:root {
  --bg: #f6f7fb;
  --bg-muted: #e9ebf3;
  --text: #1f2630;
  --primary: #4a6cf7;
  --border: #cfd5e4;
  --accent: #f0f4ff;
  --surface: #ffffff;
  --muted: #6b7280;

  /* Vaporwave Palette */
  --vw-orange: #FF5E00;
  --vw-fuchsia: #FF00FF;
  --vw-blue: #00FFFF;
  --vw-purple: #8A2BE2;
  --vw-green: #39FF14;
  --vw-red: #FF2D55;
}

body.dark {
  --bg: #111827;
  --bg-muted: #1f2937;
  --text: #ffffff;
  --primary: #8b9cf9;
  --border: #374151;
  --accent: #1f2937;
  --surface: #0b1221;
}

.header-left {
  display: flex;
  align-items: center;
  gap: 1.5rem;
}

.back-link {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: var(--muted);
  font-weight: 600;
  font-size: 0.875rem;
  transition: color 0.2s;
}

.back-link:hover {
  color: var(--primary);
}

.header-actions {
  display: flex;
  flex-direction: row;
  gap: 0.5rem;
  align-items: center;
}

.mode-selector {
  display: flex;
  gap: 0.5rem;
  padding: 0.75rem 1rem 0;
}

.mode-btn {
  background-color: var(--bg);
  border: 1px solid var(--border);
  padding: 0.5rem 1.25rem;
  border-radius: 0.5rem;
  cursor: pointer;
  font-weight: 700;
  color: var(--text);
  font-size: 0.9rem;
  transition: all 0.2s;
}

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

.mode-btn.active {
  background-color: var(--primary);
  color: white;
  border-color: var(--primary);
}

.game-selector {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.game-selector label {
  font-weight: 600;
  color: var(--muted);
  font-size: 0.875rem;
}

.game-btn {
  background-color: var(--bg);
  border: 1px solid var(--border);
  padding: 0.4rem 0.875rem;
  border-radius: 0.5rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
  font-size: 0.85rem;
  transition: all 0.2s;
}

.game-btn:hover {
  border-color: var(--vw-purple);
}

.game-btn.active {
  background-color: var(--vw-purple);
  color: white;
  border-color: var(--vw-purple);
}

.game-stats {
  display: flex;
  gap: 1rem;
  font-weight: 700;
  font-size: 0.9rem;
  color: var(--vw-orange);
}

.toolbar {
  background-color: var(--surface);
  border-bottom: 1px solid var(--border);
  padding: 0.75rem 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.75rem;
  position: sticky;
  top: 0;
  z-index: 10;
}

.varcount-selector {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.varcount-selector label {
  font-weight: 600;
  color: var(--muted);
  font-size: 0.875rem;
}

.varcount-btn,
.secondary-btn {
  background-color: var(--bg);
  border: 1px solid var(--border);
  padding: 0.4rem 0.875rem;
  border-radius: 0.5rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
  font-size: 0.875rem;
  transition: all 0.2s;
}

.varcount-btn:hover,
.secondary-btn:hover {
  border-color: var(--primary);
}

.varcount-btn.active {
  background-color: var(--primary);
  color: white;
  border-color: var(--primary);
}

.secondary-btn.active {
  background-color: var(--vw-purple);
  color: white;
  border-color: var(--vw-purple);
}

.secondary-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.secondary-btn:disabled:hover {
  border-color: var(--border);
}

.type-selector {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.type-selector label {
  font-weight: 600;
  color: var(--muted);
  font-size: 0.875rem;
}

.type-btn {
  background-color: var(--bg);
  border: 1px solid var(--border);
  padding: 0.4rem 0.875rem;
  border-radius: 0.5rem;
  cursor: pointer;
  font-weight: 600;
  color: var(--text);
  font-size: 0.875rem;
  transition: all 0.2s;
}

.type-btn:hover {
  border-color: var(--primary);
}

.type-btn.active {
  background-color: var(--primary);
  color: white;
  border-color: var(--primary);
}

.toolbar-options {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
}

.gray-order-toggle {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--muted);
  cursor: pointer;
}

.gray-order-toggle input[type="checkbox"] {
  width: 16px;
  height: 16px;
  accent-color: var(--primary);
  cursor: pointer;
}

.instructional-container {
  padding: 1rem 0 0;
}

.speech-bubble {
  background-color: var(--accent);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 0.85rem 1.1rem;
  font-size: 0.9rem;
  color: var(--text);
  position: relative;
}

.bubble-grid {
  display: grid;
  grid-template-rows: 1fr;
  transition: grid-template-rows 0.25s ease;
}

