818cf8;
  --frac-empty: #e2e8f0;
  --frac-bar-color: #475569;
  --frac-text: #1e293b;
  --frac-text-muted: #64748b;
  --frac-bg-card: #ffffff;
  --frac-border: #cbd5e1;
  --frac-hl-bg: #eef2ff;
  --frac-hl-border: #6366f1;
  --frac-correct: #16a34a;
  --frac-correct-bg: #dcfce7;
  --frac-correct-border: #86efac;
  --frac-wrong: #dc2626;
  --frac-wrong-bg: #fee2e2;
  --frac-wrong-border: #fca5a5;
  --frac-nl-stroke: #475569;
  --frac-nl-text: #475569;
  --frac-input-bg: #f8fafc;
  --frac-input-border: #cbd5e1;
  --frac-input-focus: #6366f1;
}


/* =============================================================================
   2. FRACTION DISPLAY — stacked num / bar / den
   ============================================================================= */

.frac-display {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  vertical-align: middle;
  line-height: 1.1;
  font-weight: 700;
  color: var(--frac-text);
  user-select: none;
}

.frac-num,
.frac-den {
  display: block;
  text-align: center;
  padding: 1px 4px;
  min-width: 1.4em;
  transition: background 0.2s ease, color 0.2s ease;
  border-radius: 4px;
}

.frac-bar {
  display: block;
  width: 100%;
  min-width: 1.6em;
  height: 2px;
  background: var(--frac-bar-color);
  border-radius: 1px;
  margin: 1px 0;
}

/* ── Sizes ── */

.frac-sm { font-size: 14px; }
.frac-sm .frac-num,
.frac-sm .frac-den { padding: 0 3px; min-width: 1.2em; }
.frac-sm .frac-bar { min-width: 1.3em; height: 1.5px; }

.frac-md { font-size: 18px; }

.frac-lg { font-size: 26px; }
.frac-lg .frac-num,
.frac-lg .frac-den { padding: 2px 6px; min-width: 1.6em; }
.frac-lg .frac-bar { min-width: 2em; height: 3px; margin: 2px 0; }

/* ── Highlight states ── */

.frac-hl {
  background: var(--frac-hl-bg);
  color: var(--frac-hl-border);
  border-radius: 4px;
}


/* =============================================================================
   3. MIXED NUMBER — whole + stacked fraction inline
   ============================================================================= */

.frac-mixed {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  vertical-align: middle;
  font-weight: 700;
  color: var(--frac-text);
}

.frac-whole {
  font-size: 1.2em;
  line-height: 1;
  transition: background 0.2s ease, color 0.2s ease;
  padding: 2px 4px;
  border-radius: 4px;
}

.frac-mixed .frac-display {
  font-size: inherit;
}


/* =============================================================================
   4. CIRCLE MODEL (pie chart)
   ============================================================================= */

.frac-circle {
  display: inline-block;
  vertical-align: middle;
  line-height: 0;
}

.frac-circle svg {
  display: block;
}

.frac-circle path,
.frac-circle circle {
  transition: fill 0.25s ease;
}

.frac-circle path[data-sector]:hover {
  filter: brightness(1.1);
}

.frac-sector-label {
  pointer-events: none;
  user-select: none;
}


/* =============================================================================
   5. BAR / RECTANGLE MODEL
   ============================================================================= */

.frac-rect {
  display: inline-block;
  vertical-align: middle;
  line-height: 0;
}

.frac-rect svg {
  display: block;
}

.frac-rect rect {
  transition: fill 0.25s ease;
}

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


/* =============================================================================
   6. NUMBER LINE
   ============================================================================= */

.frac-numline {
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  padding: 4px 0;
}

.frac-numline svg {
  display: block;
  margin: 0 auto;
}

.frac-nl-tick-label {
  user-select: none;
  pointer-events: none;
}

/* Pulse animation for highlighted points */
@keyframes frac-nl-pulse {
  0%, 100% { r: 5; opacity: 1; }
  50% { r: 9; opacity: 0.7; }
}

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


/* =============================================================================
   7. FRACTION STRIP (row of clickable fraction cards)
   ============================================================================= */

.frac-strip {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  justify-content: center;
  padding: 8px 0;
}

.frac-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 10px 14px;
  border-radius: 12px;
  background: var(--frac-bg-card);
  border: 2px solid var(--frac-border);
  cursor: pointer;
  transition: all 0.2s ease;
  user-select: none;
  min-width: 64px;
}

.frac-card:hover {
  border-color: var(--frac-shaded-light);
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.15);
  transform: translateY(-1px);
}

.frac-card:active {
  transform: scale(0.97);
}

/* Card states */

.frac-card-selected {
  background: var(--frac-hl-bg);
  border-color: var(--frac-hl-border);
  box-shadow: 0 2px 10px rgba(99, 102, 241, 0.25);
}

