:root {
  /* Neobrutalism tokens — matches vikeoo.com */
  --bg: #fafaf9;
  --surface: #ffffff;
  --text: #0a0a0a;
  --text-secondary: #525252;
  --primary: #7c3aed;
  --primary-hover: #6d28d9;
  --accent: #059669;
  --accent-hover: #047857;
  --border: #0a0a0a;
  --border-width: 3px;
  --shadow: 6px 6px 0 0 var(--border);
  --shadow-hover: 10px 10px 0 0 var(--border);
  --radius: 14px;
  --font-sans: "Space Grotesk", "Noto Sans SC", system-ui, sans-serif;
  --font-body: "Noto Sans SC", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
  --font-mono: "Space Mono", "JetBrains Mono", monospace;
  --card-4: #67e8f9;  /* cyan */
  --card-6: #c4b5fd;  /* lavender */
  --card-8: #86efac;  /* light green */
}

* {
  box-sizing: border-box;
}

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

body {
  color: var(--text);
  font-family: var(--font-body);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
}

button {
  font: inherit;
  cursor: pointer;
}

/* Layout */
.app-shell {
  width: min(1100px, calc(100vw - 48px));
  min-height: 100vh;
  margin: 0 auto;
  padding: 48px 0;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 340px;
  gap: 28px;
  align-items: start;
}

.play-area {
  min-width: 0;
}

/* Board */
.board-frame {
  width: min(100%, calc(100vh - 96px));
  aspect-ratio: 1;
  margin: 0 auto;
  padding: clamp(12px, 2vw, 20px);
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  background: var(--card-6);
  box-shadow: var(--shadow);
  transition: transform .12s ease, box-shadow .12s ease;
}

.board-frame:hover {
  transform: translate(-3px, -3px);
  box-shadow: var(--shadow-hover);
}

canvas {
  display: block;
  width: 100%;
  height: 100%;
  border-radius: 8px;
  cursor: pointer;
  touch-action: manipulation;
}

/* Panel */
.panel {
  min-width: 0;
  padding: 24px;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
  transition: transform .12s ease, box-shadow .12s ease;
}

.panel:hover {
  transform: translate(-3px, -3px);
  box-shadow: var(--shadow-hover);
}

.panel-header {
  padding-bottom: 20px;
  border-bottom: var(--border-width) solid var(--border);
}

.eyebrow {
  display: inline-block;
  margin: 0 0 8px;
  padding: 4px 12px;
  color: #fff;
  background: var(--primary);
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  letter-spacing: .08em;
  text-transform: uppercase;
  border: var(--border-width) solid var(--border);
  border-radius: 999px;
  box-shadow: 4px 4px 0 0 var(--border);
}

h1 {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 3.75rem;
  font-weight: 700;
  line-height: 0.92;
  letter-spacing: -.06em;
}

/* Status */
.status-block {
  min-height: 82px;
  margin-top: 20px;
  padding: 16px;
  display: flex;
  gap: 14px;
  align-items: center;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 4px 4px 0 0 var(--border);
}

.turn-stone {
  flex: 0 0 38px;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: var(--border-width) solid var(--border);
}

.turn-stone.black {
  background: var(--text);
}

.turn-stone.white {
  background: var(--surface);
}

.status {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 1.08rem;
  font-weight: 700;
}

.sub-status {
  margin: 5px 0 0;
  color: var(--text-secondary);
  font-size: 0.92rem;
}

/* Mode tabs */
.mode-tabs {
  margin-top: 20px;
  padding: 4px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 4px;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 3px 3px 0 0 var(--border);
}

.tab {
  min-height: 42px;
  border: var(--border-width) solid var(--border);
  border-radius: 10px;
  color: var(--text);
  background: var(--surface);
  font-family: var(--font-sans);
  font-weight: 600;
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease;
}

.tab:hover {
  transform: translate(-2px, -2px);
  box-shadow: 4px 4px 0 0 var(--border);
}

