.sudoku-app .subtitle {
  max-width: 28rem;
  margin-left: auto;
  margin-right: auto;
}

.sudoku-controls {
  margin-bottom: 1rem;
}

.sudoku-control-row {
  align-items: flex-start;
}

.sudoku-diff .difficulty-legend {
  margin-bottom: 0.35rem;
}

.sudoku-status {
  margin: 0.65rem 0 0;
  min-height: 1.35rem;
}

.sudoku-main {
  justify-content: center;
}

.sudoku-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1.15rem;
}

.sudoku-grid {
  --s-cell: min(10vmin, 44px);
  display: grid;
  grid-template-columns: repeat(9, var(--s-cell));
  grid-template-rows: repeat(9, var(--s-cell));
  width: calc(9 * var(--s-cell));
  gap: 0;
  padding: 3px;
  border-radius: calc(var(--radius) + 2px);
  background: linear-gradient(145deg, #1e3a5f 0%, #0f172a 50%, #172554 100%);
  box-shadow:
    0 0 0 2px rgba(56, 189, 248, 0.25),
    0 16px 48px rgba(0, 0, 0, 0.5),
    inset 0 1px 0 rgba(255, 255, 255, 0.08);
}

.sudoku-cell {
  margin: 0;
  padding: 0;
  width: var(--s-cell);
  height: var(--s-cell);
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(15, 23, 42, 0.92);
  color: var(--text);
  font-size: clamp(0.95rem, 3.5vmin, 1.2rem);
  font-weight: 600;
  font-variant-numeric: tabular-nums;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.12s ease, box-shadow 0.12s ease;
}

.sudoku-cell:nth-child(9n + 3),
.sudoku-cell:nth-child(9n + 6) {
  border-right: 2px solid rgba(56, 189, 248, 0.55);
}

.sudoku-cell:nth-child(n + 19):nth-child(-n + 27),
.sudoku-cell:nth-child(n + 46):nth-child(-n + 54) {
  border-bottom: 2px solid rgba(56, 189, 248, 0.55);
}

.sudoku-cell.given {
  color: #e0f2fe;
  background: rgba(30, 58, 138, 0.55);
  font-weight: 700;
  cursor: default;
}

.sudoku-cell.selected {
  background: rgba(14, 165, 233, 0.28);
  box-shadow: inset 0 0 0 2px rgba(56, 189, 248, 0.7);
  z-index: 1;
}

.sudoku-cell.conflict {
  background: rgba(248, 113, 113, 0.22);
  color: #fecaca;
}

.sudoku-cell.given.conflict {
  background: rgba(185, 28, 28, 0.45);
}

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

.sudoku-cell.win-pulse {
  animation: sudokuWin 0.6s ease;
}

@keyframes sudokuWin {
  0%,
  100% {
    box-shadow: inset 0 0 0 0 transparent;
  }
  50% {
    box-shadow: inset 0 0 12px rgba(52, 211, 153, 0.5);
  }
}

.sudoku-pad {
  width: 100%;
  max-width: calc(9 * var(--s-cell, 44px) + 6px);
}

.sudoku-pad-row {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 0.3rem;
  margin-bottom: 0.5rem;
}

.pad-btn {
  font: inherit;
  font-weight: 600;
  font-size: 0.95rem;
  padding: 0.4rem 0;
  border-radius: 6px;
  border: 1px solid rgba(100, 140, 200, 0.35);
  background: rgba(30, 41, 59, 0.9);
  color: var(--text);
  cursor: pointer;
  transition: background 0.12s ease, border-color 0.12s ease;
}

.pad-btn:hover {
  background: rgba(51, 65, 85, 0.95);
  border-color: rgba(56, 189, 248, 0.45);
}

.pad-btn:active {
  transform: scale(0.97);
}

.pad-erase {
  width: 100%;
}

.sudoku-won .sudoku-cell {
  cursor: default;
}

@media (max-width: 480px) {
  .sudoku-grid {
    --s-cell: min(9.2vmin, 38px);
  }

  .sudoku-pad-row {
    gap: 0.2rem;
  }

  .pad-btn {
    font-size: 0.85rem;
    padding: 0.35rem 0;
  }
}