.frac-card-correct {
  background: var(--frac-correct-bg);
  border-color: var(--frac-correct-border);
  box-shadow: 0 2px 10px rgba(22, 163, 74, 0.2);
}
.frac-card-correct .frac-num,
.frac-card-correct .frac-den {
  color: var(--frac-correct);
}
.frac-card-correct .frac-bar {
  background: var(--frac-correct);
}

.frac-card-wrong {
  background: var(--frac-wrong-bg);
  border-color: var(--frac-wrong-border);
  box-shadow: 0 2px 10px rgba(220, 38, 38, 0.2);
}
.frac-card-wrong .frac-num,
.frac-card-wrong .frac-den {
  color: var(--frac-wrong);
}
.frac-card-wrong .frac-bar {
  background: var(--frac-wrong);
}


/* =============================================================================
   8. EQUIVALENCE CHAIN — fractions linked with = signs and multipliers
   ============================================================================= */

.frac-equiv-chain {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  flex-wrap: wrap;
  padding: 12px 0;
}

.frac-equiv-arrow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
  padding: 0 4px;
}

.frac-equiv-eq {
  font-size: 22px;
  font-weight: 700;
  color: var(--frac-text-muted);
  line-height: 1;
}

.frac-equiv-mult {
  font-size: 11px;
  font-weight: 700;
  color: var(--frac-shaded);
  background: var(--frac-hl-bg);
  border: 1px solid var(--frac-hl-border);
  border-radius: 6px;
  padding: 1px 6px;
  white-space: nowrap;
}


/* =============================================================================
   9. FRACTION INPUT — editable stacked num/den text boxes
   ============================================================================= */

.frac-input {
  display: inline-flex;
  flex-direction: column;
  align-items: center;
  vertical-align: middle;
  gap: 0;
  position: relative;
}

.frac-input-num,
.frac-input-den {
  width: 46px;
  height: 34px;
  text-align: center;
  font-size: 18px;
  font-weight: 700;
  border: 2px solid var(--frac-input-border);
  background: var(--frac-input-bg);
  color: var(--frac-text);
  outline: none;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  -moz-appearance: textfield;
}

.frac-input-num::-webkit-outer-spin-button,
.frac-input-num::-webkit-inner-spin-button,
.frac-input-den::-webkit-outer-spin-button,
.frac-input-den::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.frac-input-num {
  border-radius: 8px 8px 0 0;
  border-bottom: none;
}

.frac-input-den {
  border-radius: 0 0 8px 8px;
  border-top: none;
}

.frac-input-bar {
  display: block;
  width: 46px;
  height: 3px;
  background: var(--frac-bar-color);
  flex-shrink: 0;
  position: relative;
  z-index: 1;
}

.frac-input-num:focus,
.frac-input-den:focus {
  border-color: var(--frac-input-focus);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.18);
  z-index: 2;
}

.frac-input-num[readonly],
.frac-input-den[readonly] {
  background: var(--frac-empty);
  color: var(--frac-text-muted);
  cursor: default;
}

/* Size variants */

.frac-input-sm .frac-input-num,
.frac-input-sm .frac-input-den {
  width: 36px;
  height: 28px;
  font-size: 14px;
}
.frac-input-sm .frac-input-bar {
  width: 36px;
  height: 2px;
}

.frac-input-lg .frac-input-num,
.frac-input-lg .frac-input-den {
  width: 56px;
  height: 40px;
  font-size: 22px;
}
.frac-input-lg .frac-input-bar {
  width: 56px;
  height: 4px;
}

/* Correct / wrong states */

.frac-input-correct .frac-input-num,
.frac-input-correct .frac-input-den {
  border-color: var(--frac-correct-border);
  background: var(--frac-correct-bg);
  color: var(--frac-correct);
}
.frac-input-correct .frac-input-bar {
  background: var(--frac-correct);
}

.frac-input-wrong .frac-input-num,
.frac-input-wrong .frac-input-den {
  border-color: var(--frac-wrong-border);
  background: var(--frac-wrong-bg);
  color: var(--frac-wrong);
}
.frac-input-wrong .frac-input-bar {
  background: var(--frac-wrong);
}


/* =============================================================================
   10. COMPARISON LAYOUT — fraction [op] fraction
   ============================================================================= */

.frac-compare {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 12px 0;
  flex-wrap: nowrap;
}

.frac-compare-left,
.frac-compare-right {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.frac-compare-op {
  font-size: 28px;
  font-weight: 800;
  color: var(--frac-text);
  min-width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 10px;
  background: var(--frac-empty);
  border: 2px solid var(--frac-border);
  transition: all 0.2s ease;
  user-select: none;
  flex-shrink: 0;
}

