:root {
  --bg: #f6f3ee;
  --paper: #fffdfa;
  --ink: #151515;
  --muted: #66625c;
  --line: #d9d3ca;
  --line-strong: #1c1c1c;
  --accent: #2f5d50;
  --accent-soft: #e6eee9;
  --danger: #a1372b;
  --danger-soft: #f4dedb;
  --shadow: 0 22px 60px rgba(20, 20, 20, 0.08);
  --radius: 26px;
  color-scheme: light;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--bg);
  -webkit-text-size-adjust: 100%;
}

body {
  min-height: 100%;
  margin: 0;
  overflow-x: hidden;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    radial-gradient(circle at top left, rgba(47, 93, 80, 0.10), transparent 38%),
    linear-gradient(135deg, #f8f5ef 0%, #eee8de 100%);
  color: var(--ink);
}

button,
select {
  font: inherit;
}

button {
  min-height: 44px;
  border: 0;
  border-radius: 999px;
  padding: 0.75rem 1rem;
  background: var(--ink);
  color: #fff;
  cursor: pointer;
  touch-action: manipulation;
  transition: transform 160ms ease, box-shadow 160ms ease, background 160ms ease, border-color 160ms ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 28px rgba(0, 0, 0, 0.12);
}

button:active {
  transform: translateY(0);
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
}

button:focus-visible,
select:focus-visible,
.cell:focus-visible {
  outline: 3px solid rgba(47, 93, 80, 0.34);
  outline-offset: 3px;
}

.app-shell {
  width: min(1180px, 100%);
  margin: 0 auto;
  padding: 28px 16px 44px;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  margin-bottom: 24px;
}

.eyebrow {
  margin: 0 0 6px;
  color: var(--muted);
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

h1,
h2,
p {
  margin-top: 0;
}

h1 {
  margin-bottom: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: clamp(2.35rem, 7vw, 5.25rem);
  font-weight: 900;
  line-height: 0.92;
  letter-spacing: -0.075em;
}

h2 {
  margin-bottom: 12px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-size: clamp(1.55rem, 3vw, 2.18rem);
  font-weight: 850;
  letter-spacing: -0.055em;
}

.ghost-button {
  background: transparent;
  color: var(--ink);
  border: 1px solid rgba(21, 21, 21, 0.22);
}

.game-layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 24px;
  align-items: start;
}

.game-card,
.info-card {
  background: rgba(255, 253, 250, 0.82);
  border: 1px solid rgba(21, 21, 21, 0.08);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(12px);
}

.game-card {
  width: 100%;
  min-width: 0;
  padding: clamp(14px, 3vw, 28px);
}

.info-card {
  position: sticky;
  top: 22px;
  padding: 28px;
}

.info-card p {
  color: var(--muted);
  line-height: 1.62;
}

.toolbar {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 18px;
}

.field-label {
  display: grid;
  gap: 8px;
  color: var(--muted);
  font-size: 0.82rem;
  font-weight: 700;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

select {
  min-height: 44px;
  border: 1px solid rgba(21, 21, 21, 0.16);
  border-radius: 14px;
  background: #fff;
  color: var(--ink);
  padding: 0 42px 0 14px;
}

.stat-group {
  display: flex;
  gap: 10px;
}

.stat {
  min-width: 82px;
  padding: 10px 12px;
  border: 1px solid rgba(21, 21, 21, 0.08);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.68);
}

.stat span {
  display: block;
  margin-bottom: 3px;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
}

.stat strong {
  font-size: 1rem;
}

.board-wrap {
  display: grid;
  justify-items: center;
  min-width: 0;
}

.sudoku-board {
  width: min(100%, 612px);
  aspect-ratio: 1 / 1;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  border: 3px solid var(--line-strong);
  border-radius: 18px;
  overflow: hidden;
  background: var(--line-strong);
  box-shadow: inset 0 0 0 1px var(--line-strong);
}