.tab:active {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 0 var(--border);
}

.tab.active {
  color: #fff;
  background: var(--accent);
  box-shadow: 4px 4px 0 0 var(--border);
}

/* Difficulty tabs */
.difficulty-tabs {
  margin-top: 12px;
  padding: 4px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 4px;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 3px 3px 0 0 var(--border);
}

.difficulty-tabs.hidden {
  display: none;
}

.level {
  min-height: 38px;
  border: var(--border-width) solid var(--border);
  border-radius: 10px;
  color: var(--text);
  background: var(--surface);
  font-family: var(--font-sans);
  font-size: 0.92rem;
  font-weight: 600;
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease;
}

.level:hover {
  transform: translate(-2px, -2px);
  box-shadow: 4px 4px 0 0 var(--border);
}

.level:active {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 0 var(--border);
}

.level.active {
  color: #fff;
  background: var(--accent);
  box-shadow: 4px 4px 0 0 var(--border);
}

.level[data-level="hell"].active {
  background: #ef4444;
  box-shadow: 4px 4px 0 0 var(--border);
}

/* Audio toggles */
.audio-toggles {
  margin-top: 12px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.toggle-button {
  min-height: 42px;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  color: var(--text-secondary);
  background: var(--surface);
  font-family: var(--font-sans);
  font-weight: 600;
  box-shadow: 3px 3px 0 0 var(--border);
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease, color .12s ease;
}

.toggle-button:hover {
  transform: translate(-2px, -2px);
  box-shadow: 5px 5px 0 0 var(--border);
}

.toggle-button:active {
  transform: translate(2px, 2px);
  box-shadow: 1px 1px 0 0 var(--border);
}

.toggle-button.active {
  color: #fff;
  background: var(--accent);
  box-shadow: 4px 4px 0 0 var(--border);
}

.toggle-button:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 3px;
}

/* Stats grid */
.stats-grid {
  margin-top: 20px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.stats-grid div {
  min-width: 0;
  min-height: 72px;
  padding: 12px 10px;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 3px 3px 0 0 var(--border);
}

.stats-grid span {
  display: block;
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-family: var(--font-mono);
  text-transform: uppercase;
  letter-spacing: .04em;
}

.stats-grid strong {
  display: block;
  margin-top: 7px;
  font-family: var(--font-sans);
  font-size: 1.45rem;
  font-weight: 700;
}

/* Controls */
.controls {
  margin-top: 20px;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.primary-button,
.ghost-button {
  min-height: 46px;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-weight: 700;
  box-shadow: var(--shadow);
  transition: transform .12s ease, box-shadow .12s ease, background .12s ease;
}

.primary-button:hover,
.ghost-button:hover {
  transform: translate(-3px, -3px);
  box-shadow: var(--shadow-hover);
}

.primary-button:active,
.ghost-button:active {
  transform: translate(3px, 3px);
  box-shadow: 2px 2px 0 0 var(--border);
}

.primary-button {
  color: #fff;
  background: var(--accent);
}

.primary-button:hover {
  background: var(--accent-hover);
}

.ghost-button {
  color: var(--text);
  background: var(--surface);
}

.primary-button:focus-visible,
.ghost-button:focus-visible,
.tab:focus-visible,
canvas:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 3px;
}

/* Move list */
.move-list {
  height: 164px;
  margin: 20px 0 0;
  padding: 12px 12px 12px 32px;
  overflow: auto;
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: 3px 3px 0 0 var(--border);
  color: var(--text);
  font-family: var(--font-mono);
  font-size: 0.9rem;
}

.move-list:empty::before {
  content: "等待落子";
  display: block;
  margin-left: -18px;
  color: var(--text-secondary);
}

.move-list li {
  padding: 5px 0;
}

/* Responsive */
@media (max-width: 900px) {
  .app-shell {
    min-height: auto;
    grid-template-columns: 1fr;
    align-items: start;
    padding: 24px 0;
  }

