:root {
  /* Design tokens (dark is the default theme) */
  --bg: #060a14;
  --text: #e9edf9;
  --muted: #8d96b3;
  --line: rgba(150, 166, 220, 0.16);
  --glass-bg: rgba(13, 19, 38, 0.55);
  --glass-hi: rgba(255, 255, 255, 0.07);
  --blur: 18px;
  --accent: #67e8f9;
  --neon-a: #22d3ee;
  --neon-b: #8b5cf6;
  --neon-c: #f472b6;
  --grad-neon: linear-gradient(135deg, var(--neon-a), var(--neon-b) 52%, var(--neon-c));
  --glow-accent: 0 0 22px rgba(34, 211, 238, 0.35);
  --shadow-card: 0 18px 48px rgba(1, 4, 16, 0.55);
  --shadow-card-hover: 0 26px 64px rgba(1, 4, 16, 0.68);
  --r-md: 12px;
  --r-lg: 18px;
  --font-sans: "Space Grotesk", "Noto Sans SC", "PingFang SC", "Microsoft YaHei", Arial, sans-serif;
  --ease-spring: cubic-bezier(0.2, 0.9, 0.26, 1.12);
  --ease-out: cubic-bezier(0.22, 0.74, 0.25, 1);
  /* Semantic state colors */
  --state-select: #ff9b3d;
  --state-select-deep: #ef761d;
  --state-select-text: #ffb066;
  --state-lock-a: #5eeab0;
  --state-lock-b: #0da678;
  /* Card face gradient stops */
  --card-face-a: #111a36;
  --card-face-b: #0a1126;
  /* Functional timing: matched to JS setTimeout/sleep values, do not retune */
  --fast: 220ms;
  --medium: 460ms;
  --slow: 680ms;
}

[data-theme="light"] {
  --bg: #edf1fb;
  --text: #18213c;
  --muted: #5a6580;
  --line: rgba(28, 44, 92, 0.16);
  --glass-bg: rgba(255, 255, 255, 0.6);
  --glass-hi: rgba(255, 255, 255, 0.9);
  --accent: #1557e6;
  --neon-a: #0284c7;
  --neon-b: #7c3aed;
  --neon-c: #db2777;
  --glow-accent: 0 0 22px rgba(2, 132, 199, 0.28);
  --shadow-card: 0 18px 44px rgba(28, 44, 92, 0.14);
  --shadow-card-hover: 0 26px 58px rgba(28, 44, 92, 0.2);
  --state-select-text: #d9630f;
  --card-face-a: #ffffff;
  --card-face-b: #e9efff;
}

* {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  color: var(--text);
  font-family: var(--font-sans);
  background:
    radial-gradient(1100px 720px at 10% -12%, rgba(34, 211, 238, 0.14), transparent 62%),
    radial-gradient(940px 640px at 92% 112%, rgba(139, 92, 246, 0.16), transparent 62%),
    var(--bg);
  letter-spacing: 0;
  overflow-x: hidden;
}

[data-theme="light"] body {
  background:
    radial-gradient(1100px 720px at 10% -12%, rgba(2, 132, 199, 0.12), transparent 62%),
    radial-gradient(940px 640px at 92% 112%, rgba(124, 58, 237, 0.1), transparent 62%),
    var(--bg);
}

/* Slow drifting neon orbs behind the glass panels (decorative, transform only) */
body::before,
body::after {
  content: "";
  position: fixed;
  z-index: 0;
  width: 48vmax;
  height: 48vmax;
  border-radius: 50%;
  pointer-events: none;
  will-change: transform;
}

body::before {
  top: -14vmax;
  left: -12vmax;
  background: radial-gradient(closest-side, rgba(34, 211, 238, 0.2), transparent 72%);
  animation: orb-drift-a 36s ease-in-out infinite alternate;
}

body::after {
  right: -14vmax;
  bottom: -16vmax;
  background: radial-gradient(closest-side, rgba(244, 114, 182, 0.16), transparent 72%);
  animation: orb-drift-b 44s ease-in-out infinite alternate;
}

[data-theme="light"] body::before {
  background: radial-gradient(closest-side, rgba(2, 132, 199, 0.14), transparent 72%);
}