.cell {
  position: relative;
  display: grid;
  place-items: center;
  min-width: 0;
  min-height: 0;
  border: 0;
  border-right: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
  border-radius: 0;
  background: var(--paper);
  color: var(--accent);
  font-weight: 750;
  font-size: clamp(1.1rem, 4.4vw, 2.25rem);
  line-height: 1;
  padding: 0;
  user-select: none;
}

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

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

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

.cell.fixed {
  color: var(--ink);
  background: #f0ebe3;
  font-weight: 850;
}

.cell.selected {
  background: var(--accent-soft);
}

.cell.peer {
  background: #f8f5ef;
}

.cell.same-number:not(.empty) {
  background: #eaf0eb;
}

.cell.error {
  background: var(--danger-soft);
  color: var(--danger);
}

.notes-grid {
  width: 82%;
  height: 82%;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  align-items: center;
  justify-items: center;
  color: rgba(47, 93, 80, 0.72);
  font-size: clamp(0.44rem, 1.5vw, 0.75rem);
  font-weight: 800;
  line-height: 1;
  pointer-events: none;
}

.controls {
  margin-top: 16px;
}

.number-pad {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 8px;
}

.number-pad button,
.action-row button {
  background: #fff;
  color: var(--ink);
  border: 1px solid rgba(21, 21, 21, 0.12);
  font-weight: 800;
}

.number-pad button.active,
#noteBtn.active {
  background: var(--ink);
  color: #fff;
}

#noteBtn.active {
  border-color: var(--ink);
}

.action-row {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-top: 12px;
}

#checkBtn,
#modalNewGame {
  background: var(--accent);
  color: #fff;
}

.rules-list {
  display: grid;
  gap: 10px;
  margin: 22px 0 0;
  padding-left: 18px;
  color: var(--muted);
  line-height: 1.5;
}

.message-box {
  min-height: 54px;
  margin-top: 14px;
  border-radius: 18px;
  background: #f2ede5;
  border: 1px solid rgba(21, 21, 21, 0.08);
  padding: 13px 15px;
  color: var(--ink);
  line-height: 1.38;
}

.modal-backdrop {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  padding: 24px;
  background: rgba(17, 17, 17, 0.42);
  z-index: 20;
}

.modal-backdrop[hidden] {
  display: none;
}

.modal {
  width: min(420px, 100%);
  border-radius: 30px;
  background: var(--paper);
  box-shadow: 0 28px 88px rgba(0, 0, 0, 0.22);
  padding: 32px;
  text-align: center;
}

.modal p:not(.eyebrow) {
  color: var(--muted);
  line-height: 1.55;
}


.result-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin: 20px 0 22px;
}

.result-stat {
  padding: 12px 10px;
  border: 1px solid rgba(21, 21, 21, 0.08);
  border-radius: 18px;
  background: #f7f2eb;
}

.result-stat span {
  display: block;
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 0.66rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.result-stat strong {
  font-size: 1.05rem;
}

.start-backdrop {
  background:
    radial-gradient(circle at top left, rgba(47, 93, 80, 0.18), transparent 34%),
    rgba(17, 17, 17, 0.36);
}

.start-modal {
  text-align: left;
}

.start-modal p:not(.eyebrow) {
  max-width: 34rem;
}

.start-actions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 10px;
  margin-top: 22px;
}

.start-actions button {
  border: 1px solid rgba(21, 21, 21, 0.12);
  background: #fff;
  color: var(--ink);
  font-weight: 850;
}

.start-actions button:first-child {
  grid-column: 1 / -1;
  background: var(--ink);
  color: #fff;
}

.start-actions button[hidden] {
  display: none;
}

.start-actions button:first-child[hidden] + button {
  grid-column: auto;
}

@media (prefers-reduced-motion: no-preference) {
  .modal {
    animation: modalIn 180ms ease-out both;
  }

  @keyframes modalIn {
    from {
      opacity: 0;
      transform: translateY(8px) scale(0.98);
    }
    to {
      opacity: 1;
      transform: translateY(0) scale(1);
    }
  }
}

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

  .info-card {
    position: static;
  }
}

@media (max-width: 640px) {
  .app-shell {
    padding: 12px max(10px, env(safe-area-inset-right)) 24px max(10px, env(safe-area-inset-left));
  }

