.sudoku-page {
  padding: 24px 0 40px;
}

.breadcrumbs {
  margin: 16px 0 12px;
  font: 600 13px/1.4 Nunito, system-ui, sans-serif;
  color: #475569;
}

.breadcrumbs ol {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  padding: 0;
  margin: 0;
}

.breadcrumbs li::after {
  content: "›";
  margin-left: 6px;
  color: #94a3b8;
}

.breadcrumbs li:last-child::after {
  content: "";
}

.breadcrumbs a {
  color: #2563eb;
  text-decoration: none;
}

.sudoku-hero {
  text-align: left;
  padding: 12px 0 18px;
}

.sudoku-hero h1 {
  font: 700 32px/1.2 Poppins, sans-serif;
  margin: 0 0 8px;
  color: #0f172a;
}

.sudoku-hero p {
  font: 400 17px/1.65 Nunito, system-ui, sans-serif;
  color: #475569;
  max-width: 820px;
  margin: 0;
}

.ad-slot {
  margin: 18px 0;
  padding: 14px;
  border: 1px dashed #cbd5e1;
  border-radius: 12px;
  background: #f8fafc;
  color: #64748b;
  font: 700 12px/1 Poppins, sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  text-align: center;
}

.sudoku-layout {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
  align-items: start;
}

.sudoku-board-wrap {
  background: #f8fafc;
  border: 1px solid #e2e8f0;
  border-radius: 16px;
  padding: 16px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
}

.sudoku-status {
  min-height: 24px;
  font: 700 14px/1.4 Poppins, sans-serif;
  color: #0f172a;
  margin-bottom: 10px;
}

.sudoku-board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  gap: 0;
  border: 2px solid #0f172a;
  border-radius: 12px;
  overflow: hidden;
  background: #fff;
  aspect-ratio: 1 / 1;
}

.sudoku-cell {
  position: relative;
  border: 1px solid #e2e8f0;
  background: #ffffff;
  font: 700 18px/1 Poppins, sans-serif;
  color: #0f172a;
  display: flex;
  align-items: center;
  justify-content: center;
  aspect-ratio: 1 / 1;
  cursor: pointer;
  padding: 0;
}

.sudoku-cell:focus-visible {
  outline: 3px solid #f97316;
  outline-offset: -2px;
  z-index: 1;
}

.sudoku-cell.given {
  background: #f1f5f9;
  color: #0f172a;
  font-weight: 700;
}

.sudoku-cell.selected {
  background: #fff7ed;
  box-shadow: inset 0 0 0 2px rgba(249, 115, 22, 0.6);
}

.sudoku-cell.related {
  background: #f8fafc;
}

.sudoku-cell.same-number {
  background: #ede9fe;
}

.sudoku-cell.conflict,
.sudoku-cell.incorrect {
  background: #fee2e2;
  box-shadow: inset 0 0 0 2px rgba(239, 68, 68, 0.7);
}

.sudoku-cell.conflict::after,
.sudoku-cell.incorrect::after {
  content: "!";
  position: absolute;
  top: 3px;
  right: 4px;
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: #ef4444;
  color: #fff;
  font: 700 10px/14px Poppins, sans-serif;
  text-align: center;
}

.sudoku-cell[data-col="2"],
.sudoku-cell[data-col="5"] {
  border-right: 2px solid #0f172a;
}

.sudoku-cell[data-row="2"],
.sudoku-cell[data-row="5"] {
  border-bottom: 2px solid #0f172a;
}

.cell-value {
  z-index: 1;
}

.cell-notes {
  position: absolute;
  inset: 3px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  font: 600 9px/1 Nunito, sans-serif;
  color: #64748b;
  text-align: center;
  align-content: center;
  justify-items: center;
}

.cell-notes span {
  opacity: 0;
}

.cell-notes span.active {
  opacity: 1;
}

.sudoku-keypad {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 8px;
  margin-top: 16px;
}

.sudoku-keypad .key {
  border: 1px solid #cbd5e1;
  background: #fff;
  border-radius: 10px;
  padding: 10px 0;
  font: 700 16px/1 Poppins, sans-serif;
  color: #0f172a;
  cursor: pointer;
}

.sudoku-keypad .key.erase {
  grid-column: span 2;
  background: #0f172a;
  color: #fff;
}

.sudoku-controls {
  background: #ffffff;
  border: 1px solid #e2e8f0;
  border-radius: 16px;
  padding: 18px;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.06);
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: 16px;
}

.control-group label {
  font: 700 12px/1 Poppins, sans-serif;
  color: #475569;
  text-transform: uppercase;
  letter-spacing: 0.6px;
}

.control-group select {
  border: 1px solid #cbd5e1;
  border-radius: 10px;
  padding: 10px 12px;
  font: 600 14px/1 Nunito, system-ui, sans-serif;
  background: #f8fafc;
}

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

.control-buttons button {
  border: 1px solid #cbd5e1;
  background: #0f172a;
  color: #fff;
  border-radius: 10px;
  padding: 10px 12px;
  font: 700 13px/1 Poppins, sans-serif;
  cursor: pointer;
}

.control-buttons button#notes-toggle[aria-pressed="true"] {
  background: #f97316;
  border-color: #f97316;
}

.timer-card {
  margin-top: 16px;
  padding: 12px;
  border-radius: 12px;
  border: 1px solid #e2e8f0;
  background: #f8fafc;
  text-align: center;
}

.timer-label {
  font: 700 11px/1 Poppins, sans-serif;
  text-transform: uppercase;
  letter-spacing: 0.6px;
  color: #64748b;
}

.timer-display {
  font: 700 24px/1.2 Poppins, sans-serif;
  color: #0f172a;
  margin: 6px 0 10px;
}

#timer-toggle {
  border: 1px solid #cbd5e1;
  background: #fff;
  border-radius: 10px;
  padding: 8px 12px;
  font: 700 12px/1 Poppins, sans-serif;
  color: #0f172a;
  cursor: pointer;
}

.how-to-play {
  margin-top: 18px;
}

.how-to-play h2 {
  font: 700 16px/1.3 Poppins, sans-serif;
  margin: 0 0 8px;
  color: #0f172a;
}

.how-to-play ul {
  margin: 0;
  padding-left: 18px;
  font: 400 14px/1.6 Nunito, system-ui, sans-serif;
  color: #475569;
}

.more-from {
  margin: 28px 0 10px;
  padding: 16px;
  border-radius: 14px;
  border: 1px solid #e2e8f0;
  background: #ffffff;
}

.more-from h2 {
  font: 700 18px/1.3 Poppins, sans-serif;
  margin: 0 0 10px;
  color: #0f172a;
}

.more-from ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
  font: 600 14px/1.5 Nunito, system-ui, sans-serif;
}

.more-from a {
  color: #2563eb;
  text-decoration: none;
}

@media (min-width: 900px) {
  .sudoku-layout {
    grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr);
  }

  .sudoku-keypad {
    grid-template-columns: repeat(9, 1fr);
  }

  .sudoku-keypad .key.erase {
    grid-column: span 3;
  }
}