.frac-compare-op-unknown {
  color: var(--frac-text-muted);
  font-size: 24px;
}

.frac-compare-op-interactive {
  cursor: pointer;
}
.frac-compare-op-interactive:hover {
  border-color: var(--frac-shaded);
  background: var(--frac-hl-bg);
  box-shadow: 0 2px 8px rgba(99, 102, 241, 0.2);
}
.frac-compare-op-interactive:active {
  transform: scale(0.95);
}


/* =============================================================================
   11. TYPE CHIPS — colored pill labels for fraction types
   ============================================================================= */

.frac-chip {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 4px 12px;
  border-radius: 8px;
  font-weight: 700;
  font-size: 13px;
  margin: 2px 4px;
  transition: transform 0.15s ease;
  user-select: none;
  white-space: nowrap;
}

.frac-chip:hover {
  transform: scale(1.04);
}

.frac-chip-proper {
  background: #dcfce7;
  color: #16a34a;
  border: 1px solid #86efac;
}

.frac-chip-improper {
  background: #fee2e2;
  color: #dc2626;
  border: 1px solid #fca5a5;
}

.frac-chip-mixed {
  background: #fef3c7;
  color: #92400e;
  border: 1px solid #fcd34d;
}

.frac-chip-unit {
  background: #dbeafe;
  color: #1d4ed8;
  border: 1px solid #93c5fd;
}

.frac-chip-like {
  background: #d1fae5;
  color: #065f46;
  border: 1px solid #6ee7b7;
}

.frac-chip-unlike {
  background: #ede9fe;
  color: #6d28d9;
  border: 1px solid #c4b5fd;
}

.frac-chip-whole {
  background: #f1f5f9;
  color: #475569;
  border: 1px solid #cbd5e1;
}

.frac-chip-equivalent {
  background: #e0e7ff;
  color: #4338ca;
  border: 1px solid #a5b4fc;
}


/* =============================================================================
   12. VISUAL ROW / COLUMN — flex containers for multiple models
   ============================================================================= */

.frac-visual-row {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  flex-wrap: wrap;
  padding: 8px 0;
}

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

.frac-visual-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
  padding: 8px 0;
}


/* =============================================================================
   13. DARK MODE OVERRIDES
   ============================================================================= */

:root.dark #game-root,
.dark #game-root {
  --frac-shaded: #818cf8;
  --frac-shaded-light: #a5b4fc;
  --frac-empty: #334155;
  --frac-bar-color: #94a3b8;
  --frac-text: #e2e8f0;
  --frac-text-muted: #94a3b8;
  --frac-bg-card: #1e293b;
  --frac-border: #475569;
  --frac-hl-bg: #312e81;
  --frac-hl-border: #818cf8;
  --frac-correct: #4ade80;
  --frac-correct-bg: #052e16;
  --frac-correct-border: #22c55e;
  --frac-wrong: #f87171;
  --frac-wrong-bg: #450a0a;
  --frac-wrong-border: #ef4444;
  --frac-nl-stroke: #94a3b8;
  --frac-nl-text: #94a3b8;
  --frac-input-bg: #0f172a;
  --frac-input-border: #475569;
  --frac-input-focus: #818cf8;
}

/* ── Fraction display ── */

.dark .frac-hl {
  background: var(--frac-hl-bg);
  color: var(--frac-hl-border);
}

/* ── Circle & rect SVG strokes ── */

.dark .frac-circle path,
.dark .frac-circle circle {
  stroke: #64748b;
}

.dark .frac-rect line {
  stroke: #64748b;
}

.dark .frac-rect > svg > rect:first-child {
  stroke: #64748b;
}

/* ── Fraction strip cards ── */

.dark .frac-card {
  background: var(--frac-bg-card);
  border-color: var(--frac-border);
}

.dark .frac-card:hover {
  border-color: var(--frac-shaded-light);
  box-shadow: 0 2px 8px rgba(129, 140, 248, 0.2);
}

.dark .frac-card-selected {
  background: var(--frac-hl-bg);
  border-color: var(--frac-hl-border);
  box-shadow: 0 2px 10px rgba(129, 140, 248, 0.3);
}

.dark .frac-card-correct {
  background: var(--frac-correct-bg);
  border-color: var(--frac-correct-border);
}

.dark .frac-card-wrong {
  background: var(--frac-wrong-bg);
  border-color: var(--frac-wrong-border);
}

/* ── Equivalence chain ── */

.dark .frac-equiv-eq {
  color: var(--frac-text-muted);
}

.dark .frac-equiv-mult {
  color: var(--frac-shaded);
  background: var(--frac-hl-bg);
  border-color: var(--frac-hl-border);
}