.bubble-grid.collapsed {
  grid-template-rows: 0fr;
}

.bubble-grid-inner {
  overflow: hidden;
  min-height: 90px;
}

.speech-bubble p {
  margin: 0;
  padding-right: 1.5rem;
}

.speech-bubble-close {
  position: absolute;
  top: 0.5rem;
  right: 0.6rem;
  width: 1.5rem;
  height: 1.5rem;
  border: none;
  border-radius: 50%;
  background: transparent;
  color: var(--text);
  font-size: 1.2rem;
  line-height: 1;
  cursor: pointer;
}

.speech-bubble-close:hover {
  background-color: var(--border);
}

#tutorialContinueBtn {
  margin-top: 0.75rem;
}

.tutorial-expr-orange {
  color: var(--vw-orange);
  font-weight: 600;
}

.tutorial-expr-cyan {
  color: var(--vw-blue);
  font-weight: 600;
}

.workspace {
  display: flex;
  flex-direction: row;
  flex-wrap: wrap;
  padding: 1rem 0 2rem;
  gap: 1rem;
  align-items: stretch;
  background-color: var(--bg);
  min-height: 400px;
}

.panel {
  flex: 1;
  min-width: 280px;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1rem;
  display: flex;
  flex-direction: column;
  box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
  overflow: auto;
}

.panel h3 {
  margin: 0 0 0.75rem;
}

.kmap-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.kmap-panel-header h3 {
  margin: 0;
}

.group-helper-note {
  color: var(--vw-purple);
  font-size: 0.8rem;
  font-weight: 700;
  margin: -0.25rem 0 0.75rem;
}

.kmap-below-grid-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
  flex-wrap: wrap;
  margin: 0.75rem 0;
}

.truth-table-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  flex-wrap: wrap;
  margin-bottom: 0.5rem;
}

.truth-table-header h3 {
  margin: 0;
}

.tutorial-step {
  margin-top: 1.5rem;
  background-color: var(--bg);
  padding: 1rem;
  border-radius: 0.5rem;
  font-size: 0.875rem;
  line-height: 1.6;
}

/* Truth table */
.truth-table {
  border-collapse: collapse;
  width: 100%;
}

.truth-table th,
.truth-table td {
  border: 1px solid var(--border);
  text-align: center;
  padding: 0.45rem 0.6rem;
}

.truth-table th {
  background-color: var(--bg-muted);
  border: 2px solid var(--border);
  font-weight: 700;
}

.truth-table td.value-cell {
  cursor: pointer;
  font-weight: 700;
  user-select: none;
  transition: background-color 0.15s, color 0.15s;
}

.truth-table td.value-cell:hover {
  background-color: var(--accent);
}

.truth-table tr.is-active {
  background-color: rgba(74, 108, 247, 0.12);
}

.truth-table tr.is-active td.value-cell {
  outline: 2px solid var(--primary);
  outline-offset: -2px;
}

.adjacency-note {
  color: var(--vw-orange);
  font-size: 0.8rem;
  font-weight: 700;
  margin: -0.25rem 0 0.75rem;
}

.truth-table tr.circle-highlight {
  background-color: var(--circle-bg, transparent);
  outline: 2px solid var(--circle-color, var(--primary));
  outline-offset: -2px;
}

.truth-table tr.row-adjacent {
  background-color: var(--adjacency-bg, rgba(255, 94, 0, 0.14));
  outline: 2px dashed var(--adjacency-color, var(--vw-orange));
  outline-offset: -2px;
}

.truth-table td.bit-diff {
  color: var(--bit-diff-color, var(--vw-orange));
  font-weight: 800;
}

.truth-table tr.just-changed {
  animation: kmap-row-flash 0.5s ease;
}

@keyframes kmap-row-flash {
  from { background-color: rgba(255, 94, 0, 0.35); }
  to { background-color: transparent; }
}

/* K-map grid (ported layout, from FiniteStateMachine) */
.kmap-grid-collection {
  display: grid;
  gap: 1rem;
}

.kmap-grid-wrapper {
  position: relative;
}

.kmap-submap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.5rem;
}

.kmap-submap-label {
  font-weight: 700;
  text-align: center;
  margin-bottom: 0.25rem;
}

.kmap-table {
  border-collapse: collapse;
  width: 100%;
}

.kmap-table th,
.kmap-table td {
  border: 1px solid var(--border);
  text-align: center;
  padding: 0.3rem;
  transition: background-color 0.3s ease;
}

.kmap-table th {
  background-color: var(--bg-muted);
  border: 2px solid var(--border);
}

.kmap-table input {
  width: 40px;
  text-align: center;
  padding: 0.3rem;
  cursor: pointer;
  font-weight: 700;
  border: none;
  background: transparent;
  color: var(--text);
  caret-color: transparent;
}

