:root {
  --page-pad: 1rem;
  --bg-deep: #07131f;
  --bg-mid: #0d2434;
  --bg-soft: #16384b;
  --glow-cyan: rgba(141, 224, 230, 0.34);
  --glow-amber: rgba(244, 200, 115, 0.32);
  --glow-coral: rgba(255, 141, 115, 0.3);
  --panel-top: rgba(11, 28, 40, 0.78);
  --panel-bottom: rgba(8, 19, 31, 0.94);
  --line-soft: rgba(255, 255, 255, 0.09);
  --line-strong: rgba(255, 255, 255, 0.18);
  --text-primary: #eef6fb;
  --text-secondary: rgba(232, 241, 247, 0.75);
  --text-muted: rgba(212, 224, 232, 0.54);
  --accent-cyan: #8de0e6;
  --accent-amber: #f4c873;
  --accent-coral: #ff8d73;
  --accent-ink: #0d1724;
  --shadow-deep: 0 28px 80px rgba(0, 0, 0, 0.35);
  --shadow-soft: 0 18px 30px rgba(0, 0, 0, 0.2);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--page-pad);
  overflow: hidden;
  color: var(--text-primary);
  font-family: "Avenir Next", "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  background:
    radial-gradient(circle at 12% 14%, rgba(244, 200, 115, 0.24), transparent 28%),
    radial-gradient(circle at 84% 18%, rgba(141, 224, 230, 0.18), transparent 26%),
    radial-gradient(circle at 78% 82%, rgba(29, 105, 125, 0.32), transparent 28%),
    linear-gradient(135deg, var(--bg-deep) 0%, var(--bg-mid) 52%, var(--bg-soft) 100%);
}

body::before {
  content: "";
  position: fixed;
  inset: 0;
  background:
    linear-gradient(rgba(255, 255, 255, 0.02) 1px, transparent 1px),
    linear-gradient(90deg, rgba(255, 255, 255, 0.02) 1px, transparent 1px);
  background-size: 120px 120px;
  pointer-events: none;
  opacity: 0.5;
}

body::after {
  content: "";
  position: fixed;
  inset: 0;
  background:
    radial-gradient(circle at 50% 14%, rgba(255, 255, 255, 0.06), transparent 36%),
    radial-gradient(circle at 18% 82%, rgba(244, 200, 115, 0.08), transparent 24%),
    radial-gradient(circle at 88% 70%, rgba(141, 224, 230, 0.08), transparent 28%);
  mix-blend-mode: screen;
  opacity: 0.72;
  pointer-events: none;
}

.ambient {
  position: fixed;
  border-radius: 999px;
  filter: blur(18px);
  pointer-events: none;
  opacity: 0.7;
}

.ambient-one {
  width: 18rem;
  height: 18rem;
  top: 4%;
  left: 6%;
  background: linear-gradient(180deg, rgba(255, 215, 127, 0.38), rgba(255, 179, 91, 0.05));
  animation: drift-one 14s ease-in-out infinite alternate;
}

.ambient-two {
  width: 24rem;
  height: 24rem;
  right: -2rem;
  top: 12%;
  background: linear-gradient(180deg, rgba(108, 196, 204, 0.24), rgba(108, 196, 204, 0.02));
  animation: drift-two 18s ease-in-out infinite alternate;
}

.ambient-three {
  width: 20rem;
  height: 20rem;
  left: 48%;
  bottom: -6rem;
  background: linear-gradient(180deg, rgba(244, 200, 115, 0.14), rgba(255, 141, 115, 0.03));
  animation: drift-three 16s ease-in-out infinite alternate;
}

.game-shell {
  position: relative;
  z-index: 1;
  width: min(96vw, 1360px);
  height: min(calc(100svh - (var(--page-pad) * 2)), 920px);
  display: grid;
  grid-template-columns: minmax(320px, 410px) minmax(460px, 1fr);
  gap: clamp(1rem, 2vw, 1.5rem);
}