  .site-header {
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
  }

  .eyebrow {
    margin-bottom: 3px;
    font-size: 0.62rem;
    letter-spacing: 0.13em;
  }

  h1 {
    font-size: clamp(2rem, 12vw, 3.35rem);
    letter-spacing: -0.055em;
  }

  .compact-top-action {
    min-height: 38px;
    padding: 0.56rem 0.72rem;
    font-size: 0.86rem;
  }

  .game-layout {
    gap: 14px;
  }

  .game-card {
    padding: 10px;
    border-radius: 20px;
  }

  .toolbar {
    display: grid;
    gap: 10px;
    margin-bottom: 10px;
  }

  .field-label {
    gap: 5px;
    width: 100%;
    font-size: 0.68rem;
    letter-spacing: 0.05em;
  }

  select {
    width: 100%;
    min-height: 40px;
    border-radius: 12px;
  }

  .stat-group {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 6px;
  }

  .stat {
    min-width: 0;
    padding: 7px 7px;
    border-radius: 14px;
  }

  .stat span {
    margin-bottom: 2px;
    font-size: 0.58rem;
  }

  .stat strong {
    font-size: 0.86rem;
  }

  .sudoku-board {
    width: min(100%, calc(100vw - 20px));
    border-width: 2px;
    border-radius: 13px;
  }

  .cell {
    border-right-width: 1px;
    border-bottom-width: 1px;
    font-size: clamp(1rem, 6.4vw, 1.48rem);
  }

  .cell:nth-child(3n) {
    border-right-width: 2px;
  }

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

  .cell:nth-child(n + 19):nth-child(-n + 27),
  .cell:nth-child(n + 46):nth-child(-n + 54) {
    border-bottom-width: 2px;
  }

  .notes-grid {
    width: 88%;
    height: 88%;
    font-size: clamp(0.4rem, 2.4vw, 0.62rem);
  }

  .message-box {
    min-height: 44px;
    margin-top: 9px;
    padding: 10px 11px;
    border-radius: 14px;
    font-size: 0.86rem;
  }

  .controls {
    margin-top: 10px;
  }

  .number-pad {
    grid-template-columns: repeat(3, 1fr);
    gap: 7px;
  }

  .number-pad button,
  .action-row button {
    min-height: 42px;
    padding: 0.45rem 0.3rem;
    border-radius: 14px;
    font-size: 1rem;
  }

  .action-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 7px;
    margin-top: 8px;
  }

  .info-card {
    padding: 18px;
    border-radius: 20px;
  }

  .info-card p,
  .rules-list {
    font-size: 0.92rem;
  }
}

@media (max-width: 380px) {
  .app-shell {
    padding-left: 8px;
    padding-right: 8px;
  }

  .game-card {
    padding: 8px;
  }

  .sudoku-board {
    width: min(100%, calc(100vw - 16px));
  }

  .number-pad button,
  .action-row button {
    min-height: 40px;
  }
}


/* v0.3.0 Inter typography, start screen and result polish */
.version-badge {
  position: fixed;
  right: max(10px, env(safe-area-inset-right));
  bottom: max(8px, env(safe-area-inset-bottom));
  z-index: 30;
  padding: 4px 8px;
  border: 1px solid rgba(21, 21, 21, 0.10);
  border-radius: 999px;
  background: rgba(255, 253, 250, 0.82);
  color: rgba(21, 21, 21, 0.52);
  box-shadow: 0 8px 24px rgba(20, 20, 20, 0.06);
  backdrop-filter: blur(10px);
  font-size: 0.66rem;
  font-weight: 800;
  letter-spacing: 0.04em;
  line-height: 1;
  pointer-events: none;
}

@media (max-width: 640px) {
  body {
    background:
      radial-gradient(circle at top left, rgba(47, 93, 80, 0.08), transparent 34%),
      linear-gradient(135deg, #f8f5ef 0%, #eee8de 100%);
  }

  button:hover {
    transform: none;
    box-shadow: none;
  }

  .app-shell {
    padding: 8px max(8px, env(safe-area-inset-right)) 18px max(8px, env(safe-area-inset-left));
  }

