@font-face {
  font-family: "Inter";
  src: url("../fonts/Inter-Variable.ttf") format("truetype");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Inter";
  src: url("../fonts/Inter-Italic-Variable.ttf") format("truetype");
  font-weight: 100 900;
  font-style: italic;
  font-display: swap;
}

:root {
  --bg: #eef2f7;
  --surface: #ffffff;
  --surface-soft: #f7f9fc;
  --ink: #172033;
  --muted: #64748b;
  --line: #d7deea;
  --line-strong: #172033;
  --accent: #2563eb;
  --accent-strong: #1d4ed8;
  --accent-soft: #dbeafe;
  --given-bg: #f6f7ff;
  --given-ink: #1e1b4b;
  --assist-line: rgba(37, 99, 235, 0.2);
  --value-line: rgba(251, 191, 36, 0.22);
  --value-line-strong: rgba(146, 64, 14, 0.34);
  --value-match: var(--bad-ink);
  --good: #dcfce7;
  --good-ink: #166534;
  --warn: #fef3c7;
  --warn-ink: #92400e;
  --bad: #fee2e2;
  --bad-ink: #991b1b;
  --remove: #fecaca;
  --remove-border: #fca5a5;
  --remove-ink: #991b1b;
  --guess: #ede9fe;
  --guess-ink: #5b21b6;
  --hint: var(--guess);
  --hint-ink: var(--guess-ink);
  --shadow: 0 18px 48px rgba(15, 23, 42, 0.1);
  --radius: 20px;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100%;
  padding: env(safe-area-inset-top, 0) env(safe-area-inset-right, 0) env(safe-area-inset-bottom, 0) env(safe-area-inset-left, 0);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-optical-sizing: auto;
  background: radial-gradient(circle at top left, #dbeafe 0, transparent 34rem), var(--bg);
  color: var(--ink);
}

button,
input,
select {
  font: inherit;
}

button {
  cursor: pointer;
  touch-action: manipulation;
}

a:focus-visible,
button:focus-visible,
input:focus-visible,
select:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.35);
  outline-offset: 3px;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 1000;
  transform: translateY(-180%);
  border-radius: 999px;
  padding: 10px 14px;
  background: var(--accent);
  color: #fff;
  font-weight: 900;
  text-decoration: none;
  box-shadow: var(--shadow);
}

.skip-link:focus {
  transform: translateY(0);
}

.app-shell {
  width: min(1320px, calc(100% - 28px));
  margin: 0 auto;
  padding: 14px 0 28px;
}

.primary-workspace {
  display: grid;
  grid-template-columns: minmax(420px, 0.94fr) minmax(420px, 1.06fr);
  gap: 18px;
  align-items: stretch;
}

.right-workspace {
  display: grid;
  grid-template-rows: minmax(0, 1fr) auto;
  gap: 18px;
  min-height: 100%;
}

.support-workspace {
  min-width: 0;
  display: grid;
  grid-template-columns: 1fr;
  gap: 18px;
  align-items: start;
  margin-top: 18px;
}

.card,
.board-panel,
.walkthrough-panel {
  min-width: 0;
  background: rgba(255, 255, 255, 0.92);
  border: 1px solid rgba(215, 222, 234, 0.95);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 18px;
}

.walkthrough-panel {
  min-height: 0;
  overflow: auto;
}

.panel-heading {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: start;
  margin-bottom: 14px;
}

.panel-heading.compact {
  margin-bottom: 12px;
}

.status-heading {
  align-items: center;
  flex-direction: row;
  justify-content: space-between;
  gap: 12px;
}

.status-heading .api-status-mini {
  margin-left: auto;
}

.section-helper {
  margin: 6px 0 0;
  color: var(--muted);
  line-height: 1.45;
}

.board-heading {
  align-items: center;
}

h1,
h2 {
  margin: 0;
  line-height: 1.08;
}

h1,
h2 {
  font-size: clamp(1.12rem, 1.7vw, 1.45rem);
  letter-spacing: -0.03em;
}

.board-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: flex-end;
}

.board-status-pill,
.step-pill,
.pill-toggle,
.pill-action {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  padding: 7px 10px;
  background: var(--surface-soft);
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 800;
  line-height: 1;
  min-height: 32px;
}

.pill-toggle,
.pill-action {
  border: 1px solid var(--line);
  appearance: none;
}

.pill-toggle.is-on {
  background: var(--accent-soft);
  border-color: rgba(37, 99, 235, 0.35);
  color: var(--accent-strong);
}

.pill-toggle:focus-visible,
.pill-action:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.25);
  outline-offset: 2px;
}

.pill-action {
  background: transparent;
}

.pill-action:hover,
.pill-toggle:hover {
  border-color: var(--accent);
}

.mobile-walkthrough-nav {
  display: none;
  align-items: center;
  justify-content: space-between;
  gap: 6px;
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 4px 6px;
  background: rgba(255, 255, 255, 0.72);
  color: var(--muted);
  box-shadow: none;
  font-size: 0.86rem;
  font-weight: 800;
  line-height: 1;
  min-height: 44px;
  white-space: nowrap;
}

.mobile-step-count {
  color: var(--ink);
  flex: 0 0 56px;
  min-width: 56px;
  text-align: center;
  font-size: 0.88rem;
  font-weight: 900;
  padding: 7px 6px;
  border-radius: 10px;
  background: transparent;
  border: 0;
}

.mobile-step-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex: 1 1 0;
  min-width: 40px;
  min-height: 36px;
  border: 0;
  border-radius: 10px;
  background: transparent;
  color: var(--brand-deep);
  font-size: 0.92rem;
  font-weight: 950;
  line-height: 1;
  padding: 0 8px;
  -webkit-tap-highlight-color: transparent;
}

@media (hover: hover) {
  .mobile-step-button:hover:not(:disabled) {
    background: var(--surface-soft);
    color: var(--accent-strong);
  }
}

.mobile-step-button:disabled {
  opacity: 0.42;
  cursor: not-allowed;
}

.mobile-step-button:active,
.mobile-step-button:focus:not(:focus-visible) {
  background: transparent;
  outline: 0;
}

.mobile-step-button:focus-visible {
  outline: 2px solid rgba(37, 99, 235, 0.32);
  outline-offset: 1px;
}

.board-wrap {
  width: 100%;
  display: flex;
  justify-content: center;
}

.sudoku-board {
  width: min(100%, 560px);
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  border: 3px solid var(--line-strong);
  border-radius: 16px;
  overflow: hidden;
  background: var(--line-strong);
}

.sudoku-cell {
  width: 100%;
  height: 100%;
  border: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  text-align: center;
  font-size: clamp(1.1rem, 4.4vw, 2rem);
  font-weight: 800;
  outline: none;
  transition: background 0.15s ease, box-shadow 0.15s ease, color 0.15s ease;
  touch-action: manipulation;
  -moz-appearance: textfield;
}

.sudoku-cell::-webkit-outer-spin-button,
.sudoku-cell::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.sudoku-cell:nth-child(3n) {
  border-right: 3px solid var(--line-strong);
}

