/* 浅色 / 深色主题变量 */
:root,
[data-theme='light'] {
  color-scheme: light;
  --bg: #f4f6f9;
  --surface: #ffffff;
  --text: #1a1d26;
  --muted: #6b7280;
  --border: #e2e8f0;
  --accent: #3b82f6;
  --accent-hover: #2563eb;
  --given: #111827;
  --user: #1d4ed8;
  --same: #dbeafe;
  --selected: #bfdbfe;
  --conflict: #fecaca;
  --conflict-text: #b91c1c;
  --thick: #334155;
  --shadow: 0 4px 24px rgba(15, 23, 42, 0.08);
}

[data-theme='dark'] {
  color-scheme: dark;
  --bg: #0f1419;
  --surface: #1a2332;
  --text: #e8eef7;
  --muted: #94a3b8;
  --border: #2d3a4f;
  --accent: #60a5fa;
  --accent-hover: #93c5fd;
  --given: #f1f5f9;
  --user: #93c5fd;
  --same: #1e3a5f;
  --selected: #2d4a6f;
  --conflict: #7f1d1d;
  --conflict-text: #fecaca;
  --thick: #cbd5e1;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.35);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, 'PingFang SC', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.5;
  -webkit-text-size-adjust: 100%;
  touch-action: manipulation;
}

.app {
  max-width: 480px;
  margin: 0 auto;
  padding: calc(1.25rem + env(safe-area-inset-top, 0px)) calc(1rem + env(safe-area-inset-right, 0px))
    calc(2rem + env(safe-area-inset-bottom, 0px)) calc(1rem + env(safe-area-inset-left, 0px));
}

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

.title {
  margin: 0;
  font-size: 1.5rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  justify-content: flex-end;
}

.btn {
  padding: 0.45rem 0.85rem;
  min-height: 2.75rem;
  font-size: 0.875rem;
  font-weight: 600;
  border-radius: 0.5rem;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

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

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

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

.btn-ghost {
  background: transparent;
}

.message {
  min-height: 1.5rem;
  margin: 0 0 0.75rem;
  font-size: 0.875rem;
  color: var(--muted);
}

.board-wrap {
  display: flex;
  justify-content: center;
  margin-bottom: 1.25rem;
}

/* 9×9 主棋盘 */
.board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  grid-template-rows: repeat(9, 1fr);
  gap: 0;
  width: min(100vw - 2rem, 400px);
  aspect-ratio: 1;
  background: var(--thick);
  padding: 2px;
  border-radius: 0.75rem;
  box-shadow: var(--shadow);
}

.cell {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(1rem, 4vw, 1.35rem);
  font-weight: 600;
  background: var(--surface);
  color: var(--user);
  cursor: pointer;
  user-select: none;
  outline: none;
  margin: 0;
  border: none;
  border-radius: 0;
  transition: background 0.12s, color 0.12s;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
}

.cell:focus-visible {
  z-index: 1;
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

/* 细线格 + 三宫一道粗线（右、下内阴影，不撑开布局） */
.cell {
  box-shadow: 0 0 0 0.5px var(--border) inset;
}

/* 宫内竖向分隔（第 3、6 列右侧） */
.board > .cell:nth-child(9n + 3),
.board > .cell:nth-child(9n + 6) {
  box-shadow:
    0 0 0 0.5px var(--border) inset,
    inset -2px 0 0 0 var(--thick);
}

/* 宫内横向分隔（第 3、6 行底边） */
.board > .cell:nth-child(n + 19):nth-child(-n + 27),
.board > .cell:nth-child(n + 46):nth-child(-n + 54) {
  box-shadow:
    0 0 0 0.5px var(--border) inset,
    inset 0 -2px 0 0 var(--thick);
}

/* 第二宫、第五宫下排与横粗线交汇处：双 :nth-child 与横行同特异性；竖线与其它宫竖边同为 2px */
.board > .cell:nth-child(n + 21):nth-child(-n + 21),
.board > .cell:nth-child(n + 24):nth-child(-n + 24),
.board > .cell:nth-child(n + 48):nth-child(-n + 48),
.board > .cell:nth-child(n + 51):nth-child(-n + 51) {
  box-shadow:
    0 0 0 0.5px var(--border) inset,
    inset -2px 0 0 0 var(--thick),
    inset 0 -2px 0 0 var(--thick);
}

