/* ==========================================================================
   Module: Numbers & Characters (AQA 8525 §3.3.1 & §3.3.2)
   Imports Shared Design System
   ========================================================================== */
@import url('../../shared/styles.css');

/* Layout Container */
.module-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg-surface);
  border-bottom: 1px solid var(--border-color);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.module-header-inner {
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 20px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.nav-back-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 12px;
  font-weight: 600;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.nav-back-link:hover {
  background: var(--border-color);
  color: var(--text-primary);
}

.view-tabs {
  display: flex;
  align-items: center;
  gap: 4px;
  background: var(--bg-surface-elevated);
  padding: 4px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
}

.view-tab-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  border-radius: var(--radius-sm);
  border: none;
  background: transparent;
  color: var(--text-secondary);
  font-size: 12.5px;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.view-tab-btn:hover {
  color: var(--text-primary);
}

.view-tab-btn.active {
  background: var(--accent-primary);
  color: #ffffff;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.15);
}

.tab-view {
  display: none;
}

.tab-view.active {
  display: block;
}

.module-container {
  max-width: 1400px;
  margin: 0 auto;
  padding: 24px 20px 48px;
}

/* Banner */
.view-banner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px 20px;
  margin-bottom: 20px;
  flex-wrap: wrap;
}

.banner-left {
  display: flex;
  align-items: center;
  gap: 14px;
}

.banner-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, #4f46e5 0%, #3b82f6 100%);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #ffffff;
  box-shadow: 0 4px 12px rgba(79, 70, 229, 0.25);
}

.banner-title {
  margin: 0 0 2px 0;
  font-size: 17px;
  font-weight: 800;
  color: var(--text-primary);
}

.banner-desc {
  margin: 0;
  font-size: 13px;
  color: var(--text-secondary);
}

/* Bit Register Visualizer */
.register-container {
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 24px;
  margin-bottom: 24px;
  box-shadow: var(--shadow-sm);
}

.nibbles-wrapper {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin-bottom: 20px;
}

@media (max-width: 768px) {
  .nibbles-wrapper {
    grid-template-columns: 1fr;
  }
}

.nibble-box {
  background: var(--bg-surface-elevated);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 16px;
  position: relative;
  transition: border-color var(--transition-fast);
}

.nibble-box.nibble-high {
  border-color: rgba(99, 102, 241, 0.4);
}

.nibble-box.nibble-low {
  border-color: rgba(16, 185, 129, 0.4);
}

.nibble-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 12px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.nibble-title {
  font-size: 12px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

.nibble-hex-badge {
  font-family: var(--font-mono);
  font-size: 14px;
  font-weight: 800;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
}

.nibble-bits-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 8px;
}

.bit-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: var(--bg-surface);
  border: 2px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px 6px;
  cursor: pointer;
  user-select: none;
  transition: all var(--transition-fast);
  position: relative;
}

.bit-card:hover {
  transform: translateY(-2px);
  border-color: var(--accent-primary);
}

.bit-place-value {
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 700;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.bit-place-value.msb-negative {
  color: #ef4444;
}

.bit-state-bulb {
  width: 44px;
  height: 48px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 26px;
  font-weight: 900;
  color: var(--text-muted);
  transition: all var(--transition-fast);
}

.bit-card.active .bit-state-bulb {
  background: var(--accent-primary);
  border-color: var(--accent-primary);
  color: #ffffff;
  box-shadow: 0 0 16px rgba(79, 70, 229, 0.45);
}

.bit-card.active.msb-card .bit-state-bulb {
  background: #dc2626;
  border-color: #dc2626;
  box-shadow: 0 0 16px rgba(220, 38, 38, 0.45);
}

.bit-card.active .bit-place-value {
  color: var(--accent-primary);
}

.bit-card.active.msb-card .bit-place-value {
  color: #ef4444;
}

/* Register Summary Bar */
.register-summary-bar {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 14px;
  padding-top: 18px;
  border-top: 1px solid var(--border-color);
}

.summary-card {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 12px 16px;
}

.summary-label {
  font-size: 11px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-bottom: 4px;
}

.summary-value {
  font-family: var(--font-mono);
  font-size: 22px;
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: baseline;
  gap: 6px;
}

.summary-subtext {
  font-size: 11px;
  font-family: sans-serif;
  color: var(--text-secondary);
  font-weight: 500;
}

/* Interactive Binary Addition Grid */
.addition-table-container {
  overflow-x: auto;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 20px;
  margin-bottom: 20px;
}

.addition-grid {
  display: inline-grid;
  grid-template-columns: 80px repeat(8, 52px) 80px;
  gap: 6px;
  align-items: center;
  font-family: var(--font-mono);
  text-align: center;
}