.panel {
  position: relative;
  overflow: hidden;
  border-radius: 2rem;
  border: 1px solid var(--line-strong);
  background: linear-gradient(180deg, var(--panel-top), var(--panel-bottom));
  box-shadow: var(--shadow-deep);
  backdrop-filter: blur(20px);
  transition: border-color 220ms ease, box-shadow 220ms ease, transform 220ms ease;
}

.panel::before {
  content: "";
  position: absolute;
  inset: 1px;
  border-radius: inherit;
  background:
    radial-gradient(circle at top left, rgba(255, 255, 255, 0.12), transparent 26%),
    radial-gradient(circle at 84% 18%, rgba(141, 224, 230, 0.06), transparent 24%),
    linear-gradient(180deg, rgba(255, 255, 255, 0.03), transparent 22%);
  pointer-events: none;
}

.panel::after {
  content: "";
  position: absolute;
  inset: 0;
  background: linear-gradient(160deg, rgba(255, 255, 255, 0.06), transparent 42%);
  pointer-events: none;
}

.panel:hover {
  border-color: rgba(255, 255, 255, 0.22);
  box-shadow:
    0 30px 90px rgba(0, 0, 0, 0.34),
    0 0 0 1px rgba(255, 255, 255, 0.03);
}

.intro-panel,
.board-panel {
  animation: float-in 700ms cubic-bezier(0.2, 0.8, 0.2, 1) both;
}

.board-panel {
  animation-delay: 120ms;
}

.intro-panel {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
  padding: clamp(1.25rem, 2vw, 1.75rem);
}

.intro-copy {
  display: grid;
  gap: 0.75rem;
}

.eyebrow,
.section-label,
.toggle-eyebrow,
.progress-label {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  color: var(--accent-amber);
  font-size: 0.78rem;
  letter-spacing: 0.2em;
  text-transform: uppercase;
}

.eyebrow::before,
.section-label::before,
.toggle-eyebrow::before {
  content: "";
  width: 0.7rem;
  height: 1px;
  background: currentColor;
  opacity: 0.75;
}

.brand-link {
  text-decoration: none;
}

.brand-link:hover {
  color: #f7d995;
}

h1,
h2 {
  margin: 0;
  font-family: "Baskerville", "Palatino Linotype", "Songti SC", "STSong", serif;
  font-weight: 700;
  letter-spacing: 0.03em;
}

h1 {
  font-size: clamp(2.8rem, 5vw, 4.4rem);
  line-height: 0.96;
  color: #f4fbff;
  background: linear-gradient(180deg, rgba(255, 255, 255, 0.99), rgba(223, 238, 245, 0.88));
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  filter: drop-shadow(0 14px 24px rgba(0, 0, 0, 0.18));
}

h2 {
  font-size: clamp(1.7rem, 2vw, 2.3rem);
  color: #f5fbff;
  text-shadow: 0 12px 24px rgba(0, 0, 0, 0.16);
}

.lead {
  margin: 0;
  color: var(--text-secondary);
  line-height: 1.72;
  font-size: 0.98rem;
}

.difficulty-block,
.tips-card {
  border-radius: 1.55rem;
  border: 1px solid var(--line-soft);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.05), rgba(255, 255, 255, 0.025)),
    rgba(255, 255, 255, 0.04);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.05);
}

.difficulty-block {
  padding: 1rem;
}

.section-head,
.board-topbar,
.keypad-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 1rem;
}

.section-caption,
#statusMessage,
.shortcut-list span,
.progress-card small {
  color: var(--text-muted);
}

.difficulty-switch {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.65rem;
  margin-top: 0.8rem;
}

.chip,
.action-button,
.keypad-button,
.toggle-card,
.cell,
.progress-card {
  position: relative;
  overflow: hidden;
  isolation: isolate;
  -webkit-tap-highlight-color: transparent;
}

.chip,
.action-button,
.keypad-button,
.toggle-card {
  border: none;
  cursor: pointer;
  transition:
    transform 180ms ease,
    box-shadow 180ms ease,
    background 180ms ease,
    color 180ms ease,
    border-color 180ms ease;
}

.chip::after,
.action-button::after,
.keypad-button::after,
.toggle-card::after {
  content: "";
  position: absolute;
  inset: -10%;
  background: linear-gradient(115deg, transparent 24%, rgba(255, 255, 255, 0.2) 50%, transparent 76%);
  opacity: 0;
  transform: translateX(-46%) rotate(14deg);
  transition: opacity 220ms ease, transform 340ms ease;
  pointer-events: none;
}