  .board-frame {
    width: min(100%, 720px);
  }

  .panel {
    width: min(100%, 720px);
    margin: 0 auto;
  }
}

@media (max-width: 560px) {
  .app-shell {
    width: min(100vw - 20px, 720px);
    padding: 10px 0 18px;
    gap: 12px;
  }

  .board-frame {
    padding: 8px;
  }

  .panel {
    padding: 14px;
  }

  h1 {
    font-size: 2.6rem;
  }

  .status-block,
  .stats-grid,
  .controls,
  .mode-tabs,
  .move-list {
    margin-top: 12px;
  }

  .move-list {
    height: 112px;
  }
}

@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: .01ms !important;
    transition-duration: .01ms !important;
  }
}

/* ---- Game Over Overlay ---- */
.overlay-backdrop {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(10, 10, 10, 0.55);
  backdrop-filter: blur(4px);
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
}

.overlay-backdrop.visible {
  opacity: 1;
  pointer-events: auto;
}

.overlay-card {
  width: min(420px, calc(100vw - 40px));
  padding: 40px 32px 32px;
  text-align: center;
  background: var(--surface);
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  box-shadow: 8px 8px 0 0 var(--border);
  transform: translateY(32px) scale(0.92);
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.overlay-backdrop.visible .overlay-card {
  transform: translateY(0) scale(1);
}

.overlay-emoji {
  font-size: 3.2rem;
  line-height: 1;
  margin-bottom: 12px;
  animation: overlay-bounce 0.5s ease 0.2s both;
}

@keyframes overlay-bounce {
  0%   { transform: scale(0.4) rotate(-12deg); opacity: 0; }
  60%  { transform: scale(1.15) rotate(4deg); }
  100% { transform: scale(1) rotate(0); opacity: 1; }
}

.overlay-title {
  margin: 0 0 8px;
  font-family: var(--font-sans);
  font-size: 2rem;
  font-weight: 700;
  line-height: 1.1;
  letter-spacing: -0.03em;
}

.overlay-sub {
  margin: 0 0 28px;
  color: var(--text-secondary);
  font-size: 1rem;
  font-family: var(--font-mono);
}

.overlay-btn {
  display: inline-block;
  min-width: 180px;
  min-height: 50px;
  padding: 0 28px;
  color: #fff;
  background: var(--primary);
  border: var(--border-width) solid var(--border);
  border-radius: var(--radius);
  font-family: var(--font-sans);
  font-size: 1.1rem;
  font-weight: 700;
  box-shadow: var(--shadow);
  transition: transform 0.12s ease, box-shadow 0.12s ease, background 0.12s ease;
}

.overlay-btn:hover {
  background: var(--primary-hover);
  transform: translate(-3px, -3px);
  box-shadow: var(--shadow-hover);
}

.overlay-btn:active {
  transform: translate(3px, 3px);
  box-shadow: 2px 2px 0 0 var(--border);
}

.overlay-btn:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 3px;
}

.overlay-hint {
  margin: 16px 0 0;
  color: var(--text-secondary);
  font-size: 0.78rem;
  font-family: var(--font-mono);
  opacity: 0.7;
}

.overlay-win .overlay-card    { border-color: var(--accent); box-shadow: 8px 8px 0 0 var(--accent); }
.overlay-win .overlay-btn     { background: var(--accent); }
.overlay-win .overlay-btn:hover { background: var(--accent-hover); }

.overlay-lose .overlay-card   { border-color: #ef4444; box-shadow: 8px 8px 0 0 #ef4444; }
.overlay-lose .overlay-btn    { background: #ef4444; }
.overlay-lose .overlay-btn:hover { background: #dc2626; }

.overlay-draw .overlay-card   { border-color: var(--primary); box-shadow: 8px 8px 0 0 var(--primary); }