.grid-cell {
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  font-size: 16px;
  font-weight: 700;
}

.row-label {
  text-align: left;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-secondary);
}

.carry-cell {
  background: rgba(234, 179, 8, 0.12);
  border: 1px dashed rgba(234, 179, 8, 0.4);
  color: #ca8a04;
  font-size: 13px;
  height: 32px;
}

.carry-cell.has-carry {
  background: #ca8a04;
  color: #ffffff;
  border-style: solid;
}

.digit-input-cell {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  cursor: pointer;
  user-select: none;
  transition: all var(--transition-fast);
}

.digit-input-cell:hover {
  border-color: var(--accent-primary);
  transform: scale(1.05);
}

.digit-input-cell.one {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}

.sum-line {
  grid-column: 1 / -1;
  height: 2px;
  background: var(--text-primary);
  margin: 4px 0;
}

.sum-cell {
  background: var(--bg-surface-elevated);
  border: 2px solid var(--accent-primary);
  font-size: 18px;
  font-weight: 900;
  color: var(--accent-primary);
}

.overflow-indicator {
  padding: 14px 18px;
  border-radius: var(--radius-md);
  margin-top: 14px;
  display: none;
  font-size: 13px;
  line-height: 1.5;
}

.overflow-indicator.visible {
  display: block;
  background: rgba(239, 68, 68, 0.12);
  border: 1px solid rgba(239, 68, 68, 0.35);
  color: #ef4444;
}

/* Binary Shift Simulator */
.shift-controls {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
  margin: 16px 0;
}

/* Data Units Comparison Ladder */
.units-ladder {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}

.unit-step {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px 20px;
  transition: transform var(--transition-fast);
}

.unit-step:hover {
  transform: translateX(4px);
  border-color: var(--accent-primary);
}

/* Character Encoding Grid */
.char-token-stream {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  padding: 16px;
  background: var(--bg-surface-elevated);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  min-height: 100px;
}

.char-token {
  display: flex;
  flex-direction: column;
  align-items: center;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 8px 12px;
  font-family: var(--font-mono);
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.char-token .char-symbol {
  font-size: 20px;
  font-weight: 800;
  color: var(--text-primary);
  margin-bottom: 4px;
}

.char-token .char-denary {
  font-size: 11px;
  color: var(--text-secondary);
}

.char-token .char-hex {
  font-size: 11px;
  color: #3b82f6;
  font-weight: 700;
}

.char-token .char-bin {
  font-size: 10px;
  color: #10b981;
  font-weight: 600;
}

/* 3-Way Synchronized Number Converter */
.converter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 14px;
}

.converter-input-card {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  transition: border-color var(--transition-fast);
}

.converter-input-card:focus-within {
  border-color: var(--accent-primary);
  box-shadow: 0 0 0 2px rgba(79, 70, 229, 0.15);
}

.converter-card-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-secondary);
}

.base-badge {
  font-size: 10px;
  font-weight: 800;
  padding: 2px 7px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
}

.converter-input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
  width: 100%;
}

.converter-input {
  width: 100%;
  background: var(--bg-surface);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  padding: 10px 42px 10px 14px;
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 800;
  color: var(--text-primary);
  outline: none;
  transition: border-color var(--transition-fast);
}

.converter-input:focus {
  border-color: var(--accent-primary);
}

/* Remove native spin buttons for seamless uniform steppers across all 3 inputs */
.converter-input[type="number"]::-webkit-outer-spin-button,
.converter-input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}
.converter-input[type="number"] {
  -moz-appearance: textfield;
  appearance: textfield;
}

.converter-steppers {
  position: absolute;
  right: 6px;
  top: 50%;
  transform: translateY(-50%);
  display: flex;
  flex-direction: column;
  gap: 2px;
  z-index: 2;
}

.converter-step-arrow {
  width: 26px;
  height: 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: 3px;
  color: var(--text-secondary);
  font-size: 9px;
  line-height: 1;
  cursor: pointer;
  padding: 0;
  transition: all var(--transition-fast);
  user-select: none;
}

.converter-step-arrow:hover {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}

.converter-step-arrow:active {
  transform: scale(0.92);
}

/* Full Binary Stream Box in Tab 4 */
.full-binary-box {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  font-family: var(--font-mono);
  font-size: 14.5px;
  font-weight: 700;
  color: #10b981;
  letter-spacing: 1.5px;
  line-height: 1.7;
  word-break: break-all;
  white-space: pre-wrap;
  min-height: 52px;
  user-select: all;
}