.chip {
  padding: 0.9rem 0.75rem;
  border-radius: 1rem;
  color: var(--text-secondary);
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid transparent;
  font-weight: 700;
  letter-spacing: 0.03em;
}

.chip:hover,
.chip.is-active {
  color: var(--accent-ink);
  background: linear-gradient(135deg, #f5d794, #9ce9ec);
  box-shadow: 0 12px 22px rgba(152, 217, 224, 0.22);
}

.chip:hover::after,
.chip.is-active::after,
.action-button:hover::after,
.keypad-button:hover::after,
.toggle-card:hover::after,
.toggle-card.active::after {
  opacity: 0.9;
  transform: translateX(42%) rotate(14deg);
}

.chip:disabled,
.action-button:disabled,
.keypad-button:disabled,
.toggle-card:disabled {
  cursor: wait;
  opacity: 0.65;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.8rem;
}

.stat-card {
  position: relative;
  overflow: hidden;
  display: grid;
  gap: 0.3rem;
  padding: 1rem;
  border-radius: 1.35rem;
  border: 1px solid var(--line-soft);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.06), rgba(255, 255, 255, 0.02)),
    rgba(255, 255, 255, 0.02);
  box-shadow: var(--shadow-soft);
  transition: transform 220ms ease, border-color 220ms ease, box-shadow 220ms ease;
}

.stat-card::before,
.difficulty-block::before,
.tips-card::before,
.progress-card::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at top right, rgba(255, 255, 255, 0.08), transparent 34%);
  pointer-events: none;
}

.stat-card:hover {
  transform: translateY(-2px);
  border-color: rgba(255, 255, 255, 0.16);
  box-shadow: 0 20px 34px rgba(0, 0, 0, 0.22);
}

.stat-label,
.stat-note {
  color: var(--text-muted);
}

.stat-value,
.progress-number {
  font-size: clamp(1.5rem, 2vw, 2rem);
  line-height: 1;
  font-weight: 800;
  font-variant-numeric: tabular-nums;
}

.action-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.75rem;
}

.action-button {
  min-height: 3.2rem;
  padding: 0.9rem 1rem;
  border-radius: 1.15rem;
  font-size: 0.98rem;
  font-weight: 800;
  color: var(--text-primary);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03)),
    rgba(255, 255, 255, 0.05);
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.04);
}

.action-button.primary {
  color: var(--accent-ink);
  background: linear-gradient(135deg, #f3cb82, #9ee6ea);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.3),
    0 12px 24px rgba(157, 230, 234, 0.18);
}

.action-button:hover:not(:disabled),
.toggle-card:hover:not(:disabled),
.keypad-button:hover:not(:disabled) {
  transform: translateY(-2px) scale(1.01);
  box-shadow: 0 12px 22px rgba(0, 0, 0, 0.22);
}

.chip:active:not(:disabled),
.action-button:active:not(:disabled),
.keypad-button:active:not(:disabled),
.toggle-card:active:not(:disabled) {
  transform: translateY(1px) scale(0.985);
}

.tips-card {
  display: grid;
  gap: 1rem;
  padding: 1rem;
}

.toggle-card {
  display: grid;
  justify-items: start;
  gap: 0.28rem;
  width: 100%;
  padding: 1rem 1.1rem;
  border-radius: 1.25rem;
  background: linear-gradient(135deg, rgba(244, 200, 115, 0.12), rgba(141, 224, 230, 0.1));
  color: var(--text-primary);
  text-align: left;
}

.toggle-card strong {
  font-size: 1.3rem;
}

.toggle-card.active {
  box-shadow: 0 12px 26px rgba(141, 224, 230, 0.18);
  background: linear-gradient(135deg, rgba(141, 224, 230, 0.24), rgba(244, 200, 115, 0.12));
}

.shortcut-list {
  display: grid;
  gap: 0.65rem;
}

.shortcut-list p {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin: 0;
  font-size: 0.92rem;
}