/* Group Helper repurposes clicks to commit a group instead of toggling the
   cell's value, so the normal focus ring (implying "click to edit") is
   suppressed while it's active. */
body.group-helper-active .kmap-table input:focus {
  outline: none;
}

.kmap-table td.is-active {
  background-color: rgba(74, 108, 247, 0.18);
  outline: 2px solid var(--primary);
  outline-offset: -2px;
}

.kmap-table td.adjacency-highlight {
  background-color: var(--adjacency-cell-bg, rgba(255, 94, 0, 0.18));
  outline: 2px dashed var(--adjacency-cell-color, var(--vw-orange));
  outline-offset: -2px;
}

.kmap-table td.group-preview {
  background-color: rgba(138, 43, 226, 0.2);
  outline: 2px dashed var(--vw-purple);
  outline-offset: -2px;
}

.kmap-table td.just-changed {
  animation: kmap-row-flash 0.5s ease;
}

.kmap-corner-label {
  position: relative;
  min-width: 56px;
  min-height: 40px;
  display: grid;
  place-items: center;
  color: var(--text);
  font-weight: 700;
}

.kmap-corner-label .kmap-diagonal {
  position: absolute;
  inset: 0.35rem;
  background: none;
}

.kmap-corner-label .kmap-diagonal::before {
  content: "";
  position: absolute;
  top: -20px;
  left: 51%;
  bottom: -20px;
  border-left: 1px solid var(--border);
  transform: rotate(-45deg);
  transform-origin: center;
}

.kmap-corner-label .kmap-variable-block {
  position: relative;
  z-index: 1;
  display: flex;
  gap: 0.2rem;
  font-size: 0.85rem;
}

.kmap-corner-label .kmap-vars-row {
  align-self: flex-start;
  transform: translateY(20px) translateX(-10px);
}

.kmap-corner-label .kmap-vars-col {
  align-self: flex-end;
  transform: translateY(-15px) translateX(20px);
}

.kmap-var-top {
  transform: translateY(-3px);
}

.kmap-var-bottom {
  transform: translateY(10px);
}

.kmap-gray-code {
  display: inline-block;
  font-weight: 700;
}

.kmap-gray-row {
  transform: translateX(-10px);
}

.kmap-gray-col {
  transform: translateY(-5px);
}

/* Circle-grouping SVG overlay (ported from FiniteStateMachine) */
.kmap-circle-overlay {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 2;
}

.kmap-circle-overlay.hidden {
  display: none;
}

.kmap-circle-overlay svg {
  width: 100%;
  height: 100%;
  overflow: visible;
}

.kmap-circle-section {
  opacity: 1;
  transition: opacity 1.5s ease;
}

.kmap-circle-section.kmap-circle-fade-out,
.kmap-circle-section.kmap-circle-fade-in {
  opacity: 0;
}

.kmap-circle-rect {
  stroke-linejoin: round;
}

.kmap-circle-link {
  stroke-linecap: round;
}

/* Variable tray + expression tray (ported from FiniteStateMachine) */
.kmap-variable-tray {
  display: flex;
  gap: 0.5rem;
  align-items: center;
  flex-wrap: wrap;
  margin-bottom: 0.5rem;
}

.kmap-tray-label {
  font-weight: 600;
}

.kmap-variable-items {
  display: flex;
  gap: 0.35rem;
  flex-wrap: wrap;
}

.kmap-token {
  border: 1px solid var(--border);
  background: var(--primary);
  color: #fff;
  border-radius: 8px;
  padding: 0.2rem 0.5rem;
  cursor: grab;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.08);
}

.kmap-token-operator {
  background: var(--primary);
  color: #fff;
}

.kmap-expression-tray-wrapper {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
  align-items: stretch;
}

.kmap-expression-tray {
  width: 100%;
  min-width: 280px;
  min-height: 44px;
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.4rem 0.6rem;
  display: flex;
  align-items: flex-start;
  gap: 0.35rem;
  flex-wrap: wrap;
  cursor: text;
  background: var(--surface);
}

.kmap-expression-tray:focus {
  outline: 2px solid var(--accent);
}

.kmap-f-tray-block {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  padding-top: 0.35rem;
  border-top: 1px dashed var(--border);
}

.kmap-f-label-row {
  display: flex;
  align-items: baseline;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.kmap-tray-hint {
  color: var(--muted);
  font-size: 0.85rem;
  font-style: italic;
}

.kmap-overline-text {
  position: relative;
}

.kmap-overline-text::before {
  content: '';
  position: absolute;
  left: 1px;
  right: 1px;
  top: -1px;
  border-top: 2px solid currentColor;
}

