:root {
  color-scheme: light;
  --ink: #17211b;
  --muted: #5f6d65;
  --surface: #f7f4ec;
  --panel: #ffffff;
  --line: #d8d2c4;
  --accent: #256f60;
  --accent-strong: #154d43;
  --mark-o: #1f7a67;
  --mark-x: #9b4d2f;
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  color: var(--ink);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background:
    linear-gradient(135deg, rgba(37, 111, 96, 0.12), transparent 38%),
    linear-gradient(315deg, rgba(155, 77, 47, 0.12), transparent 36%),
    var(--surface);
}

button {
  font: inherit;
}

.page-shell {
  width: min(1040px, calc(100% - 32px));
  min-height: 100vh;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 0.9fr) minmax(320px, 1.1fr);
  align-items: center;
  gap: 56px;
  padding: 48px 0;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(3rem, 6rem, 6.5rem);
  line-height: 0.94;
  letter-spacing: 0;
}

.intro-copy {
  max-width: 460px;
  margin: 24px 0 0;
  color: var(--muted);
  font-size: 1.08rem;
  line-height: 1.7;
}

.game-panel {
  display: grid;
  gap: 20px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: rgba(255, 255, 255, 0.76);
  box-shadow: 0 24px 70px rgba(23, 33, 27, 0.12);
}

.status-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.status {
  margin: 0;
  color: var(--ink);
  font-size: 1rem;
  font-weight: 800;
}

.scoreboard {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  border: 1px solid var(--line);
  border-radius: 8px;
  overflow: hidden;
  background: var(--panel);
}

.scoreboard div {
  min-width: 0;
  padding: 14px;
  text-align: center;
  border-right: 1px solid var(--line);
}

.scoreboard div:last-child {
  border-right: 0;
}

.scoreboard span {
  display: block;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 700;
}

.scoreboard strong {
  display: block;
  margin-top: 4px;
  font-size: 1.35rem;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  aspect-ratio: 1;
}

.cell {
  display: grid;
  place-items: center;
  min-width: 0;
  border: 1px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
  background: var(--panel);
  box-shadow: inset 0 -8px 16px rgba(23, 33, 27, 0.04);
  cursor: pointer;
  font-size: clamp(2.6rem, 5.75rem, 5.75rem);
  font-weight: 900;
  line-height: 1;
  transition: border-color 160ms ease, box-shadow 160ms ease, transform 160ms ease;
}

.cell:hover:not(:disabled),
.cell:focus-visible {
  border-color: var(--accent);
  box-shadow: inset 0 -8px 16px rgba(23, 33, 27, 0.04), 0 0 0 3px rgba(37, 111, 96, 0.16);
  outline: none;
  transform: translateY(-1px);
}

.cell:disabled {
  cursor: default;
}

.cell.mark-o {
  color: var(--mark-o);
}

.cell.mark-x {
  color: var(--mark-x);
}

.cell.winning-cell {
  border-color: var(--accent);
  background: #e8f1ed;
}

.primary-button,
.secondary-button {
  min-height: 44px;
  border: 0;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 800;
}

.primary-button {
  width: 100%;
  color: #ffffff;
  background: var(--accent);
}

.primary-button:hover,
.primary-button:focus-visible {
  background: var(--accent-strong);
  outline: none;
}

.secondary-button {
  flex: 0 0 auto;
  padding: 0 16px;
  color: var(--accent-strong);
  background: #e8f1ed;
}

.secondary-button:hover,
.secondary-button:focus-visible {
  background: #d9e8e2;
  outline: none;
}

@media (max-width: 760px) {
  .page-shell {
    grid-template-columns: 1fr;
    gap: 28px;
    padding: 32px 0;
  }

  h1 {
    font-size: 3.4rem;
  }

  .game-panel {
    padding: 18px;
  }

  .status-row {
    align-items: stretch;
    flex-direction: column;
  }

  .secondary-button {
    width: 100%;
  }
}