.shortcut-list strong {
  color: var(--text-secondary);
  font-weight: 700;
  text-align: right;
}

.board-panel {
  display: grid;
  grid-template-rows: auto minmax(0, 1fr) auto;
  gap: 1rem;
  padding: clamp(1rem, 2vw, 1.35rem);
}

.board-copy {
  display: grid;
  gap: 0.4rem;
  min-width: 0;
}

.board-copy p {
  margin: 0;
  font-size: 0.95rem;
}

.progress-card {
  min-width: 12.5rem;
  padding: 1rem 1.15rem;
  border-radius: 1.35rem;
  border: 1px solid var(--line-soft);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.07), rgba(255, 255, 255, 0.03)),
    rgba(255, 255, 255, 0.05);
  box-shadow: var(--shadow-soft);
  text-align: right;
  transition: box-shadow 220ms ease, border-color 220ms ease;
}

.board-frame {
  display: grid;
  place-items: start center;
  min-height: 0;
}

.board {
  position: relative;
  overflow: hidden;
  width: min(100%, 62vh, 620px);
  aspect-ratio: 1;
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 0;
  padding: 0.75rem;
  border-radius: 2rem;
  border: 1px solid rgba(255, 255, 255, 0.06);
  background:
    linear-gradient(160deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.02)),
    rgba(5, 14, 23, 0.8);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.08),
    0 22px 40px rgba(0, 0, 0, 0.25);
}

.board::before {
  content: "";
  position: absolute;
  inset: 8%;
  border-radius: 1.8rem;
  background:
    radial-gradient(circle at 50% 10%, rgba(141, 224, 230, 0.12), transparent 42%),
    radial-gradient(circle at 50% 100%, rgba(244, 200, 115, 0.08), transparent 34%);
  filter: blur(16px);
  opacity: 0.9;
  pointer-events: none;
}

.board > * {
  position: relative;
  z-index: 1;
}

.cell {
  position: relative;
  display: grid;
  place-items: center;
  padding: 0;
  border-style: solid;
  border-color: rgba(229, 240, 247, 0.12);
  background: rgba(255, 255, 255, 0.03);
  color: var(--text-primary);
  font: inherit;
  user-select: none;
  aspect-ratio: 1;
  transition:
    transform 180ms ease,
    background 180ms ease,
    box-shadow 180ms ease,
    border-color 180ms ease;
}

.cell::before {
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.08), transparent 62%);
  opacity: 0;
  transition: opacity 180ms ease;
  pointer-events: none;
}

.cell:first-child {
  border-top-left-radius: 1.2rem;
}

.cell:nth-child(9) {
  border-top-right-radius: 1.2rem;
}

.cell:nth-child(73) {
  border-bottom-left-radius: 1.2rem;
}

.cell:nth-child(81) {
  border-bottom-right-radius: 1.2rem;
}

.cell.editable {
  cursor: pointer;
}

.cell.editable:hover::before {
  opacity: 1;
}

.cell.editable:hover {
  background: rgba(255, 255, 255, 0.05);
  border-color: rgba(255, 255, 255, 0.2);
  z-index: 1;
}

.cell.fixed .cell-value {
  color: rgba(246, 251, 255, 0.96);
}

.cell.editable .cell-value {
  color: var(--accent-cyan);
}

.cell.related {
  background: rgba(255, 255, 255, 0.065);
}

.cell.same-value {
  background:
    linear-gradient(180deg, rgba(244, 200, 115, 0.2), rgba(244, 200, 115, 0.08)),
    rgba(255, 255, 255, 0.03);
  box-shadow: inset 0 0 0 1px rgba(244, 200, 115, 0.22);
}

.cell.selected {
  background:
    linear-gradient(180deg, rgba(141, 224, 230, 0.26), rgba(141, 224, 230, 0.08)),
    rgba(255, 255, 255, 0.04);
  transform: scale(1.03);
  box-shadow:
    inset 0 0 0 1px rgba(141, 224, 230, 0.55),
    0 0 24px rgba(141, 224, 230, 0.16);
  z-index: 2;
}