/* ── Comparison operator ── */

.dark .frac-compare-op {
  background: var(--frac-empty);
  border-color: var(--frac-border);
  color: var(--frac-text);
}

.dark .frac-compare-op-unknown {
  color: var(--frac-text-muted);
}

.dark .frac-compare-op-interactive:hover {
  border-color: var(--frac-shaded);
  background: var(--frac-hl-bg);
  box-shadow: 0 2px 8px rgba(129, 140, 248, 0.25);
}

/* ── Type chips ── */

.dark .frac-chip-proper {
  background: #052e16;
  color: #4ade80;
  border-color: #22c55e;
}

.dark .frac-chip-improper {
  background: #450a0a;
  color: #fca5a5;
  border-color: #ef4444;
}

.dark .frac-chip-mixed {
  background: #451a03;
  color: #fcd34d;
  border-color: #f59e0b;
}

.dark .frac-chip-unit {
  background: #1e3a5f;
  color: #93c5fd;
  border-color: #3b82f6;
}

.dark .frac-chip-like {
  background: #022c22;
  color: #6ee7b7;
  border-color: #10b981;
}

.dark .frac-chip-unlike {
  background: #2e1065;
  color: #c4b5fd;
  border-color: #8b5cf6;
}

.dark .frac-chip-whole {
  background: #1e293b;
  color: #94a3b8;
  border-color: #475569;
}

.dark .frac-chip-equivalent {
  background: #312e81;
  color: #a5b4fc;
  border-color: #6366f1;
}

/* ── Number line dark-mode text ── */

.dark .frac-nl-tick-label {
  fill: var(--frac-nl-text);
}


/* =============================================================================
   14. RESPONSIVE — max-width 480px
   ============================================================================= */

@media (max-width: 480px) {

  /* Fraction display sizes shrink */
  .frac-md {
    font-size: 16px;
  }

  .frac-lg {
    font-size: 22px;
  }
  .frac-lg .frac-num,
  .frac-lg .frac-den {
    padding: 1px 4px;
  }

  /* Circle model — cap size */
  .frac-circle svg {
    max-width: 100px;
    max-height: 100px;
  }

  /* Bar model — fit screen */
  .frac-rect svg {
    max-width: 100%;
    height: auto;
  }

  /* Number line — allow horizontal scroll */
  .frac-numline {
    overflow-x: auto;
  }

  /* Strip cards — smaller */
  .frac-strip {
    gap: 6px;
  }

  .frac-card {
    padding: 8px 10px;
    min-width: 54px;
    border-radius: 10px;
  }

  /* Equivalence chain */
  .frac-equiv-chain {
    gap: 4px;
  }

  .frac-equiv-eq {
    font-size: 18px;
  }

  /* Fraction input */
  .frac-input-num,
  .frac-input-den {
    width: 40px;
    height: 30px;
    font-size: 16px;
  }

  .frac-input-bar {
    width: 40px;
  }

  /* Comparison */
  .frac-compare {
    gap: 8px;
  }

  .frac-compare-op {
    font-size: 24px;
    min-width: 38px;
    height: 38px;
  }

  /* Type chips */
  .frac-chip {
    font-size: 12px;
    padding: 3px 10px;
  }

  /* Visual row */
  .frac-visual-row {
    gap: 6px;
  }
}


/* =============================================================================
   15. RESPONSIVE — max-width 360px (very small phones)
   ============================================================================= */

@media (max-width: 360px) {

  .frac-md {
    font-size: 14px;
  }

  .frac-lg {
    font-size: 18px;
  }

  .frac-circle svg {
    max-width: 80px;
    max-height: 80px;
  }

  .frac-strip {
    gap: 4px;
  }

  .frac-card {
    padding: 6px 8px;
    min-width: 46px;
    border-radius: 8px;
  }

  .frac-card .frac-display {
    font-size: 13px;
  }

  .frac-equiv-chain {
    gap: 3px;
  }

  .frac-equiv-eq {
    font-size: 16px;
  }

  .frac-equiv-mult {
    font-size: 10px;
    padding: 0 4px;
  }

  .frac-input-num,
  .frac-input-den {
    width: 34px;
    height: 26px;
    font-size: 14px;
  }

  .frac-input-bar {
    width: 34px;
    height: 2px;
  }

  .frac-compare {
    gap: 6px;
  }

  .frac-compare-op {
    font-size: 20px;
    min-width: 32px;
    height: 32px;
    border-radius: 8px;
  }

  .frac-chip {
    font-size: 11px;
    padding: 2px 8px;
    border-radius: 6px;
  }

  .frac-visual-row {
    gap: 4px;
  }

  .frac-mixed {
    gap: 2px;
  }

  .frac-whole {
    font-size: 1em;
    padding: 1px 2px;
  }
}