.cell.given {
  color: var(--given);
  font-weight: 700;
  cursor: default;
}

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

.cell.same-digit {
  background: var(--same);
}

.cell.conflict {
  background: var(--conflict);
  color: var(--conflict-text);
}

.cell.wrong {
  text-decoration: line-through;
  opacity: 0.9;
}

/* 底部 1–9：三行 123 / 456 / 789 */
.palette {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.5rem;
  width: 100%;
}

.palette-row {
  display: flex;
  flex-wrap: nowrap;
  justify-content: center;
  align-items: center;
  gap: 0.5rem;
}

.palette-btn {
  width: 2.75rem;
  height: 2.75rem;
  min-width: 2.75rem;
  min-height: 2.75rem;
  border-radius: 0.5rem;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font-size: 1.1rem;
  font-weight: 700;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  cursor: pointer;
  transition: opacity 0.15s, background 0.15s;
}

.palette-btn:hover:not(:disabled) {
  border-color: var(--accent);
  color: var(--accent);
}

.palette-btn:disabled {
  opacity: 0.35;
  cursor: not-allowed;
}

/* 难度弹窗 */
.modal {
  border: none;
  border-radius: 1rem;
  padding: 0;
  background: var(--surface);
  color: var(--text);
  box-shadow: var(--shadow);
  max-width: 320px;
  width: calc(100% - 2rem);
}

.modal::backdrop {
  background: rgba(15, 23, 42, 0.45);
}

.modal-form {
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.modal-title {
  margin: 0 0 0.25rem;
  font-size: 1.125rem;
}

.difficulty-btns {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.btn-block {
  width: 100%;
}

/* 通关庆祝：高雅企鹅（几何剪影 + 华尔兹式轻盈摆动） */
.modal-victory {
  max-width: 340px;
}

.modal-victory::backdrop {
  background: rgba(15, 23, 42, 0.52);
  backdrop-filter: blur(6px);
}

[data-theme='dark'] .modal-victory::backdrop {
  background: rgba(0, 0, 0, 0.65);
}

.victory-form {
  align-items: center;
  text-align: center;
}

.victory-title {
  font-weight: 700;
  letter-spacing: 0.08em;
}

.victory-sub {
  margin: 0;
  font-size: 0.875rem;
  color: var(--muted);
}

.victory-dance-caption {
  margin: -0.15rem 0 0;
  font-size: 0.8125rem;
  font-weight: 500;
  letter-spacing: 0.12em;
  color: var(--muted);
  opacity: 0.9;
}

.penguin-stage {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 11rem;
  width: 100%;
  margin: 0.5rem 0;
  border-radius: 0.75rem;
  background: radial-gradient(
    ellipse 72% 58% at 50% 66%,
    color-mix(in srgb, var(--accent) 14%, transparent) 0%,
    transparent 72%
  );
}

.penguin {
  position: relative;
  width: 5.5rem;
  height: 8rem;
  animation: penguin-dance 2.45s cubic-bezier(0.45, 0.02, 0.28, 1) infinite;
  transform-origin: 50% 85%;
  filter: drop-shadow(0 0.35rem 0.5rem rgba(15, 23, 42, 0.12));
}

[data-theme='dark'] .penguin {
  filter: drop-shadow(0 0.4rem 0.65rem rgba(0, 0, 0, 0.45));
}

@keyframes penguin-dance {
  0%,
  100% {
    transform: translateY(0) rotate(-3deg);
  }
  18% {
    transform: translateY(-0.38rem) rotate(2.8deg);
  }
  36% {
    transform: translateY(-0.72rem) rotate(-2.2deg);
  }
  54% {
    transform: translateY(-0.48rem) rotate(3.2deg);
  }
  72% {
    transform: translateY(-0.22rem) rotate(-1.6deg);
  }
  88% {
    transform: translateY(-0.08rem) rotate(1.2deg);
  }
}

.penguin-torso {
  position: absolute;
  left: 50%;
  bottom: 1.15rem;
  width: 4.25rem;
  height: 5.5rem;
  margin-left: -2.125rem;
  background: linear-gradient(165deg, #334155 0%, #1e293b 45%, #0f172a 100%);
  border-radius: 48% 48% 42% 42% / 55% 55% 45% 45%;
  box-shadow: inset 0 -0.5rem 0.75rem rgba(0, 0, 0, 0.2);
}