.cell.error {
  background:
    linear-gradient(180deg, rgba(255, 141, 115, 0.26), rgba(255, 141, 115, 0.08)),
    rgba(255, 255, 255, 0.04);
  box-shadow: inset 0 0 0 1px rgba(255, 141, 115, 0.42);
  animation: shake 380ms ease;
}

.cell.success {
  background:
    linear-gradient(180deg, rgba(244, 200, 115, 0.24), rgba(141, 224, 230, 0.08)),
    rgba(255, 255, 255, 0.04);
  box-shadow:
    inset 0 0 0 1px rgba(244, 200, 115, 0.44),
    0 0 22px rgba(141, 224, 230, 0.12);
  animation: pulse 450ms ease;
}

.cell-value {
  font-size: clamp(1.35rem, 2.4vw, 2rem);
  font-weight: 800;
  line-height: 1;
  text-shadow: 0 10px 18px rgba(0, 0, 0, 0.24);
  transition: transform 180ms ease, text-shadow 180ms ease;
}

.cell.selected .cell-value,
.cell.success .cell-value {
  transform: scale(1.08);
  text-shadow: 0 14px 24px rgba(0, 0, 0, 0.28);
}

.notes-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.1rem;
  width: 84%;
  height: 84%;
  align-content: center;
  justify-items: center;
  font-size: clamp(0.46rem, 0.85vw, 0.72rem);
  color: rgba(229, 240, 247, 0.65);
  font-weight: 700;
  text-shadow: 0 4px 10px rgba(0, 0, 0, 0.16);
}

.notes-grid span {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 0.85em;
}

.keypad-shell {
  display: grid;
  gap: 0.75rem;
}

.keypad {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 0.75rem;
}

.keypad-button {
  display: grid;
  gap: 0.25rem;
  min-height: 4rem;
  padding: 0.8rem 0.5rem;
  border-radius: 1.15rem;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03)),
    rgba(255, 255, 255, 0.03);
  color: var(--text-primary);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.06),
    0 10px 18px rgba(0, 0, 0, 0.12);
}

.keypad-button strong {
  font-size: 1.45rem;
  line-height: 1;
}

.keypad-button small {
  color: var(--text-muted);
}

.keypad-button.erase {
  background: linear-gradient(135deg, rgba(255, 141, 115, 0.2), rgba(255, 255, 255, 0.05));
}

.keypad-button.is-active {
  color: var(--accent-ink);
  background: linear-gradient(135deg, #f3cb82, #9de6ea);
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.25),
    0 16px 28px rgba(157, 230, 234, 0.16);
}

.toggle-card.active {
  box-shadow:
    0 18px 30px rgba(141, 224, 230, 0.16),
    inset 0 1px 0 rgba(255, 255, 255, 0.06);
}

body.note-mode .board {
  box-shadow:
    inset 0 1px 0 rgba(255, 255, 255, 0.08),
    0 22px 40px rgba(0, 0, 0, 0.25),
    0 0 0 1px rgba(244, 200, 115, 0.12),
    0 0 32px rgba(244, 200, 115, 0.08);
}

body.is-busy .board,
body.is-busy .panel {
  cursor: wait;
}

@keyframes float-in {
  from {
    opacity: 0;
    transform: translateY(18px) scale(0.985);
  }

  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes shake {
  20% {
    transform: translateX(-3px);
  }

  45% {
    transform: translateX(3px);
  }

  70% {
    transform: translateX(-2px);
  }

  100% {
    transform: translateX(0);
  }
}

@keyframes pulse {
  50% {
    transform: scale(1.04);
  }

  100% {
    transform: scale(1);
  }
}

.tap-wave {
  position: absolute;
  width: 0.85rem;
  aspect-ratio: 1;
  left: 0;
  top: 0;
  border-radius: 999px;
  transform: translate(-50%, -50%) scale(0.25);
  pointer-events: none;
  opacity: 0;
  mix-blend-mode: screen;
  animation: tap-wave 560ms cubic-bezier(0.16, 0.84, 0.28, 1) forwards;
}

.tap-wave.cyan {
  background: radial-gradient(circle, rgba(141, 224, 230, 0.62), rgba(141, 224, 230, 0.12) 48%, transparent 74%);
}