.sudoku-cell:nth-child(9n) {
  border-right: 0;
}

.sudoku-cell:nth-child(n + 19):nth-child(-n + 27),
.sudoku-cell:nth-child(n + 46):nth-child(-n + 54) {
  border-bottom: 3px solid var(--line-strong);
}

.sudoku-cell:nth-child(n + 73) {
  border-bottom: 0;
}

.sudoku-cell.is-given {
  background-color: var(--given-bg);
  color: var(--given-ink);
}

.sudoku-cell.is-highlight {
  background-image: repeating-linear-gradient(135deg, var(--assist-line) 0, var(--assist-line) 7px, transparent 7px, transparent 14px);
}

.sudoku-cell.is-highlight.is-value-line {
  background-image: repeating-linear-gradient(135deg, var(--value-line) 0, var(--value-line) 7px, transparent 7px, transparent 14px);
}

.sudoku-cell.is-highlight.is-value-line.has-blue-overlap-value {
  background-image: repeating-linear-gradient(135deg, var(--assist-line) 0, var(--assist-line) 7px, transparent 7px, transparent 14px);
}

.sudoku-cell.is-placed,
.sudoku-cell.is-restored {
  background-color: var(--good);
  color: var(--good-ink);
}

.sudoku-cell.is-hint {
  background-color: var(--hint);
  color: var(--hint-ink);
}

.sudoku-cell.is-guessed {
  background-color: var(--guess);
  color: var(--guess-ink);
}

.sudoku-cell.is-persisted-guess,
.sudoku-cell.is-persisted-hint {
  color: var(--guess-ink);
}

.sudoku-cell.is-removed,
.sudoku-cell.is-failed {
  background-color: var(--remove);
  color: var(--remove-ink);
}

.sudoku-cell.is-conflict {
  background-color: var(--bad);
  color: var(--bad-ink);
}

.sudoku-cell.is-active {
  box-shadow: inset 0 0 0 4px var(--accent);
  z-index: 2;
}

.sudoku-cell-slot {
  position: relative;
  min-width: 0;
  min-height: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  overflow: hidden;
}

.sudoku-cell-slot:nth-child(3n) {
  border-right: 3px solid var(--line-strong);
}

.sudoku-cell-slot:nth-child(9n) {
  border-right: 0;
}

.sudoku-cell-slot:nth-child(n + 19):nth-child(-n + 27),
.sudoku-cell-slot:nth-child(n + 46):nth-child(-n + 54) {
  border-bottom: 3px solid var(--line-strong);
}

.sudoku-cell-slot:nth-child(n + 73) {
  border-bottom: 0;
}

.sudoku-cell-slot .sudoku-cell {
  position: absolute;
  inset: 0;
  z-index: 2;
  border: 0;
  background: transparent;
  color: inherit;
}

.sudoku-cell-slot .sudoku-cell.is-active {
  box-shadow: none;
}

.sudoku-cell-slot.is-given {
  background-color: var(--given-bg);
  color: var(--given-ink);
}

.sudoku-cell-slot.is-highlight {
  background-image: repeating-linear-gradient(135deg, var(--assist-line) 0, var(--assist-line) 7px, transparent 7px, transparent 14px);
}

.sudoku-cell-slot.is-highlight.is-value-line {
  background-image: repeating-linear-gradient(135deg, var(--value-line) 0, var(--value-line) 7px, transparent 7px, transparent 14px);
}

.sudoku-cell-slot.is-highlight.is-value-line.has-blue-overlap-value {
  background-image: repeating-linear-gradient(135deg, var(--assist-line) 0, var(--assist-line) 7px, transparent 7px, transparent 14px);
}

.sudoku-cell-slot.is-value-line {
  background-image: repeating-linear-gradient(135deg, var(--value-line) 0, var(--value-line) 7px, transparent 7px, transparent 14px);
}

.sudoku-cell-slot.is-value-match::after {
  content: '';
  position: absolute;
  inset: 7px;
  border-radius: 999px;
  border: 2px solid var(--value-match);
  pointer-events: none;
  z-index: 3;
}

.sudoku-cell-slot.is-placed,
.sudoku-cell-slot.is-restored {
  background-color: var(--good);
  color: var(--good-ink);
}

.sudoku-cell-slot.is-hint {
  background-color: var(--hint);
  color: var(--hint-ink);
}

.sudoku-cell-slot.is-guessed,
.sudoku-cell-slot.is-candidate-target {
  background-color: var(--guess);
  color: var(--guess-ink);
}

.sudoku-cell-slot.is-persisted-guess,
.sudoku-cell-slot.is-persisted-hint {
  color: var(--guess-ink);
}

.sudoku-cell-slot.is-removed,
.sudoku-cell-slot.is-failed {
  background-color: var(--remove);
  color: var(--remove-ink);
}

.sudoku-cell-slot.is-conflict {
  background-color: var(--bad);
  color: var(--bad-ink);
}

.sudoku-cell-slot.is-active {
  box-shadow: inset 0 0 0 4px var(--accent);
  z-index: 2;
}

.sudoku-cell-slot.has-candidates .sudoku-cell {
  color: transparent;
  caret-color: var(--ink);
}

.candidate-grid {
  position: absolute;
  inset: 8%;
  z-index: 1;
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  grid-template-rows: repeat(3, minmax(0, 1fr));
  place-items: center;
  color: var(--muted);
  font-size: clamp(0.5rem, 1.45vw, 0.85rem);
  font-weight: 800;
  line-height: 1;
  pointer-events: none;
}

.candidate-mark {
  opacity: 0;
}

.candidate-mark.is-visible {
  opacity: 1;
}

.number-pad {
  width: min(100%, 560px);
  margin: 14px auto 0;
  display: grid;
  grid-template-columns: repeat(10, minmax(0, 1fr));
  gap: 8px;
}

.number-pad button {
  min-height: 44px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--surface-soft);
  color: var(--ink);
  font-weight: 800;
}

.number-pad button:last-child {
  font-size: 0.82rem;
}

.actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 14px;
}

.primary-actions {
  justify-content: center;
}

.solve-options {
  max-width: 520px;
  margin: 14px auto 0;
}

.loader-options {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: stretch;
  margin-bottom: 14px;
}

.checkbox-option {
  display: flex;
  gap: 12px;
  align-items: flex-start;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 12px 14px;
  background: var(--surface-soft);
  color: var(--ink);
  cursor: pointer;
}

.checkbox-option input {
  width: 18px;
  height: 18px;
  margin-top: 2px;
  accent-color: var(--accent);
}

.checkbox-option span,
.checkbox-option small {
  display: block;
}

.checkbox-option strong {
  display: block;
  font-size: 0.95rem;
}

.checkbox-option small {
  margin-top: 3px;
  color: var(--muted);
  line-height: 1.35;
}

.checkbox-option.compact-option {
  max-width: 420px;
  padding: 10px 12px;
}

.checkbox-option.compact-option strong {
  font-size: 0.9rem;
}

.button {
  border: 1px solid var(--line);
  border-radius: 14px;
  min-height: 44px;
  padding: 11px 14px;
  background: var(--surface);
  color: var(--ink);
  font-weight: 800;
  text-decoration: none;
  transition: transform 0.12s ease, background 0.12s ease, border-color 0.12s ease;
}