.kmap-expr-placeholder {
  color: var(--muted);
  font-size: 0.95rem;
}

.kmap-expr-token {
  border: none;
  border-radius: 8px;
  padding: 0;
  background: var(--surface);
  cursor: grab;
  box-shadow: none;
  display: inline-flex;
  align-items: center;
  min-height: 32px;
  justify-content: center;
}

.kmap-expr-token.selected {
  border: 2px solid var(--vw-orange);
}

.kmap-expr-token.operator {
  background: transparent;
  color: var(--text);
}

.kmap-expr-token-inner {
  position: relative;
  line-height: 1.05;
}

.kmap-expr-token-inner.negated::before {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  top: -4px;
  border-top: 2px solid currentColor;
}

.kmap-expression-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  justify-content: flex-end;
  width: 100%;
}

.kmap-expression-actions button {
  background-color: var(--primary);
  color: #fff;
  border: none;
  padding: 0.5rem 1.25rem;
  border-radius: 0.5rem;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
  transition: filter 0.15s, background-color 0.15s;
}

.kmap-expression-actions button:hover {
  filter: brightness(1.1);
}

.kmap-drop-marker {
  width: 2px;
  height: 24px;
  background: var(--text);
  opacity: 0.75;
  box-shadow: 0 0 0 1px var(--border);
  align-self: stretch;
}

.kmap-expression {
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 0.6rem;
  margin-top: 0.75rem;
}

.expression-directions {
  color: var(--muted);
  font-size: 0.8rem;
  margin: 0;
}

.kmap-expression-label {
  font-weight: 700;
  display: inline-block;
}

.kmap-expression button.verified {
  background: var(--vw-green);
  color: #000;
}

.kmap-expression button.not-minimal {
  outline: 2px dashed var(--vw-orange);
  outline-offset: 2px;
}

.kmap-expression button.failed {
  background: var(--vw-red);
  color: #fff;
}

.verify-result {
  font-size: 0.875rem;
  min-height: 1.2rem;
}

.verify-result.passed {
  color: #16a34a;
}

.verify-result.failed {
  color: var(--vw-red);
}

/* Practice mode / games */
.game-feedback {
  font-weight: 700;
  font-size: 0.95rem;
  min-height: 1.4rem;
  margin: 0.5rem 0;
}

.game-feedback.correct {
  color: #16a34a;
}

.game-feedback.incorrect {
  color: var(--vw-red);
}

.game-answer-actions {
  display: flex;
  gap: 0.75rem;
  margin-top: 0.75rem;
  flex-wrap: wrap;
}

.game-answer-actions button {
  background-color: var(--primary);
  color: #fff;
  border: none;
  padding: 0.5rem 1.25rem;
  border-radius: 0.5rem;
  font-weight: 600;
  cursor: pointer;
  transition: filter 0.15s;
}

.game-answer-actions button:hover {
  filter: brightness(1.1);
}

.game-answer-actions button:disabled {
  opacity: 0.5;
  cursor: default;
}

.kmap-table td.game-claimed {
  background-color: rgba(255, 0, 255, 0.18);
  outline: 2px solid var(--vw-fuchsia);
  outline-offset: -2px;
}

.kmap-table td.game-selected {
  background-color: rgba(0, 255, 255, 0.2);
  outline: 2px solid var(--vw-blue);
  outline-offset: -2px;
}

.game-round-meta {
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 0.5rem;
}

/* 1-cells (SOP) / 0-cells (POS) tinted to show which value the primary tray is circling */
.kmap-table td.target-value {
  background-color: rgba(74, 108, 247, 0.08);
}

.subscript-text {
  vertical-align: sub;
  font-size: 0.82em;
}

.superscript-text {
  vertical-align: super;
  font-size: 0.82em;
}

/* Dialogs */
.dialog-backdrop.hidden {
  display: none;
}

.form-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
}

/* Switch UI */
.switch {
  position: relative;
  display: inline-block;
  width: 50px;
  height: 24px;
}

.switch input {
  opacity: 0;
  width: 0;
  height: 0;
}

.slider {
  position: absolute;
  cursor: pointer;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: var(--bg-muted);
  transition: .4s;
  border: 1px solid var(--border);
}

.slider:before {
  position: absolute;
  content: "";
  height: 16px;
  width: 16px;
  left: 4px;
  bottom: 3px;
  background-color: white;
  transition: .4s;
}

input:checked + .slider {
  background-color: var(--primary);
}

input:checked + .slider:before {
  transform: translateX(26px);
}

.slider.round {
  border-radius: 24px;
}

.slider.round:before {
  border-radius: 50%;
}