:root {
  color-scheme: light;
  --sudoku-bg: #f6f6f4;
  --sudoku-card: #ffffff;
  --sudoku-ink: #161616;
  --sudoku-muted: #6f6f73;
  --sudoku-line: rgba(17, 17, 17, 0.12);
  --sudoku-strong: #1d1d1f;
  --sudoku-soft: #f0f0ef;
  --sudoku-selected: #cfd1d4;
  --sudoku-error: #d93b3b;
  --sudoku-radius: 8px;
}

* {
  box-sizing: border-box;
}

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

body {
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  color: var(--sudoku-ink);
  background: var(--sudoku-bg);
}

button {
  font: inherit;
  cursor: pointer;
}

.sudoku-page {
  width: min(1180px, 100%);
  margin: 0 auto;
  padding: 24px 20px 64px;
}

.sudoku-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 28px;
}

.sudoku-nav-back,
.sudoku-nav-status {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 10px 14px;
  border: 1px solid var(--sudoku-line);
  border-radius: var(--sudoku-radius);
  color: var(--sudoku-ink);
  background: rgba(255, 255, 255, 0.78);
  text-decoration: none;
  box-shadow: 0 12px 28px rgba(17, 17, 17, 0.06);
}

.sudoku-nav-status {
  color: var(--sudoku-muted);
}

.sudoku-layout {
  display: grid;
  grid-template-columns: minmax(320px, 460px) minmax(280px, 1fr);
  gap: 32px;
  align-items: start;
}

.sudoku-game-card {
  position: relative;
  display: grid;
  gap: 16px;
  padding: 18px;
  border: 1px solid var(--sudoku-line);
  border-radius: var(--sudoku-radius);
  background: var(--sudoku-card);
  box-shadow: 0 22px 48px rgba(15, 23, 42, 0.08);
}

.sudoku-board {
  display: grid;
  grid-template-columns: repeat(9, 1fr);
  width: min(100%, 420px);
  aspect-ratio: 1;
  margin: 0 auto;
  border: 2px solid var(--sudoku-strong);
  background: #fff;
}

.sudoku-cell {
  display: grid;
  place-items: center;
  border: 1px solid rgba(17, 17, 17, 0.22);
  background: #fff;
  color: #4c4c50;
  font-size: clamp(18px, 5vw, 30px);
  font-weight: 500;
  line-height: 1;
  user-select: none;
}

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

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

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

.sudoku-cell.is-given {
  color: #111;
  font-weight: 800;
}

.sudoku-cell.is-selected {
  background: var(--sudoku-selected);
  color: #111;
}

.sudoku-cell.is-related {
  background: #f1f1f0;
}

.sudoku-cell.is-error {
  color: var(--sudoku-error);
}

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

.sudoku-keypad button,
.sudoku-action {
  min-height: 38px;
  border: 1px solid var(--sudoku-line);
  border-radius: var(--sudoku-radius);
  background: #fff;
  color: var(--sudoku-ink);
  font-weight: 700;
}

.sudoku-keypad button:hover,
.sudoku-action:hover {
  border-color: rgba(17, 17, 17, 0.26);
  background: #f8f8f7;
}

.sudoku-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 8px;
}

.sudoku-action {
  padding: 0 12px;
}

.sudoku-action--primary {
  border-color: #111;
  background: #111;
  color: #fff;
}

.sudoku-message {
  min-height: 20px;
  margin: 0;
  color: var(--sudoku-muted);
  font-size: 13px;
  font-weight: 650;
}

.sudoku-detail {
  display: grid;
  gap: 18px;
  padding-top: 8px;
}

.sudoku-eyebrow {
  margin: 0;
  color: var(--sudoku-muted);
  font-size: 13px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.sudoku-detail h1 {
  margin: 0;
  max-width: 520px;
  font-size: clamp(38px, 7vw, 72px);
  line-height: 0.96;
  letter-spacing: 0;
}

.sudoku-detail p:not(.sudoku-eyebrow) {
  margin: 0;
  max-width: 560px;
  color: #34343a;
  font-size: 17px;
  line-height: 1.65;
}

.sudoku-detail-list {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.sudoku-detail-list span {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  padding: 8px 12px;
  border: 1px solid var(--sudoku-line);
  border-radius: var(--sudoku-radius);
  background: #fff;
  color: #34343a;
  font-size: 13px;
  font-weight: 650;
}

.sudoku-confetti {
  position: fixed;
  top: 50%;
  left: 50%;
  width: 7px;
  height: 7px;
  border-radius: 50%;
  pointer-events: none;
  animation: sudokuPop 760ms ease-out forwards;
}

@keyframes sudokuPop {
  to {
    transform: translate(var(--x), var(--y)) scale(0.4);
    opacity: 0;
  }
}

@media (max-width: 760px) {
  .sudoku-layout {
    grid-template-columns: 1fr;
  }

  .sudoku-nav {
    align-items: stretch;
    flex-direction: column;
    gap: 10px;
  }
}