.button:hover:not(:disabled),
.number-pad button:hover:not(:disabled) {
  transform: translateY(-1px);
  border-color: var(--accent);
}

.button:disabled,
.number-pad button:disabled {
  cursor: not-allowed;
  opacity: 0.55;
}

.button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.button.primary:hover:not(:disabled) {
  background: var(--accent-strong);
}

.button.ghost {
  background: transparent;
}

.field-label {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 0.9rem;
  font-weight: 700;
}

.select {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 14px;
  min-height: 44px;
  padding: 12px;
  background: var(--surface);
  color: var(--ink);
}

.file-input,
.scan-puzzle-text {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 14px;
  min-height: 44px;
  padding: 12px;
  background: var(--surface);
  color: var(--ink);
}

.scan-puzzle-text {
  min-height: 84px;
  resize: vertical;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  line-height: 1.45;
}

.scan-import-layout {
  display: grid;
  grid-template-columns: minmax(240px, 0.78fr) minmax(320px, 1.22fr);
  gap: 16px;
  align-items: start;
}

.scan-import-source,
.scan-import-review {
  min-width: 0;
}

.scan-preview {
  display: block;
  width: 100%;
  max-height: 420px;
  object-fit: contain;
  margin-top: 12px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface-soft);
}

.scan-preview[hidden] {
  display: none;
}


.scan-prep-actions {
  margin-top: 12px;
}

.scan-prep-panel {
  margin-top: 14px;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 12px;
  background: var(--surface-soft);
}

.scan-prep-panel[hidden] {
  display: none;
}

.scan-prep-heading h3 {
  margin: 0 0 4px;
  font-size: 0.95rem;
  letter-spacing: -0.02em;
}

.scan-detected-canvas,
.scan-prepared-canvas {
  display: block;
  width: min(100%, 420px);
  aspect-ratio: 1;
  border: 2px solid var(--line-strong);
  border-radius: 14px;
  background: var(--surface);
  margin: 12px 0;
}

.scan-detected-canvas {
  aspect-ratio: auto;
  max-height: 360px;
  object-fit: contain;
}

.scan-mapping-summary,
.scan-ocr-summary {
  width: min(100%, 420px);
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
  padding: 10px 12px;
}

.scan-review-heading {
  display: flex;
  justify-content: space-between;
  align-items: start;
  gap: 12px;
  margin-bottom: 10px;
}

.scan-review-heading h3 {
  margin: 0;
  font-size: 1rem;
  letter-spacing: -0.02em;
}

.scan-review-count {
  flex: 0 0 auto;
  border-radius: 999px;
  padding: 7px 10px;
  background: var(--surface-soft);
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 850;
  line-height: 1;
}

.scan-review-grid {
  width: min(100%, 430px);
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  border: 3px solid var(--line-strong);
  border-radius: 14px;
  overflow: hidden;
  background: var(--line-strong);
  margin-bottom: 14px;
}

.scan-cell {
  min-width: 0;
  min-height: 0;
  width: 100%;
  height: 100%;
  border: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  text-align: center;
  font-size: clamp(1rem, 3vw, 1.65rem);
  font-weight: 800;
  outline: none;
  transition: background 0.15s ease, box-shadow 0.15s ease, color 0.15s ease;
  touch-action: manipulation;
  -moz-appearance: textfield;
}

.scan-cell::-webkit-outer-spin-button,
.scan-cell::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.scan-cell:nth-child(3n) {
  border-right: 3px solid var(--line-strong);
}

.scan-cell:nth-child(9n) {
  border-right: 0;
}

.scan-cell:nth-child(n + 19):nth-child(-n + 27),
.scan-cell:nth-child(n + 46):nth-child(-n + 54) {
  border-bottom: 3px solid var(--line-strong);
}

.scan-cell:nth-child(n + 73) {
  border-bottom: 0;
}

.scan-cell.is-filled {
  background: var(--given-bg);
  color: var(--given-ink);
}

.scan-cell.is-conflict {
  background: var(--bad);
  color: var(--bad-ink);
}

.scan-cell.is-ocr-recognized {
  box-shadow: inset 0 0 0 2px rgba(124, 58, 237, 0.35);
}

.scan-cell.is-ocr-low-confidence {
  background: var(--guess-bg);
  color: var(--guess-ink);
}

.scan-cell.is-active {
  box-shadow: inset 0 0 0 4px var(--accent);
  z-index: 2;
}

.scan-actions {
  margin-bottom: 12px;
}

.scan-import-status {
  margin-top: 12px;
}

.status-box {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 14px;
  background: var(--surface-soft);
  color: var(--muted);
  line-height: 1.55;
}

.status-box.is-ok {
  background: var(--good);
  border-color: #86efac;
  color: var(--good-ink);
}

.status-box.is-warn {
  background: var(--warn);
  border-color: #fde68a;
  color: var(--warn-ink);
}

.status-box.is-bad {
  background: var(--bad);
  border-color: #fecaca;
  color: var(--bad-ink);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin: 14px 0 0;
}

.stats-grid div {
  border: 1px solid var(--line);
  border-radius: 14px;
  min-height: 44px;
  padding: 12px;
  background: var(--surface-soft);
}

.stats-grid dt {
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.stats-grid dd {
  margin: 4px 0 0;
  font-size: 1.18rem;
  font-weight: 900;
}

.button.small {
  padding: 8px 12px;
  font-size: 0.82rem;
}

.recent-panel {
  margin-top: 14px;
  max-width: 100%;
  overflow: hidden;
  border: 1px solid var(--line);
  border-radius: 18px;
  min-height: 44px;
  padding: 12px;
  background: var(--surface);
}

.recent-panel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 12px;
}

.recent-panel-header h3 {
  margin: 0;
  font-size: 0.98rem;
}

.recent-list {
  max-width: 100%;
  min-width: 0;
  display: grid;
  grid-template-columns: repeat(auto-fill, 158px);
  justify-content: start;
  align-items: start;
  gap: 12px;
}

.recent-message {
  grid-column: 1 / -1;
}

.recent-item {
  width: 158px;
  min-height: 246px;
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 10px;
  background: var(--surface-soft);
  text-align: left;
  color: var(--ink);
}

.recent-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}

.recent-actions .button {
  flex: 1 1 auto;
  padding: 7px 8px;
  font-size: 0.76rem;
}

.recent-item:hover {
  border-color: var(--accent);
}

.recent-item strong {
  display: block;
  margin-bottom: 8px;
  font-size: 0.9rem;
}

.recent-meta {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
  margin-top: 8px;
}

.mini-board {
  width: 100%;
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  border: 2px solid var(--line-strong);
  border-radius: 8px;
  overflow: hidden;
  background: var(--line-strong);
}

.mini-cell {
  display: grid;
  place-items: center;
  min-width: 0;
  min-height: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  font-size: clamp(0.42rem, 1.5vw, 0.72rem);
  font-weight: 800;
  line-height: 1;
}