  .site-header {
    margin-bottom: 8px;
  }

  h1 {
    font-size: clamp(1.9rem, 10.5vw, 3rem);
    line-height: 0.95;
  }

  .compact-top-action {
    min-height: 34px;
    padding: 0.45rem 0.62rem;
    border-radius: 999px;
    font-size: 0.8rem;
  }

  .game-layout {
    gap: 0;
    max-width: 520px;
    margin: 0 auto;
  }

  .game-card {
    padding: 7px;
    border-radius: 18px;
    box-shadow: 0 14px 36px rgba(20, 20, 20, 0.07);
  }

  .toolbar {
    grid-template-columns: 1fr;
    gap: 7px;
    margin-bottom: 7px;
  }

  .field-label {
    grid-template-columns: auto minmax(0, 1fr);
    align-items: center;
    gap: 8px;
    font-size: 0.64rem;
    white-space: nowrap;
  }

  select {
    min-height: 34px;
    border-radius: 11px;
    padding-left: 11px;
    padding-right: 34px;
    font-size: 0.88rem;
  }

  .stat-group {
    gap: 5px;
  }

  .stat {
    padding: 5px 6px;
    border-radius: 12px;
  }

  .stat span {
    font-size: 0.54rem;
  }

  .stat strong {
    font-size: 0.82rem;
  }

  .sudoku-board {
    width: min(100%, calc(100svw - 30px), 94svmin);
    border-width: 2px;
    border-radius: 12px;
  }

  .cell {
    font-size: clamp(0.98rem, 5.8vw, 1.46rem);
  }

  .notes-grid {
    width: 90%;
    height: 90%;
    font-size: clamp(0.38rem, 2.15vw, 0.58rem);
  }

  .message-box {
    min-height: 36px;
    margin-top: 7px;
    padding: 8px 10px;
    border-radius: 12px;
    font-size: 0.81rem;
    line-height: 1.28;
  }

  .controls {
    margin-top: 7px;
  }

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

  .number-pad button:nth-child(6) {
    grid-column: 2;
  }

  .number-pad button,
  .action-row button {
    min-height: 38px;
    padding: 0.34rem 0.2rem;
    border-radius: 12px;
    font-size: 0.95rem;
  }

  .action-row {
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 5px;
    margin-top: 6px;
  }

  .action-row button {
    font-size: 0.82rem;
    font-weight: 850;
  }

  .info-card {
    display: none;
  }

  .version-badge {
    right: max(8px, env(safe-area-inset-right));
    bottom: max(6px, env(safe-area-inset-bottom));
    padding: 3px 6px;
    font-size: 0.58rem;
    opacity: 0.82;
  }
}

@media (max-width: 360px) {
  .app-shell {
    padding-left: 6px;
    padding-right: 6px;
  }

  .game-card {
    padding: 6px;
    border-radius: 16px;
  }

  .sudoku-board {
    width: min(100%, calc(100svw - 24px));
  }

  .cell {
    font-size: clamp(0.9rem, 5.6vw, 1.24rem);
  }

  .number-pad button,
  .action-row button {
    min-height: 36px;
  }
}

@media (max-width: 640px) and (max-height: 720px) {
  .site-header {
    margin-bottom: 6px;
  }

  .eyebrow {
    display: none;
  }

  h1 {
    font-size: clamp(1.72rem, 9vw, 2.55rem);
  }

  .message-box {
    min-height: 32px;
    padding-top: 7px;
    padding-bottom: 7px;
  }

  .number-pad button,
  .action-row button {
    min-height: 34px;
  }
}


@media (max-width: 640px) {
  .modal-backdrop {
    padding: 14px;
  }

  .modal {
    border-radius: 24px;
    padding: 24px;
  }

  .start-actions {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .start-actions button:first-child {
    grid-column: auto;
  }

  .result-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 8px;
    margin: 16px 0 18px;
  }

  .result-stat {
    border-radius: 14px;
    padding: 10px 8px;
  }
}