.penguin-belly {
  position: absolute;
  left: 50%;
  bottom: 0.35rem;
  width: 2.6rem;
  height: 3.2rem;
  margin-left: -1.3rem;
  background: linear-gradient(180deg, #f8fafc 0%, #e2e8f0 100%);
  border-radius: 50% 50% 45% 45%;
  opacity: 0.97;
}

.penguin-face {
  position: absolute;
  top: 0.55rem;
  left: 0;
  right: 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.35rem;
  padding: 0 0.4rem;
}

.penguin-eye {
  width: 0.38rem;
  height: 0.5rem;
  background: #0f172a;
  border-radius: 50%;
  box-shadow: 0 0 0 1px #f1f5f9;
}

.penguin-beak {
  flex: 0 0 100%;
  width: 0;
  height: 0;
  margin: 0.1rem auto 0;
  border-left: 0.35rem solid transparent;
  border-right: 0.35rem solid transparent;
  border-top: 0.5rem solid #d97706;
  filter: drop-shadow(0 1px 1px rgba(0, 0, 0, 0.12));
}

.penguin-flipper {
  position: absolute;
  width: 1.1rem;
  height: 2.4rem;
  background: linear-gradient(90deg, #1e293b, #334155);
  border-radius: 45% 55% 60% 40%;
  top: 2.6rem;
}

.penguin-flipper-l {
  left: 0.15rem;
  transform-origin: 50% 0.25rem;
  animation: penguin-wing-l 1.18s cubic-bezier(0.42, 0.06, 0.32, 1) infinite alternate;
}

.penguin-flipper-r {
  right: 0.15rem;
  transform-origin: 50% 0.25rem;
  animation: penguin-wing-r 1.18s cubic-bezier(0.42, 0.06, 0.32, 1) infinite alternate;
  animation-delay: 0.22s;
}

@keyframes penguin-wing-l {
  from {
    transform: rotate(24deg) scaleY(1.03);
  }
  to {
    transform: rotate(-14deg) scaleY(0.97);
  }
}

@keyframes penguin-wing-r {
  from {
    transform: rotate(-24deg) scaleY(1.03);
  }
  to {
    transform: rotate(14deg) scaleY(0.97);
  }
}

.penguin-foot {
  position: absolute;
  bottom: 0.15rem;
  width: 0.85rem;
  height: 0.45rem;
  background: #d97706;
  border-radius: 40% 40% 50% 50%;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.15);
}

.penguin-foot-l {
  left: 1.35rem;
  animation: penguin-tap-l 2.45s cubic-bezier(0.45, 0.02, 0.28, 1) infinite;
}

.penguin-foot-r {
  right: 1.35rem;
  animation: penguin-tap-r 2.45s cubic-bezier(0.45, 0.02, 0.28, 1) infinite;
}

@keyframes penguin-tap-l {
  0%,
  100% {
    transform: translateY(0) scaleY(1);
  }
  22% {
    transform: translateY(-3px) scaleY(0.9);
  }
  44% {
    transform: translateY(-1px) scaleY(1);
  }
  66% {
    transform: translateY(-2.5px) scaleY(0.94);
  }
  82% {
    transform: translateY(0) scaleY(1);
  }
}

@keyframes penguin-tap-r {
  0%,
  100% {
    transform: translateY(-2px) scaleY(0.95);
  }
  22% {
    transform: translateY(0) scaleY(1);
  }
  44% {
    transform: translateY(-3px) scaleY(0.9);
  }
  66% {
    transform: translateY(-1px) scaleY(1);
  }
  82% {
    transform: translateY(-2.5px) scaleY(0.94);
  }
}

/* 窄屏：工具栏更易点按 */
@media (max-width: 380px) {
  .toolbar {
    width: 100%;
    justify-content: center;
  }

  .toolbar .btn {
    flex: 1 1 calc(50% - 0.25rem);
    min-width: 0;
    padding-left: 0.4rem;
    padding-right: 0.4rem;
    font-size: 0.8125rem;
  }
}

@media (prefers-reduced-motion: reduce) {
  .penguin,
  .penguin-flipper-l,
  .penguin-flipper-r,
  .penguin-foot-l,
  .penguin-foot-r {
    animation: none;
  }

  .modal-victory::backdrop {
    backdrop-filter: none;
  }
}