.mini-cell:nth-child(3n) {
  border-right: 2px solid var(--line-strong);
}

.mini-cell:nth-child(9n) {
  border-right: 0;
}

.mini-cell:nth-child(n + 19):nth-child(-n + 27),
.mini-cell:nth-child(n + 46):nth-child(-n + 54) {
  border-bottom: 2px solid var(--line-strong);
}

.mini-cell:nth-child(n + 73) {
  border-bottom: 0;
}

.mini-cell.is-empty {
  color: transparent;
}

.mini-cube {
  width: min(100%, 92px);
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  border: 2px solid var(--line-strong);
  border-radius: 8px;
  overflow: hidden;
  background: var(--line-strong);
  margin: 0 auto;
}

.mini-cube-cell {
  display: grid;
  place-items: center;
  min-width: 0;
  min-height: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  background: var(--surface);
  color: var(--ink);
  font-size: 0.86rem;
  font-weight: 800;
  line-height: 1;
}

.mini-cube-cell:nth-child(3n) {
  border-right: 0;
}

.mini-cube-cell:nth-child(n + 7) {
  border-bottom: 0;
}

.mini-cube-cell.is-empty {
  color: transparent;
}



.logic-detail {
  margin-top: 12px;
  border: 1px solid var(--line);
  border-radius: 14px;
  min-height: 44px;
  padding: 12px;
  background: var(--surface);
}

.logic-detail strong {
  display: block;
  margin-bottom: 8px;
  color: var(--ink);
}

.logic-detail ol {
  margin: 0;
  padding-left: 22px;
  display: grid;
  gap: 8px;
}

.logic-detail li {
  color: var(--muted);
  line-height: 1.45;
}

.logic-placement {
  display: inline-block;
  margin-right: 6px;
  color: var(--ink);
  font-weight: 800;
}

.technique-line {
  margin: 0 0 7px;
  color: var(--accent-strong);
  font-size: 0.84rem;
  font-weight: 750;
}

.contradiction-detail {
  margin: 12px 0;
  border: 1px solid #fecaca;
  border-radius: 14px;
  min-height: 44px;
  padding: 12px;
  background: #fff7f7;
  color: var(--bad-ink);
}

.contradiction-detail strong {
  display: block;
  margin-bottom: 6px;
  color: var(--bad-ink);
}

.contradiction-detail p {
  margin: 0 0 8px;
}

.contradiction-detail ul {
  margin: 0;
  padding-left: 18px;
}

.guess-help {
  margin-top: 14px;
  display: grid;
  gap: 14px;
}

.guess-candidates,
.guess-combinations {
  border-top: 1px solid var(--line);
  padding-top: 12px;
}

.guess-candidates strong,
.guess-combinations strong {
  display: block;
  margin-bottom: 8px;
  color: var(--ink);
}

.guess-candidates ul {
  margin: 0;
  padding-left: 18px;
}

.combo-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(96px, 1fr));
  gap: 10px;
  max-height: 360px;
  overflow: auto;
  padding: 2px 2px 6px;
}

.combo-option {
  display: block;
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 8px;
  background: var(--surface);
  color: var(--ink);
  text-align: left;
  cursor: pointer;
}

.combo-option:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.combo-option.is-success {
  border-color: var(--line);
  background: var(--surface);
}

.combo-option.is-success:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.combo-option.is-active-choice {
  border-color: var(--guess-ink);
  background: var(--guess);
  color: var(--guess-ink);
  box-shadow: none;
}

.combo-option.is-active-choice:hover {
  transform: none;
}

.combo-option.is-reviewed,
.combo-option.is-reviewed:hover,
.combo-option:disabled {
  background: var(--surface-soft);
  border-color: var(--line);
  color: var(--muted);
  cursor: not-allowed;
  opacity: 0.72;
  transform: none;
}

.combo-option.is-reviewed .mini-cube,
.combo-option:disabled .mini-cube {
  opacity: 0.72;
}

.combo-option > strong {
  display: block;
  font-size: 0.78rem;
  margin-bottom: 6px;
}

.mini-cell.is-combo,
.mini-cube-cell.is-combo {
  background: var(--guess);
  color: var(--guess-ink);
}

.walkthrough-header {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  align-items: start;
}

.walkthrough-header p:last-child {
  margin: 8px 0 0;
  color: var(--muted);
  line-height: 1.5;
}

.walkthrough-controls {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.walkthrough-controls .button {
  flex: 1 1 auto;
}

.step-detail {
  min-height: 138px;
  margin-top: 16px;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 16px;
  background: var(--surface-soft);
}

.step-detail p {
  margin: 10px 0 0;
  line-height: 1.55;
}

.step-detail ul {
  margin: 10px 0 0;
  padding-left: 18px;
  color: var(--muted);
}

.timeline {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  max-height: 230px;
  overflow: auto;
  padding: 16px 2px 2px;
}

.timeline button {
  flex: 0 0 auto;
  min-width: 50px;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 8px 10px;
  background: var(--surface);
  color: var(--muted);
  font-weight: 900;
}

.timeline button.is-current {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.timeline button.is-guess {
  background: var(--guess);
  color: var(--guess-ink);
}

.timeline button.is-rewind,
.timeline button.is-branch_failed,
.timeline button.is-manual_clear {
  background: var(--remove);
  border-color: var(--remove-border);
  color: var(--remove-ink);
}

.timeline button.is-logical_fill,
.timeline button.is-branch_restore,
.timeline button.is-manual_entry {
  background: var(--good);
  color: var(--good-ink);
}

.timeline button.is-manual_start,
.timeline button.is-solved {
  /* Manual replay start and final solved states intentionally use the same neutral/current styling as solver initial-state steps. */
}

.timeline button.is-hint {
  background: var(--guess);
  color: var(--guess-ink);
}

.help-card {
  margin-top: 0;
}

.help-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.help-grid div {
  border: 1px solid var(--line);
  border-radius: 16px;
  padding: 14px;
  background: var(--surface-soft);
}

.help-grid h3 {
  margin: 0 0 8px;
  font-size: 0.96rem;
  letter-spacing: -0.01em;
}

.help-grid p {
  margin: 0;
  color: var(--muted);
  line-height: 1.48;
  font-size: 0.92rem;
}

.terminology-card {
  grid-column: 1 / -1;
}

.terminology-board {
  display: grid;
  grid-template-columns: minmax(28px, auto) repeat(9, minmax(24px, 1fr));
  gap: 2px;
  max-width: 520px;
  margin-top: 0.7rem;
  font-size: 0.76rem;
  color: var(--text);
}

.term-corner,
.term-col-label,
.term-row-label,
.term-cell {
  min-height: 24px;
  display: grid;
  place-items: center;
  border-radius: 7px;
}

.term-col-label,
.term-row-label {
  font-weight: 800;
  color: var(--muted);
  background: rgba(15, 23, 42, 0.05);
}

.term-cell {
  background: rgba(255, 255, 255, 0.78);
  border: 1px solid rgba(15, 23, 42, 0.08);
  font-weight: 700;
  color: rgba(15, 23, 42, 0.7);
}

.term-box-1,
.term-box-3,
.term-box-5,
.term-box-7,
.term-box-9 {
  background: rgba(37, 99, 235, 0.06);
}

.term-box-2,
.term-box-4,
.term-box-6,
.term-box-8 {
  background: rgba(245, 158, 11, 0.08);
}