[data-theme="light"] body::after {
  background: radial-gradient(closest-side, rgba(219, 39, 119, 0.1), transparent 72%);
}

@keyframes orb-drift-a {
  from {
    transform: translate3d(0, 0, 0) scale(1);
  }
  to {
    transform: translate3d(9vw, 8vh, 0) scale(1.14);
  }
}

@keyframes orb-drift-b {
  from {
    transform: translate3d(0, 0, 0) scale(1.08);
  }
  to {
    transform: translate3d(-8vw, -7vh, 0) scale(1);
  }
}

/* Entrance animations (decorative) */
@keyframes rise-in {
  from {
    opacity: 0;
    transform: translateY(18px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes author-in {
  from {
    opacity: 0;
    transform: translateX(-50%) translateY(14px);
  }
  to {
    opacity: 1;
    transform: translateX(-50%) translateY(0);
  }
}

@keyframes card-fade {
  from {
    opacity: 0;
  }
}

button {
  font: inherit;
}

.app {
  position: relative;
  z-index: 1;
  width: min(1180px, calc(100vw - 36px));
  min-height: 100vh;
  margin: 0 auto;
  padding: 28px 0 78px;
}

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  margin-bottom: 20px;
  padding-right: 58px;
  animation: rise-in 560ms var(--ease-out) both;
}

.title-group h1 {
  margin: 0;
  font-size: clamp(30px, 4vw, 48px);
  line-height: 1.05;
  font-weight: 800;
  background: var(--grad-neon);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  filter: drop-shadow(0 0 20px rgba(34, 211, 238, 0.22));
}

.title-group p {
  margin: 8px 0 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.6;
}

.status-pill {
  min-width: 170px;
  padding: 12px 16px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--glass-bg);
  box-shadow: var(--shadow-card), inset 0 1px 0 var(--glass-hi);
  text-align: center;
  -webkit-backdrop-filter: blur(var(--blur));
  backdrop-filter: blur(var(--blur));
}

.status-label {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
}

.status-value {
  display: block;
  margin-top: 2px;
  color: var(--accent);
  font-size: 20px;
  font-weight: 800;
}

.layout {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 320px;
  gap: 18px;
  align-items: start;
}

.stage,
.side-panel {
  border: 1px solid var(--line);
  border-radius: var(--r-lg);
  background: var(--glass-bg);
  box-shadow: var(--shadow-card), inset 0 1px 0 var(--glass-hi);
  -webkit-backdrop-filter: blur(var(--blur));
  backdrop-filter: blur(var(--blur));
}

.stage {
  padding: clamp(16px, 2vw, 24px);
  animation: rise-in 560ms var(--ease-out) 90ms both;
}

.stats {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 18px;
}

.stat {
  min-height: 76px;
  padding: 13px 14px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--glass-bg);
  transition:
    transform var(--fast) var(--ease-out),
    box-shadow var(--fast) ease,
    border-color var(--fast) ease;
}

.stat:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-card-hover), var(--glow-accent);
}

.stat span {
  display: block;
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  white-space: nowrap;
}

.stat strong {
  display: block;
  margin-top: 7px;
  color: var(--text);
  font-size: 25px;
  line-height: 1.05;
  font-weight: 850;
}

.stat .small-value {
  font-size: 18px;
  line-height: 1.22;
  word-break: break-word;
}

.board-wrap {
  position: relative;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background:
    linear-gradient(135deg, var(--glass-hi), transparent 60%),
    linear-gradient(135deg, rgba(34, 211, 238, 0.07), rgba(139, 92, 246, 0.08));
  overflow: hidden;
}

.board {
  position: relative;
  display: grid;
  grid-template-columns: repeat(5, minmax(86px, 1fr));
  gap: clamp(11px, 1.45vw, 16px);
  transform-style: preserve-3d;
}

.card {
  position: relative;
  display: block;
  width: 100%;
  aspect-ratio: 0.72;
  padding: 0;
  border: 0;
  border-radius: var(--r-md);
  background: transparent;
  cursor: pointer;
  perspective: 1100px;
  transform: translate(0, 0) rotate(0deg) scale(1);
  transition:
    transform var(--slow) cubic-bezier(0.2, 0.85, 0.23, 1),
    filter var(--medium) ease,
    opacity var(--medium) ease;
  will-change: transform;
  animation: card-fade 480ms var(--ease-out) both;
}

