:root {
  color-scheme: light;
  --ink: #161616;
  --muted: #62635f;
  --paper: #f9f6ee;
  --panel: #fffdfa;
  --line: #252525;
  --grid: #d9d1bf;
  --x: #cb3d3d;
  --o: #216e8d;
  --x-soft: #ffe1df;
  --o-soft: #d9f1f8;
  --focus: #6750a4;
  --shadow: 0 20px 50px rgba(30, 25, 15, 0.12);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  color: var(--ink);
  background:
    linear-gradient(rgba(22, 22, 22, 0.035) 1px, transparent 1px),
    linear-gradient(90deg, rgba(22, 22, 22, 0.035) 1px, transparent 1px),
    var(--paper);
  background-size: 32px 32px;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button {
  font: inherit;
}

.app {
  width: min(1120px, calc(100vw - 32px));
  min-height: 100vh;
  margin: 0 auto;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 28px;
  align-items: center;
  padding: 32px 0;
}

.play-area,
.side-panel {
  background: rgba(255, 253, 250, 0.86);
  border: 1px solid rgba(37, 37, 37, 0.12);
  box-shadow: var(--shadow);
}

.play-area {
  padding: 24px;
}

.side-panel {
  padding: 18px;
}

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

.eyebrow {
  margin: 0 0 4px;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 800;
  text-transform: uppercase;
}

h1 {
  margin: 0;
  font-size: clamp(2.2rem, 4.8rem, 5rem);
  line-height: 0.92;
}

.icon-button {
  width: 44px;
  height: 44px;
  display: inline-grid;
  place-items: center;
  border: 2px solid var(--line);
  border-radius: 8px;
  color: var(--ink);
  background: var(--panel);
  cursor: pointer;
  transition: transform 150ms ease, background 150ms ease;
}

.icon-button:hover {
  background: #eee6d6;
  transform: translateY(-1px);
}

.icon-button:focus-visible,
.cell:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}

.status-row {
  margin: 24px 0 18px;
}

.turn-badge {
  min-width: 104px;
  padding: 9px 12px;
  border: 2px solid currentColor;
  border-radius: 8px;
  font-weight: 900;
  text-align: center;
}

.player-x {
  color: var(--x);
  background: var(--x-soft);
}

.player-o {
  color: var(--o);
  background: var(--o-soft);
}

.message {
  color: var(--muted);
  font-size: 0.95rem;
  text-align: right;
}

.board {
  aspect-ratio: 1;
  width: min(100%, 620px);
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  grid-template-rows: repeat(5, 1fr);
  border: 3px solid var(--line);
  background: var(--line);
  gap: 3px;
}

.cell {
  min-width: 0;
  border: 0;
  display: grid;
  place-items: center;
  background: var(--panel);
  color: var(--ink);
  cursor: pointer;
  position: relative;
  isolation: isolate;
}

.cell::before {
  content: "";
  position: absolute;
  inset: 13%;
  border: 2px dashed rgba(37, 37, 37, 0.14);
  border-radius: 50%;
  opacity: 0;
  transition: opacity 120ms ease;
}

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

.cell[disabled] {
  cursor: default;
}

.mark {
  display: grid;
  place-items: center;
  width: 72%;
  height: 72%;
  border-radius: 50%;
  font-size: clamp(2rem, 8vw, 4.4rem);
  font-weight: 950;
  line-height: 1;
  transform: scale(0.96);
  animation: pop 180ms ease-out;
}

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

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

.cell.captured {
  animation: capture 360ms ease-out;
}

.cell.winning {
  background: #fff0aa;
}

.score-row {
  margin-bottom: 16px;
}

.score-box {
  flex: 1;
  padding: 14px;
  border: 1px solid rgba(37, 37, 37, 0.14);
  border-radius: 8px;
  background: var(--panel);
}

.score-label {
  display: block;
  color: var(--muted);
  font-size: 0.76rem;
  font-weight: 800;
  text-transform: uppercase;
}

.score-box strong {
  display: block;
  margin-top: 4px;
  font-size: 2rem;
}

.rule-card {
  padding: 14px;
  border: 1px solid rgba(37, 37, 37, 0.14);
  border-radius: 8px;
  background: #f5efe2;
}

.rule-card h2 {
  margin: 0 0 8px;
  font-size: 1rem;
}

.rule-card p {
  margin: 0;
  color: var(--muted);
  line-height: 1.45;
}

.move-list {
  max-height: 320px;
  margin: 16px 0 0;
  padding: 0 0 0 24px;
  overflow: auto;
  color: var(--muted);
}

.move-list li {
  margin-bottom: 8px;
  padding-left: 4px;
}

@keyframes pop {
  from {
    opacity: 0;
    transform: scale(0.66);
  }
}

@keyframes capture {
  35% {
    background: #202020;
  }
}

@media (max-width: 860px) {
  .app {
    min-height: auto;
    grid-template-columns: 1fr;
    align-items: start;
    padding: 18px 0;
  }

  .play-area,
  .side-panel {
    padding: 16px;
  }

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

  .message {
    text-align: left;
  }

  h1 {
    font-size: 3rem;
  }

  .move-list {
    max-height: 180px;
  }
}