.term-cell.is-box-label {
  color: var(--brand-deep);
  border-color: rgba(37, 99, 235, 0.2);
}

.term-cell.is-example-cell {
  color: var(--danger);
  border-color: rgba(220, 38, 38, 0.35);
  box-shadow: 0 0 0 2px rgba(220, 38, 38, 0.1) inset;
  background: rgba(254, 242, 242, 0.95);
}

.assist-help-card {
  grid-column: span 2;
}

.assist-help-card p + p {
  margin-top: 8px;
}

.assist-example-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 12px;
}

.assist-example {
  display: grid;
  gap: 8px;
  min-width: 0;
}

.assist-example-title {
  color: var(--ink);
  font-size: 0.8rem;
  font-weight: 850;
  line-height: 1.25;
}

.assist-mini-board {
  display: grid;
  grid-template-columns: repeat(9, minmax(0, 1fr));
  gap: 1px;
  width: min(100%, 190px);
  aspect-ratio: 1;
  border: 2px solid var(--line-strong);
  background: var(--line-strong);
  border-radius: 10px;
  overflow: hidden;
}

.assist-mini-board span {
  position: relative;
  display: grid;
  place-items: center;
  min-width: 0;
  min-height: 0;
  background: var(--surface);
  color: var(--ink);
  font-size: 0.64rem;
  font-weight: 900;
}

.assist-mini-board span:nth-child(3n) {
  border-right: 2px solid var(--line-strong);
}

.assist-mini-board span:nth-child(9n) {
  border-right: 0;
}

.assist-mini-board span:nth-child(n + 19):nth-child(-n + 27),
.assist-mini-board span:nth-child(n + 46):nth-child(-n + 54) {
  border-bottom: 2px solid var(--line-strong);
}

.assist-mini-board span:nth-child(n + 73) {
  border-bottom: 0;
}

.assist-mini-board .is-blue {
  background-image: repeating-linear-gradient(135deg, var(--assist-line) 0, var(--assist-line) 5px, transparent 5px, transparent 10px);
}

.assist-mini-board .is-yellow {
  background-image: repeating-linear-gradient(135deg, var(--value-line) 0, var(--value-line) 5px, transparent 5px, transparent 10px);
}

.assist-mini-board .is-selected {
  box-shadow: inset 0 0 0 3px var(--accent);
  background-color: var(--surface);
}

.assist-mini-board .is-red::after {
  content: '';
  position: absolute;
  inset: 4px;
  border: 2px solid var(--bad-ink);
  border-radius: 999px;
}

.footer {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 12px 16px;
  margin-top: 22px;
  color: var(--muted);
  font-size: 0.9rem;
}


.api-status-mini {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  flex: 0 0 auto;
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 7px 10px;
  background: var(--surface-soft);
  white-space: nowrap;
}

.api-status-mini strong {
  color: var(--ink);
}

.footer-action {
  border: 1px solid var(--line);
  border-radius: 999px;
  min-height: 36px;
  padding: 8px 12px;
  background: var(--surface);
  color: var(--ink);
  font-size: 0.84rem;
  font-weight: 800;
}

.footer-action:hover:not(:disabled) {
  border-color: var(--accent);
}

.status-dot {
  width: 10px;
  height: 10px;
  flex: 0 0 auto;
  border-radius: 999px;
  background: #f59e0b;
  box-shadow: 0 0 0 4px rgba(245, 158, 11, 0.15);
}

.status-dot.is-ok {
  background: #22c55e;
  box-shadow: 0 0 0 4px rgba(34, 197, 94, 0.15);
}

.status-dot.is-bad {
  background: #ef4444;
  box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.15);
}

@media (max-width: 1100px) {
  .primary-workspace,
  .support-workspace {
    grid-template-columns: 1fr;
  }

  .right-workspace {
    grid-template-rows: auto auto;
  }

  .walkthrough-panel {
    max-height: none;
  }

  .stats-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .help-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .scan-import-layout {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .app-shell {
    width: min(100% - 20px, 1180px);
    padding-top: 10px;
  }

  .board-panel,
  .card,
  .walkthrough-panel {
    padding: 14px;
    border-radius: 18px;
  }

  .panel-heading {
    flex-direction: column;
  }

  .status-heading {
    flex-direction: row;
    align-items: center;
  }

  .status-heading .api-status-mini {
    padding: 6px 8px;
    font-size: 0.78rem;
  }

  .board-meta {
    justify-content: flex-start;
    flex-wrap: nowrap;
    width: 100%;
    max-width: 100%;
    min-width: 0;
    overflow-x: auto;
    overflow-y: hidden;
    overscroll-behavior-inline: contain;
    -webkit-overflow-scrolling: touch;
  }

  .board-meta > * {
    flex: 0 0 auto;
    white-space: nowrap;
  }

  .board-status-pill,
  .pill-toggle,
  .pill-action {
    padding: 6px 8px;
    font-size: 0.76rem;
    min-height: 30px;
  }

  .board-meta.is-mobile-walkthrough {
    width: 100%;
  }

  .board-meta.is-mobile-walkthrough #boardMode {
    display: none;
  }

  .board-meta.is-mobile-walkthrough .mobile-walkthrough-nav:not([hidden]) {
    display: inline-flex;
    flex: 1 1 100%;
    max-width: 100%;
  }

  .board-panel.is-mobile-review .board-heading {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: center;
    column-gap: 10px;
    row-gap: 8px;
  }

  .board-panel.is-mobile-review .board-heading > div:first-child {
    grid-column: 1;
    min-width: 0;
  }

  .board-panel.is-mobile-review .board-meta.is-mobile-walkthrough {
    display: contents;
    width: auto;
    max-width: none;
    overflow: visible;
  }

  .board-panel.is-mobile-review #assistHighlights {
    grid-column: 2;
    justify-self: end;
    min-width: 0;
  }

  .board-panel.is-mobile-review .mobile-walkthrough-nav:not([hidden]) {
    grid-column: 1 / -1;
    display: inline-flex;
    width: 100%;
    max-width: 100%;
    margin-top: 0;
  }

  .number-pad {
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 10px;
  }

  .number-pad button {
    min-height: 48px;
  }

  .actions .button {
    flex: 1 1 auto;
  }

  
.scan-prep-actions {
  margin-top: 12px;
}

.scan-prep-panel {
  margin-top: 14px;
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 12px;
  background: var(--surface-soft);
}

.scan-prep-panel[hidden] {
  display: none;
}

.scan-prep-heading h3 {
  margin: 0 0 4px;
  font-size: 0.95rem;
  letter-spacing: -0.02em;
}

.scan-detected-canvas,
.scan-prepared-canvas {
  display: block;
  width: min(100%, 420px);
  aspect-ratio: 1;
  border: 2px solid var(--line-strong);
  border-radius: 14px;
  background: var(--surface);
  margin: 12px 0;
}

.scan-detected-canvas {
  aspect-ratio: auto;
  max-height: 360px;
  object-fit: contain;
}

.scan-mapping-summary,
.scan-ocr-summary {
  width: min(100%, 420px);
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
  padding: 10px 12px;
}