.card:nth-child(2) {
  animation-delay: 36ms;
}

.card:nth-child(3) {
  animation-delay: 72ms;
}

.card:nth-child(4) {
  animation-delay: 108ms;
}

.card:nth-child(5) {
  animation-delay: 144ms;
}

.card:nth-child(6) {
  animation-delay: 180ms;
}

.card:nth-child(7) {
  animation-delay: 216ms;
}

.card:nth-child(8) {
  animation-delay: 252ms;
}

.card:nth-child(9) {
  animation-delay: 288ms;
}

.card:nth-child(10) {
  animation-delay: 324ms;
}

.card:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 4px;
}

.card[disabled] {
  cursor: not-allowed;
  opacity: 1;
}

.card.is-stacked {
  transform:
    translate(var(--stack-x, 0px), var(--stack-y, 0px))
    rotate(var(--stack-rot, 0deg))
    scale(0.88);
  z-index: 20;
}

.card.is-dealing {
  z-index: 25;
}

.card.is-stacked .card-inner {
  animation: shuffle-breathe 520ms ease-in-out infinite alternate;
}

.card.is-dealing .card-inner {
  animation: deal-pop 560ms cubic-bezier(0.18, 0.9, 0.22, 1) both;
}

.card-inner {
  position: absolute;
  inset: 0;
  border-radius: inherit;
  transform-style: preserve-3d;
  transition:
    transform var(--medium) cubic-bezier(0.22, 0.74, 0.25, 1),
    box-shadow var(--fast) ease;
  box-shadow: var(--shadow-card);
}

.card:not([disabled]):hover .card-inner {
  box-shadow: var(--shadow-card-hover), var(--glow-accent);
}

@keyframes shuffle-breathe {
  from {
    transform: translateY(0) rotateZ(-1.2deg) scale(0.98);
  }
  to {
    transform: translateY(-7px) rotateZ(1.2deg) scale(1.03);
  }
}

@keyframes deal-pop {
  0% {
    transform: translateY(-10px) rotateZ(var(--deal-rot, 0deg)) scale(0.92);
  }
  58% {
    transform: translateY(5px) rotateZ(calc(var(--deal-rot, 0deg) * -0.35)) scale(1.055);
  }
  100% {
    transform: translateY(0) rotateZ(0deg) scale(1);
  }
}

.card.is-revealed .card-inner,
.card.is-preview .card-inner,
.card.is-locked .card-inner {
  transform: rotateY(180deg);
}

.card-face {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  border-radius: inherit;
  backface-visibility: hidden;
  overflow: hidden;
}

.card-front {
  border: 1px solid var(--line);
  background:
    linear-gradient(150deg, var(--glass-hi), transparent 55%),
    radial-gradient(120% 120% at 20% 0%, rgba(34, 211, 238, 0.16), transparent 55%),
    linear-gradient(145deg, var(--card-face-a), var(--card-face-b));
  color: var(--accent);
}

.card-front::before {
  content: "";
  position: absolute;
  inset: 9px;
  border: 1px solid var(--line);
  border-radius: calc(var(--r-md) - 1px);
}

.card-front::after {
  content: "";
  position: absolute;
  width: 80%;
  height: 80%;
  border-radius: 50%;
  background: radial-gradient(circle, rgba(34, 211, 238, 0.14), transparent 68%);
}

.question {
  position: relative;
  z-index: 1;
  font-size: clamp(36px, 5vw, 58px);
  line-height: 1;
  font-weight: 900;
  background: var(--grad-neon);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  filter: drop-shadow(0 6px 16px rgba(34, 211, 238, 0.3));
}

.card-back {
  transform: rotateY(180deg);
  border: 1px solid var(--line);
  background:
    linear-gradient(150deg, var(--glass-hi), transparent 50%),
    radial-gradient(120% 120% at 80% 0%, rgba(139, 92, 246, 0.18), transparent 55%),
    linear-gradient(145deg, var(--card-face-a), var(--card-face-b));
  color: var(--text);
}