/* Target Practice Animation */
.target-card-matched {
  animation: pulseMatch 0.5s ease;
  border-color: #10b981 !important;
  background: rgba(16, 185, 129, 0.08) !important;
}

@keyframes pulseMatch {
  0% { transform: scale(1); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0.7); }
  50% { transform: scale(1.02); box-shadow: 0 0 20px 4px rgba(16, 185, 129, 0.25); }
  100% { transform: scale(1); box-shadow: 0 0 0 0 rgba(16, 185, 129, 0); }
}

/* Color Presets */
.color-preset-btn {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 11.5px;
  padding: 4px 10px;
}

/* Stepper buttons */
.stepper-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 13px;
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.stepper-btn:hover {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  transform: translateY(-1px);
}

.stepper-btn:active {
  transform: translateY(1px);
}

/* Maths Operations Selector */
.maths-mode-selector {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 20px;
}

.maths-mode-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-secondary);
  font-size: 13px;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.maths-mode-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

.maths-mode-btn.active {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}

.maths-section {
  display: none;
}

.maths-section.active {
  display: block;
}

/* Subtraction Walkthrough Cards */
.sub-step-card {
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: 14px 18px;
  margin-bottom: 12px;
}

.sub-step-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}

.sub-step-title {
  font-size: 13px;
  font-weight: 800;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.sub-step-bits {
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 800;
  letter-spacing: 2px;
  color: var(--text-primary);
  background: var(--bg-surface);
  padding: 6px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  display: inline-block;
}

/* Bitwise Logic Workbench */
.logic-op-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-bottom: 16px;
}

.logic-op-btn {
  padding: 8px 18px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-color);
  background: var(--bg-surface);
  color: var(--text-secondary);
  font-family: var(--font-mono);
  font-size: 13px;
  font-weight: 800;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.logic-op-btn:hover {
  border-color: var(--accent-primary);
  color: var(--text-primary);
}

.logic-op-btn.active {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.15);
}

.preset-pill-btn {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  font-size: 11.5px;
  font-weight: 600;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.preset-pill-btn:hover {
  background: var(--border-color);
  color: var(--text-primary);
}

/* ==========================================================================
   Huffman Coding Lab Styles
   ========================================================================== */
.huffman-workspace-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

@media (min-width: 1024px) {
  .huffman-workspace-grid {
    grid-template-columns: 1fr 1fr;
  }
}

.huffman-preset-btn.active {
  background: var(--accent-primary);
  color: #ffffff;
  border-color: var(--accent-primary);
}

.huffman-freq-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: var(--radius-sm);
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  font-family: var(--font-mono);
  font-size: 12px;
  cursor: pointer;
  transition: all var(--transition-fast);
}

.huffman-freq-badge:hover,
.huffman-freq-badge.active {
  border-color: #f59e0b;
  background: rgba(245, 158, 11, 0.15);
  color: #f59e0b;
}

.huffman-freq-badge .char-pill {
  font-weight: 800;
  color: var(--accent-soft-text);
}

.huffman-freq-badge .count-pill {
  font-size: 10.5px;
  padding: 1px 5px;
  border-radius: 3px;
  background: var(--bg-root);
  color: var(--text-muted);
}

.huffman-svg-node {
  cursor: pointer;
  transition: all 0.2s ease;
}

.huffman-svg-node text {
  user-select: none;
}

.huffman-svg-node:hover circle,
.huffman-svg-node.highlighted circle {
  stroke: #f59e0b !important;
  stroke-width: 3px !important;
  filter: drop-shadow(0 0 6px rgba(245, 158, 11, 0.6));
}

.huffman-edge {
  transition: stroke 0.2s ease, stroke-width 0.2s ease;
}

.huffman-edge.highlighted {
  stroke: #f59e0b !important;
  stroke-width: 3.5px !important;
}

.huffman-edge-label.highlighted {
  fill: #f59e0b !important;
  font-weight: 900 !important;
}

.huffman-row {
  cursor: pointer;
  transition: background-color 0.2s ease;
}

.huffman-row:hover,
.huffman-row.active-huffman-row {
  background: rgba(245, 158, 11, 0.12) !important;
}

.huffman-bit-token {
  display: inline-block;
  padding: 1px 4px;
  margin: 1px 2px;
  border-radius: 3px;
  background: var(--bg-surface-elevated);
  border: 1px solid var(--border-color);
  font-weight: 700;
  letter-spacing: 0.5px;
  transition: all 0.15s ease;
  cursor: default;
}

.huffman-bit-token:hover,
.huffman-bit-token.active-token {
  background: #38bdf8;
  color: #0f172a;
  border-color: #38bdf8;
  transform: scale(1.08);
}