.scan-review-heading {
    flex-direction: column;
  }

  .scan-review-grid {
    width: 100%;
  }

  .walkthrough-controls {
    display: none;
  }

  .stats-grid {
    grid-template-columns: repeat(auto-fit, minmax(112px, 1fr));
    gap: 8px;
  }

  .stats-grid div {
    min-height: 40px;
    padding: 10px;
  }

  .stats-grid dd {
    font-size: 1.05rem;
  }

  .help-grid {
    grid-template-columns: 1fr;
  }

  .assist-help-card {
    grid-column: 1;
  }

  .assist-example-grid {
    grid-template-columns: 1fr;
  }

  .recent-list {
    grid-template-columns: repeat(auto-fill, 142px);
  }

  .recent-item {
    width: 142px;
    min-height: 228px;
  }

  .mini-cell {
    font-size: 0.7rem;
  }

  .recent-panel {
    overflow: hidden;
  }

  .recent-list {
    display: flex;
    flex-wrap: nowrap;
    gap: 12px;
    width: 100%;
    max-width: 100%;
    min-width: 0;
    overflow-x: auto;
    overflow-y: hidden;
    overscroll-behavior-inline: contain;
    scroll-snap-type: x proximity;
    padding-bottom: 8px;
    -webkit-overflow-scrolling: touch;
  }

  .recent-message {
    flex: 1 0 100%;
  }

  .recent-item {
    flex: 0 0 min(150px, 74vw);
    width: min(150px, 74vw);
    min-width: 0;
    min-height: 232px;
    scroll-snap-align: start;
  }

  .board-panel.is-mobile-review #candidateMode,
  .board-panel.is-mobile-review #clearCandidatesButton,
  .board-panel.is-mobile-review .number-pad,
  .board-panel.is-mobile-review .primary-actions {
    display: none;
  }

  .walkthrough-header {
    gap: 6px;
  }

  #walkthroughSummary {
    display: none;
  }

  .step-detail {
    min-height: 0;
    padding: 0;
    margin-top: 8px;
    border: 0;
    border-radius: 0;
    background: transparent;
  }

  .step-detail .step-pill {
    min-height: 0;
    padding: 0;
    background: transparent;
    color: var(--accent-strong);
    justify-content: flex-start;
    font-size: 0.8rem;
    letter-spacing: 0.01em;
  }

  .step-detail p,
  .step-detail ul {
    margin-top: 5px;
  }

  .step-detail p {
    line-height: 1.42;
  }

  .logic-detail,
  .contradiction-detail,
  .guess-candidates,
  .guess-combinations {
    margin-top: 7px;
  }

  .logic-detail,
  .contradiction-detail {
    padding: 10px;
    border-radius: 12px;
  }

  .logic-detail strong,
  .contradiction-detail strong,
  .guess-candidates strong,
  .guess-combinations strong {
    margin-bottom: 5px;
  }

  .logic-detail ol {
    gap: 6px;
    padding-left: 20px;
  }

  .timeline {
    flex-wrap: nowrap;
    gap: 6px;
    max-height: none;
    overflow-x: auto;
    overflow-y: hidden;
    scroll-snap-type: x proximity;
    overscroll-behavior-inline: contain;
    padding: 10px 2px 2px;
    -webkit-overflow-scrolling: touch;
  }

  .timeline button {
    min-width: 44px;
    padding: 7px 10px;
    scroll-snap-align: center;
  }

  .guess-combinations {
    overflow: hidden;
  }

  .combo-grid {
    display: flex;
    flex-wrap: nowrap;
    grid-template-columns: none;
    gap: 10px;
    max-height: none;
    overflow-x: auto;
    overflow-y: hidden;
    overscroll-behavior-inline: contain;
    scroll-snap-type: x proximity;
    padding: 2px 2px 8px;
    -webkit-overflow-scrolling: touch;
  }

  .combo-option {
    flex: 0 0 104px;
    width: 104px;
    min-width: 104px;
    scroll-snap-align: start;
  }


  .sudoku-cell-slot.is-value-match::after {
    inset: 4px;
  }
}


@media (hover: none) {
  .button:hover:not(:disabled),
  .number-pad button:hover:not(:disabled) {
    transform: none;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: 0.001ms !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media (max-width: 640px) {
  .terminology-board {
    font-size: 0.66rem;
    grid-template-columns: minmax(24px, auto) repeat(9, minmax(20px, 1fr));
    gap: 1px;
  }

  .term-corner,
  .term-col-label,
  .term-row-label,
  .term-cell {
    min-height: 21px;
    border-radius: 5px;
  }
}

body.manual-open {
  overflow: hidden;
}

.user-manual[hidden] {
  display: none;
}

.user-manual {
  position: fixed;
  inset: 0;
  z-index: 1000;
  background: linear-gradient(180deg, rgba(248, 250, 252, 0.98), rgba(239, 246, 255, 0.98));
  overflow: hidden;
  padding: max(16px, env(safe-area-inset-top)) max(12px, env(safe-area-inset-right)) max(18px, env(safe-area-inset-bottom)) max(12px, env(safe-area-inset-left));
}

.manual-shell {
  width: min(1180px, 100%);
  height: 100%;
  margin: 0 auto;
  display: grid;
  grid-template-rows: auto minmax(0, 1fr);
  gap: 14px;
}

.manual-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 18px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 22px;
  background: var(--surface);
  box-shadow: var(--shadow-soft);
}

.manual-header h2 {
  margin: 2px 0 6px;
  font-size: clamp(1.45rem, 4vw, 2.15rem);
  letter-spacing: -0.04em;
}

.manual-header p {
  margin: 0;
  color: var(--muted);
  line-height: 1.45;
  max-width: 72ch;
}

.manual-kicker,
.manual-page-kicker {
  color: var(--brand-deep);
  font-size: 0.76rem;
  font-weight: 900;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.manual-layout {
  min-height: 0;
  display: grid;
  grid-template-columns: minmax(210px, 250px) minmax(0, 1fr);
  gap: 14px;
}

.manual-toc {
  min-height: 0;
  overflow: auto;
  display: grid;
  align-content: start;
  gap: 8px;
  padding: 12px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: rgba(255, 255, 255, 0.92);
  box-shadow: var(--shadow-soft);
}

.manual-toc button {
  width: 100%;
  border: 1px solid transparent;
  border-radius: 14px;
  background: transparent;
  color: var(--muted);
  font-weight: 850;
  text-align: left;
  padding: 10px 11px;
}

.manual-toc button:hover,
.manual-toc button:focus-visible,
.manual-toc button.is-active {
  color: var(--brand-deep);
  border-color: rgba(37, 99, 235, 0.18);
  background: var(--accent-soft);
}

.manual-main {
  min-width: 0;
  min-height: 0;
  overflow-y: auto;
  overflow-x: hidden;
  display: block;
  padding-right: 2px;
}

.manual-page-status {
  display: inline-block;
  margin-bottom: 12px;
  justify-self: start;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--muted);
  font-weight: 850;
  font-size: 0.84rem;
  padding: 7px 11px;
}