.card.is-selected .card-back {
  border-color: rgba(255, 155, 61, 0.75);
  background:
    linear-gradient(150deg, rgba(255, 255, 255, 0.1), transparent 50%),
    radial-gradient(120% 120% at 80% 0%, rgba(255, 155, 61, 0.28), transparent 58%),
    linear-gradient(145deg, var(--card-face-a), var(--card-face-b));
  color: var(--state-select-text);
}

.card.is-selected {
  transform: scale(1.035);
  filter: drop-shadow(0 22px 30px rgba(239, 118, 29, 0.28));
  z-index: 30;
}

.card.is-locked .card-back {
  border-color: rgba(94, 234, 176, 0.85);
  background: linear-gradient(145deg, var(--state-lock-a), var(--state-lock-b));
  color: #ffffff;
  box-shadow: 0 0 26px rgba(52, 211, 153, 0.35);
}

.card-number {
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
  padding: 10px;
  font-size: clamp(34px, 4.8vw, 60px);
  line-height: 1;
  font-weight: 900;
  text-align: center;
  background: var(--grad-neon);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.card.is-locked .card-number {
  background: none;
  color: #ffffff;
  text-shadow: 0 8px 18px rgba(0, 104, 76, 0.3);
}

.card.is-selected .card-number {
  background: none;
  color: var(--state-select-text);
  font-size: clamp(22px, 2.2vw, 31px);
  letter-spacing: 0;
}

.card-lock {
  position: absolute;
  top: 9px;
  right: 9px;
  display: none;
  padding: 4px 7px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.85);
  color: #0a6b54;
  font-size: 11px;
  font-weight: 800;
}

.card.is-locked .card-lock {
  display: block;
}

.controls {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-top: 18px;
}

.control-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 10px;
}

.message {
  min-height: 24px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.45;
}

.reset-btn {
  min-width: 118px;
  padding: 12px 18px;
  border: 0;
  border-radius: var(--r-md);
  background: var(--grad-neon);
  color: #ffffff;
  box-shadow: 0 16px 30px rgba(34, 211, 238, 0.25);
  font-size: 16px;
  font-weight: 800;
  cursor: pointer;
  transition:
    transform var(--fast) var(--ease-spring),
    box-shadow var(--fast) ease,
    opacity var(--fast) ease,
    filter var(--fast) ease;
}

.reset-btn:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 18px 36px rgba(34, 211, 238, 0.35), var(--glow-accent);
  filter: brightness(1.06);
}

.reset-btn:active:not(:disabled) {
  transform: scale(0.94);
}

.reset-btn:disabled {
  opacity: 0.48;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.reset-btn.restart-btn {
  border: 1px solid var(--line);
  background: transparent;
  color: var(--text);
  box-shadow: none;
}

.reset-btn.restart-btn:hover:not(:disabled) {
  border-color: var(--accent);
  box-shadow: var(--glow-accent);
}

.side-panel {
  padding: 18px;
  position: sticky;
  top: 18px;
  animation: rise-in 560ms var(--ease-out) 180ms both;
}

.side-panel h2 {
  margin: 0 0 12px;
  color: var(--text);
  font-size: 22px;
  line-height: 1.15;
}

.history-list {
  display: grid;
  gap: 10px;
  max-height: 572px;
  overflow: auto;
  padding-right: 4px;
}

.history-empty,
.history-item {
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--glass-bg);
}

.history-empty {
  padding: 18px;
  color: var(--muted);
  font-size: 14px;
  line-height: 1.65;
}

.history-item {
  padding: 13px;
  transition:
    transform var(--fast) var(--ease-out),
    box-shadow var(--fast) ease,
    border-color var(--fast) ease;
}

.history-item:hover {
  transform: translateY(-3px);
  border-color: var(--accent);
  box-shadow: var(--shadow-card-hover);
}

.history-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  margin-bottom: 8px;
}

.history-round {
  color: var(--accent);
  font-weight: 850;
}

.history-selected {
  display: inline-grid;
  place-items: center;
  min-width: 34px;
  height: 30px;
  border-radius: 999px;
  background: linear-gradient(135deg, var(--state-select), var(--state-select-deep));
  color: #ffffff;
  font-weight: 900;
  box-shadow: 0 6px 16px rgba(239, 118, 29, 0.35);
}