.tap-wave.amber {
  background: radial-gradient(circle, rgba(244, 200, 115, 0.62), rgba(244, 200, 115, 0.12) 48%, transparent 74%);
}

.tap-wave.coral {
  background: radial-gradient(circle, rgba(255, 141, 115, 0.62), rgba(255, 141, 115, 0.12) 48%, transparent 74%);
}

.burst {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 3;
}

.burst.success,
.burst.cyan {
  color: #8de0e6;
}

.burst.amber {
  color: #f4c873;
}

.burst.coral {
  color: #ff8d73;
}

.burst-particle {
  position: absolute;
  left: 50%;
  top: 50%;
  width: 0.34rem;
  height: 0.34rem;
  border-radius: 999px;
  background: currentColor;
  box-shadow: 0 0 14px currentColor;
  opacity: 0;
  transform: translate(-50%, -50%) scale(0.2);
  animation: burst-particle 620ms cubic-bezier(0.2, 0.8, 0.2, 1) forwards;
}

.pulse-cyan {
  animation: surface-cyan 520ms ease;
}

.pulse-amber {
  animation: surface-amber 520ms ease;
}

.pulse-coral {
  animation: surface-coral 520ms ease;
}

@keyframes tap-wave {
  0% {
    opacity: 0.72;
    transform: translate(-50%, -50%) scale(0.25);
  }

  100% {
    opacity: 0;
    transform: translate(-50%, -50%) scale(18);
  }
}

@keyframes burst-particle {
  0% {
    opacity: 0;
    transform: translate(-50%, -50%) scale(0.25);
  }

  18% {
    opacity: 1;
  }

  100% {
    opacity: 0;
    transform: translate(calc(-50% + var(--dx)), calc(-50% + var(--dy))) scale(0.15);
  }
}

@keyframes surface-cyan {
  0%,
  100% {
    box-shadow: inherit;
  }

  50% {
    box-shadow:
      0 0 0 1px rgba(141, 224, 230, 0.12),
      0 0 34px rgba(141, 224, 230, 0.2);
  }
}

@keyframes surface-amber {
  0%,
  100% {
    box-shadow: inherit;
  }

  50% {
    box-shadow:
      0 0 0 1px rgba(244, 200, 115, 0.12),
      0 0 34px rgba(244, 200, 115, 0.18);
  }
}

@keyframes surface-coral {
  0%,
  100% {
    box-shadow: inherit;
  }

  50% {
    box-shadow:
      0 0 0 1px rgba(255, 141, 115, 0.12),
      0 0 30px rgba(255, 141, 115, 0.16);
  }
}

@keyframes drift-one {
  from {
    transform: translate3d(0, 0, 0) scale(1);
  }

  to {
    transform: translate3d(1.5rem, 1rem, 0) scale(1.08);
  }
}

@keyframes drift-two {
  from {
    transform: translate3d(0, 0, 0) scale(1);
  }

  to {
    transform: translate3d(-1.3rem, 1.4rem, 0) scale(1.06);
  }
}

@keyframes drift-three {
  from {
    transform: translate3d(0, 0, 0) scale(1);
  }

  to {
    transform: translate3d(1rem, -1rem, 0) scale(1.05);
  }
}

@media (max-width: 1180px) {
  body {
    overflow: auto;
    align-items: flex-start;
  }

  .game-shell {
    width: min(95vw, 860px);
    height: auto;
    min-height: calc(100svh - 2rem);
    grid-template-columns: 1fr;
  }

  .board {
    width: min(100%, 74vw, 620px);
  }
}

@media (max-width: 760px) {
  body {
    --page-pad: 0.75rem;
  }

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

  .chip:last-child {
    grid-column: span 2;
  }

  .board-topbar,
  .shortcut-list p {
    flex-direction: column;
    align-items: flex-start;
    text-align: left;
  }

  .progress-card {
    width: 100%;
    min-width: 0;
    text-align: left;
  }

  .board {
    width: min(100%, 84vw, 520px);
    padding: 0.55rem;
  }

  .keypad-button.erase {
    grid-column: span 2;
  }
}

@media (max-height: 980px) and (min-width: 1181px) {
  :root {
    --page-pad: 0.7rem;
  }