.manual-page[hidden] {
  display: none;
}

.manual-page {
  min-height: auto;
  display: grid;
  grid-template-columns: minmax(0, 0.88fr) minmax(320px, 1.12fr);
  gap: 18px;
  align-items: stretch;
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--surface);
  box-shadow: var(--shadow-soft);
}

.manual-page-copy h3 {
  margin: 4px 0 10px;
  font-size: clamp(1.35rem, 3vw, 2rem);
  letter-spacing: -0.03em;
}

.manual-page-copy p {
  margin: 0;
  color: var(--muted);
  line-height: 1.58;
}

.manual-page-copy p + p {
  margin-top: 12px;
}

.manual-visual {
  min-width: 0;
  align-self: start;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--surface-soft);
  padding: 16px;
}

.manual-grid-visual,
.manual-assist-page {
  display: grid;
  justify-items: center;
  gap: 12px;
}

.manual-board {
  display: grid;
  grid-template-columns: repeat(9, minmax(0, 1fr));
  width: min(100%, 360px);
  aspect-ratio: 1;
  border: 3px solid var(--line-strong);
  border-radius: 14px;
  overflow: hidden;
  background: var(--line-strong);
  margin-inline: auto;
}

.manual-cell.sudoku-cell-slot {
  display: grid;
  place-items: center;
  font-size: clamp(0.7rem, 2.4vw, 1.15rem);
  font-weight: 900;
}

.manual-cell.sudoku-cell-slot.is-active {
  box-shadow: inset 0 0 0 4px var(--accent);
  z-index: 2;
}

.manual-flow {
  display: grid;
  gap: 10px;
}

.manual-flow span {
  display: block;
  padding: 12px 14px;
  border-radius: 14px;
  background: var(--surface);
  border: 1px solid var(--line);
  color: var(--brand-deep);
  font-weight: 850;
}

.manual-control-visual {
  display: grid;
  place-items: center;
}

.manual-keypad {
  width: min(100%, 360px);
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
}

.manual-keypad span,
.manual-note-buttons button {
  min-height: 42px;
  border-radius: 13px;
  border: 1px solid var(--line);
  background: var(--surface);
  display: grid;
  place-items: center;
  font-weight: 900;
  color: var(--brand-deep);
}

.manual-keypad .wide {
  grid-column: 1 / -1;
}

.manual-keypad .ghost {
  color: var(--muted);
  background: rgba(255, 255, 255, 0.72);
}

.manual-note-demo {
  display: grid;
  justify-items: center;
  align-content: center;
  gap: 14px;
}

.manual-note-cell {
  position: relative;
  width: min(170px, 52vw);
  aspect-ratio: 1;
  border: 3px solid var(--accent);
  border-radius: 18px;
  background: var(--surface);
  overflow: hidden;
}

.manual-note-cell .candidate-grid {
  opacity: 1;
  z-index: 1;
}

.manual-note-buttons {
  display: grid;
  grid-template-columns: repeat(9, minmax(28px, 1fr));
  gap: 6px;
  width: min(100%, 380px);
}

.manual-note-buttons button.is-on {
  background: var(--guess);
  color: var(--guess-ink);
  border-color: rgba(124, 58, 237, 0.28);
}

.manual-two-up,
.manual-whatif-demo {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.manual-two-up h4 {
  margin: 0 0 8px;
  color: var(--brand-deep);
  font-size: 0.92rem;
}

.manual-example-card {
  min-width: 0;
  display: grid;
  gap: 8px;
}

.manual-real-example-pair .manual-board {
  width: min(100%, 300px);
}

.manual-real-example-pair .manual-visual-note {
  font-size: 0.86rem;
}

.manual-step-example {
  display: grid;
  align-content: center;
  gap: 10px;
}

.manual-step-example strong {
  font-size: 1.08rem;
}

.manual-step-example p,
.manual-visual-note {
  margin: 0;
  color: var(--muted);
  line-height: 1.48;
}

.manual-mini-stat {
  justify-self: start;
  border-radius: 999px;
  padding: 7px 10px;
  background: var(--accent-soft);
  color: var(--brand-deep);
  font-weight: 850;
  font-size: 0.82rem;
}

.manual-whatif-demo .combo-option {
  width: 100%;
}

.manual-whatif-demo .manual-visual-note {
  grid-column: 1 / -1;
}

.manual-mini-cube {
  width: min(100%, 112px);
  margin-top: 4px;
}

.manual-page-nav {
  display: flex;
  margin-top: 12px;
  justify-content: space-between;
  gap: 10px;
  padding-bottom: 2px;
}

@media (max-width: 900px) {
  .manual-layout {
    grid-template-columns: 1fr;
  }

  .manual-toc {
    display: flex;
    overflow-x: auto;
    overscroll-behavior-inline: contain;
  }

  .manual-toc button {
    flex: 0 0 auto;
    width: auto;
    white-space: nowrap;
  }

  .manual-page {
    grid-template-columns: 1fr;
    min-height: auto;
  }

  .manual-header {
    align-items: stretch;
    flex-direction: column;
  }

  .manual-two-up,
  .manual-whatif-demo {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .user-manual {
    padding: max(10px, env(safe-area-inset-top)) max(8px, env(safe-area-inset-right)) max(12px, env(safe-area-inset-bottom)) max(8px, env(safe-area-inset-left));
  }

  .manual-shell {
    gap: 10px;
  }

  .manual-header,
  .manual-page,
  .manual-toc {
    border-radius: 18px;
  }

  .manual-page {
    padding: 14px;
  }

  .manual-note-buttons {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .manual-page-nav .button {
    flex: 1 1 0;
  }
}

/* Milestone 9 final polish: native puzzle dropdown and manual learning path */
.puzzle-select {
  width: 100%;
  min-height: 48px;
  border: 1px solid var(--line);
  border-radius: 15px;
  background: var(--surface);
  color: var(--ink);
  font: inherit;
  font-weight: 800;
  padding: 0 42px 0 14px;
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.05);
}

.puzzle-select:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.22);
  border-color: rgba(37, 99, 235, 0.44);
}

.puzzle-select optgroup {
  color: var(--brand-deep);
  font-weight: 950;
}

.puzzle-select option {
  color: var(--ink);
  font-weight: 400;
}

@media (max-width: 900px) {
  .puzzle-select {
    min-height: 46px;
    border-radius: 14px;
    font-size: 1rem;
    padding-left: 12px;
  }
}

.manual-takeaway {
  border: 1px solid rgba(37, 99, 235, 0.18);
  border-radius: 15px;
  background: var(--accent-soft);
  padding: 10px 12px;
  color: var(--brand-deep) !important;
  font-weight: 760;
}

.manual-three-up {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 12px;
}

.manual-glossary-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
}

.manual-glossary-list div {
  border: 1px solid var(--line);
  border-radius: 15px;
  background: var(--surface);
  padding: 12px;
  display: grid;
  gap: 4px;
}

.manual-glossary-list strong {
  color: var(--brand-deep);
}

.manual-glossary-list span {
  color: var(--muted);
  line-height: 1.35;
}

@media (max-width: 900px) {
  .manual-three-up,
  .manual-glossary-list {
    grid-template-columns: 1fr;
  }
}