.history-meta {
  display: grid;
  gap: 4px;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.45;
}

.author-button {
  position: fixed;
  left: 50%;
  bottom: 16px;
  z-index: 100;
  display: inline-flex;
  align-items: center;
  gap: 10px;
  transform: translateX(-50%);
  padding: 8px 14px 8px 9px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--glass-bg);
  color: var(--text);
  box-shadow:
    var(--shadow-card),
    inset 0 1px 0 var(--glass-hi);
  font-size: 12px;
  line-height: 1;
  cursor: pointer;
  -webkit-backdrop-filter: blur(var(--blur));
  backdrop-filter: blur(var(--blur));
  transition:
    opacity var(--fast) ease,
    color var(--fast) ease,
    border-color var(--fast) ease,
    box-shadow var(--fast) ease,
    transform var(--fast) ease;
  animation: author-in 560ms var(--ease-out) 260ms both;
}

.author-button:hover:not(:disabled) {
  border-color: var(--accent);
  box-shadow: var(--shadow-card-hover), var(--glow-accent);
}

.author-mark {
  display: grid;
  place-items: center;
  width: 31px;
  height: 31px;
  flex: 0 0 31px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 30% 24%, rgba(255, 255, 255, 0.16), transparent 34%),
    linear-gradient(135deg, #111827, #020617);
  color: #ffffff;
  box-shadow: 0 10px 20px rgba(2, 6, 23, 0.22);
}

.author-mark svg {
  width: 20px;
  height: 20px;
  display: block;
}

.author-copy {
  display: grid;
  gap: 2px;
  text-align: left;
  white-space: nowrap;
}

.author-kicker {
  color: var(--muted);
  font-size: 9px;
  font-weight: 850;
  letter-spacing: 1.2px;
  text-transform: uppercase;
}

.author-name {
  color: var(--text);
  font-size: 12px;
  font-weight: 850;
  letter-spacing: 0;
}

.author-button:disabled {
  cursor: default;
  opacity: 1;
}

.author-button:disabled:hover {
  transform: translateX(-50%);
}

.theme-toggle {
  position: fixed;
  top: 16px;
  right: 16px;
  z-index: 200;
  display: grid;
  place-items: center;
  width: 44px;
  height: 44px;
  padding: 0;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--glass-bg);
  color: var(--text);
  box-shadow: var(--shadow-card), inset 0 1px 0 var(--glass-hi);
  cursor: pointer;
  -webkit-backdrop-filter: blur(var(--blur));
  backdrop-filter: blur(var(--blur));
  transition:
    transform var(--fast) var(--ease-spring),
    box-shadow var(--fast) ease,
    border-color var(--fast) ease;
}

.theme-toggle::before {
  content: "☀";
  font-size: 19px;
  line-height: 1;
}

[data-theme="light"] .theme-toggle::before {
  content: "☾";
}

.theme-toggle:hover {
  border-color: var(--accent);
  box-shadow: var(--shadow-card-hover), var(--glow-accent);
}

.theme-toggle:active {
  transform: scale(0.92);
}

@media (max-width: 960px) {
  .layout {
    grid-template-columns: 1fr;
  }

  .side-panel {
    position: static;
  }

  .history-list {
    max-height: 360px;
  }
}

@media (max-width: 720px) {
  .app {
    width: min(100vw - 22px, 620px);
    padding-top: 18px;
  }

  .topbar {
    align-items: stretch;
    flex-direction: column;
    padding-right: 0;
    padding-top: 44px;
  }

  .status-pill {
    min-width: 0;
  }

  .stats {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .board-wrap {
    padding: 12px;
  }

  .board {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .card {
    aspect-ratio: 1.08;
  }

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

  .reset-btn {
    width: 100%;
  }

  .control-actions {
    width: 100%;
  }

  .control-actions .reset-btn {
    flex: 1 1 150px;
    width: auto;
  }
}

/* Decorative animations only; functional flip/shuffle motion stays intact */
@media (prefers-reduced-motion: reduce) {
  body::before,
  body::after,
  .topbar,
  .stage,
  .side-panel,
  .author-button,
  .card {
    animation: none;
  }
}