  .game-shell {
    gap: 0.9rem;
  }

  .intro-panel,
  .board-panel {
    padding: 0.95rem;
  }

  .intro-panel {
    gap: 0.82rem;
  }

  .intro-copy {
    gap: 0.55rem;
  }

  h1 {
    font-size: clamp(2.3rem, 3.7vw, 3.65rem);
  }

  .lead {
    font-size: 0.91rem;
    line-height: 1.48;
  }

  .difficulty-block,
  .tips-card {
    border-radius: 1.35rem;
  }

  .difficulty-block,
  .tips-card,
  .stat-card {
    padding: 0.82rem;
  }

  .difficulty-switch {
    gap: 0.55rem;
    margin-top: 0.65rem;
  }

  .chip {
    padding: 0.78rem 0.65rem;
  }

  .stats-grid,
  .action-grid {
    gap: 0.55rem;
  }

  .stat-value,
  .progress-number {
    font-size: clamp(1.35rem, 1.8vw, 1.78rem);
  }

  .stat-note,
  .shortcut-list p,
  .board-copy p,
  .progress-card small,
  .keypad-button small {
    font-size: 0.84rem;
  }

  .action-button {
    min-height: 2.8rem;
    padding: 0.76rem 0.9rem;
  }

  .toggle-card {
    padding: 0.82rem 0.92rem;
  }

  .toggle-card strong {
    font-size: 1.15rem;
  }

  .shortcut-list {
    gap: 0.45rem;
  }

  .progress-card {
    min-width: 11rem;
    padding: 0.82rem 0.95rem;
  }

  .board-panel {
    gap: 0.72rem;
  }

  .board {
    width: min(100%, 54vh, 548px);
    padding: 0.62rem;
  }

  .keypad-shell {
    gap: 0.5rem;
  }

  .keypad,
  .keypad-head {
    gap: 0.6rem;
  }

  .keypad-button {
    min-height: 3.35rem;
    padding: 0.66rem 0.42rem;
  }
}

@media (max-height: 920px) and (min-width: 1181px) {
  .game-shell {
    grid-template-columns: minmax(300px, 392px) minmax(430px, 1fr);
  }

  .intro-panel,
  .board-panel {
    padding: 0.9rem;
  }

  .intro-panel {
    gap: 0.72rem;
  }

  .board-panel {
    gap: 0.64rem;
  }

  h1 {
    font-size: clamp(2.18rem, 3.4vw, 3.35rem);
  }

  .lead {
    line-height: 1.42;
    font-size: 0.88rem;
  }

  .stats-grid,
  .action-grid {
    gap: 0.5rem;
  }

  .stat-card {
    padding: 0.75rem;
  }

  .action-button {
    min-height: 2.65rem;
    font-size: 0.94rem;
  }

  .progress-card {
    min-width: 10.5rem;
    padding: 0.76rem 0.9rem;
  }

  .board {
    width: min(100%, 51vh, 520px);
    padding: 0.56rem;
  }

  .keypad-shell {
    gap: 0.42rem;
  }

  .keypad-button {
    min-height: 3.12rem;
    padding: 0.58rem 0.38rem;
  }

  .toggle-card {
    padding: 0.76rem 0.84rem;
  }

  .toggle-card strong {
    font-size: 1.05rem;
  }

  .shortcut-list {
    gap: 0.36rem;
  }

  .shortcut-list p,
  .stat-note {
    font-size: 0.8rem;
  }
}

@media (max-height: 820px) and (min-width: 1181px) {
  .game-shell {
    grid-template-columns: minmax(300px, 390px) minmax(430px, 1fr);
  }

  .intro-panel,
  .board-panel {
    padding: 1rem;
  }

  .lead {
    line-height: 1.55;
    font-size: 0.92rem;
  }

  .board-panel {
    gap: 0.72rem;
  }

  .board {
    width: min(100%, 52vh, 520px);
    padding: 0.58rem;
  }

  .action-button {
    min-height: 2.9rem;
  }

  .keypad-button {
    min-height: 3.4rem;
  }
}