/* Milestone 9 corrective polish: manual mobile layout and stacked examples */
.manual-validate-examples {
  display: grid;
  grid-template-columns: 1fr;
  gap: 14px;
  align-content: start;
  overflow: visible;
}

.manual-validate-examples .manual-example-card {
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  padding: 12px;
  display: grid;
  justify-items: center;
  gap: 8px;
}

.manual-validate-examples .manual-board {
  width: min(100%, 240px);
}


/* Keep the Validate and hints manual page readable on desktop and mobile. */
#manual-validate.manual-page {
  grid-template-columns: 1fr;
  align-items: start;
}

#manual-validate .manual-page-copy {
  max-width: 82ch;
}

@media (min-width: 980px) {
  #manual-validate .manual-validate-examples {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

@media (max-height: 760px) and (min-width: 901px) {
  #manual-validate .manual-validate-examples .manual-board {
    width: min(100%, 200px);
  }
}

@media (max-width: 900px) {
  .user-manual {
    overflow: hidden;
  }

  .manual-shell {
    height: 100%;
    min-height: 0;
  }

  .manual-layout {
    min-height: 0;
    overflow: hidden;
  }

  .manual-main {
    display: block;
    overflow-y: auto;
    min-height: 0;
    padding-bottom: 12px;
  }

  .manual-page-status,
  .manual-page,
  .manual-page-nav {
    margin-bottom: 12px;
  }

  .manual-page {
    align-items: start;
  }

  .manual-visual {
    overflow: hidden;
  }
}

@media (max-width: 720px) {
  .manual-header {
    gap: 10px;
    padding: 12px;
  }

  .manual-header h2 {
    font-size: 1.35rem;
    line-height: 1.05;
  }

  .manual-header p {
    font-size: 0.9rem;
    line-height: 1.35;
  }

  .manual-toc {
    padding: 8px;
    gap: 6px;
    max-height: 58px;
  }

  .manual-toc button {
    padding: 8px 10px;
    font-size: 0.86rem;
  }

  .manual-page {
    padding: 12px;
    gap: 12px;
  }

  .manual-page-copy h3 {
    font-size: 1.28rem;
    line-height: 1.1;
  }

  .manual-page-copy p,
  .manual-visual-note {
    font-size: 0.92rem;
    line-height: 1.42;
  }

  .manual-visual {
    padding: 12px;
    border-radius: 16px;
  }

  .manual-board {
    width: min(100%, 280px);
  }

  .manual-real-example-pair .manual-board,
  .manual-validate-examples .manual-board {
    width: min(100%, 260px);
  }

  .manual-cell.sudoku-cell-slot {
    font-size: clamp(0.62rem, 2.7vw, 0.95rem);
  }

  .manual-page-nav {
    gap: 8px;
  }
}

/* Milestone 9 correction: mobile-only styled puzzle dropdown. */
.mobile-puzzle-picker {
  display: none;
  position: relative;
  width: 100%;
}

.mobile-puzzle-picker[hidden],
.mobile-puzzle-picker-menu[hidden] {
  display: none !important;
}

.mobile-puzzle-picker-button {
  width: 100%;
  min-height: 46px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--surface);
  color: var(--ink);
  font: inherit;
  font-weight: 800;
  padding: 0 12px 0 14px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  box-shadow: 0 12px 30px rgba(15, 23, 42, 0.05);
  text-align: left;
}

.mobile-puzzle-picker-button:focus-visible {
  outline: 3px solid rgba(37, 99, 235, 0.22);
  border-color: rgba(37, 99, 235, 0.44);
}

.mobile-puzzle-picker-label {
  min-width: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.mobile-puzzle-picker-chevron {
  flex: 0 0 auto;
  color: var(--muted);
  font-size: 0.9rem;
}

.mobile-puzzle-picker-menu {
  position: absolute;
  z-index: 35;
  top: calc(100% + 8px);
  left: 0;
  right: 0;
  max-height: min(60vh, 420px);
  overflow-y: auto;
  overscroll-behavior: contain;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--surface);
  box-shadow: 0 22px 55px rgba(15, 23, 42, 0.18);
  padding: 8px;
}

.mobile-puzzle-picker-heading {
  color: var(--brand-deep);
  font-weight: 950;
  font-size: 0.78rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: 10px 10px 6px;
}

.mobile-puzzle-picker-option {
  width: 100%;
  border: 0;
  border-radius: 12px;
  background: transparent;
  color: var(--ink);
  font: inherit;
  font-weight: 400;
  text-align: left;
  padding: 11px 10px 11px 26px;
  display: block;
}

.mobile-puzzle-picker-option:hover,
.mobile-puzzle-picker-option:focus-visible {
  background: var(--accent-soft);
  outline: none;
}

.mobile-puzzle-picker-option[aria-selected="true"] {
  background: rgba(37, 99, 235, 0.1);
  color: var(--brand-deep);
  font-weight: 500;
}

.mobile-puzzle-picker-option.is-placeholder {
  color: var(--muted);
  font-weight: 400;
}

@media (max-width: 900px) {
  .puzzle-select {
    display: none !important;
  }

  .mobile-puzzle-picker:not([hidden]) {
    display: block;
  }
}

@media (min-width: 901px) {
  .mobile-puzzle-picker {
    display: none !important;
  }
}


/* Milestone 9 correction: force polished mobile puzzle picker and prevent manual overflow. */
@media (max-width: 900px) {
  .loader-card .puzzle-select {
    display: none !important;
  }

  .loader-card .mobile-puzzle-picker:not([hidden]) {
    display: block !important;
  }

  .mobile-puzzle-picker-heading {
    font-weight: 950;
    color: var(--brand-deep);
  }

  .mobile-puzzle-picker-option {
    appearance: none;
    -webkit-appearance: none;
    font-weight: 400;
    padding-left: 26px;
  }
}

.scan-detected-frame {
  position: relative;
  display: inline-block;
  width: fit-content;
  max-width: 100%;
  margin: 12px 0;
  line-height: 0;
}

.scan-detected-frame .scan-detected-canvas {
  display: block;
  margin: 0;
  width: auto;
  max-width: 100%;
  height: auto;
}

.scan-detected-canvas {
  touch-action: none;
  cursor: crosshair;
  max-height: none;
  object-fit: fill;
}

.scan-detected-canvas.can-adjust-corner,
.scan-detected-canvas.is-adjusting {
  cursor: grab;
}

.scan-detected-canvas.is-adjusting {
  cursor: grabbing;
}

.scan-corner-handle {
  position: absolute;
  z-index: 2;
  width: 26px;
  height: 26px;
  padding: 0;
  border: 3px solid rgba(124, 58, 237, 1);
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.95);
  box-shadow: 0 0 0 3px rgba(124, 58, 237, 0.2);
  transform: translate(-50%, -50%);
  cursor: grab;
  touch-action: none;
}

.scan-corner-handle:hover,
.scan-corner-handle:focus-visible {
  outline: none;
  box-shadow: 0 0 0 5px rgba(124, 58, 237, 0.28);
}

.scan-corner-handle.is-adjusting {
  cursor: grabbing;
}

.scan-corner-handle[hidden] {
  display: none;
}