*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ===== Classic Theme (default) ===== */

:root,
[data-theme="classic"] {
  --board-bg: #2e8b57;
  --board-border: #1a5c38;
  --cell-border: #246b45;
  --bg: #1a1a2e;
  --surface: #16213e;
  --text: #e0e0e0;
  --accent: #4fc3f7;
  --black-disc: #1a1a1a;
  --white-disc: #f0f0f0;
  --valid-hint: rgba(255, 255, 255, 0.25);
  --font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  --disc-radius: 50%;
  --cell-radius: 0px;
  --board-radius: 10px;
  --board-wrapper-radius: 10px;
  --select-border: #333;
  --label-color: #888;
  --turn-color: #aaa;
  --active-turn-bg: rgba(79, 195, 247, 0.1);
  --btn-color: #111;
  --win-bg: rgba(79, 195, 247, 0.15);
  --pass-bg: rgba(255, 193, 7, 0.15);
  --pass-color: #ffc107;
  --board-shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
  --black-disc-shadow: inset 0 -3px 6px rgba(255, 255, 255, 0.08), 0 2px 6px rgba(0, 0, 0, 0.5);
  --white-disc-shadow: inset 0 -3px 6px rgba(0, 0, 0, 0.08), 0 2px 6px rgba(0, 0, 0, 0.5);
  --black-icon-shadow: inset 0 -2px 4px rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.4);
  --white-icon-shadow: inset 0 -2px 4px rgba(0, 0, 0, 0.1), 0 1px 3px rgba(0, 0, 0, 0.4);
  --cell-gap: 1.5px;
  --disc-size: 80%;
  --title-weight: 700;
  --title-spacing: 0.05em;
}

/* ===== 8-Bit Retro Theme ===== */

[data-theme="retro"] {
  --board-bg: #306230;
  --board-border: #0f380f;
  --cell-border: #0f380f;
  --bg: #0f380f;
  --surface: #306230;
  --text: #8bac0f;
  --accent: #9bbc0f;
  --black-disc: #0f380f;
  --white-disc: #9bbc0f;
  --valid-hint: rgba(155, 188, 15, 0.4);
  --font-family: 'Press Start 2P', monospace;
  --disc-radius: 4px;
  --cell-radius: 0px;
  --board-radius: 0px;
  --board-wrapper-radius: 0px;
  --select-border: #8bac0f;
  --label-color: #8bac0f;
  --turn-color: #8bac0f;
  --active-turn-bg: rgba(155, 188, 15, 0.2);
  --btn-color: #0f380f;
  --win-bg: rgba(155, 188, 15, 0.2);
  --pass-bg: rgba(155, 188, 15, 0.15);
  --pass-color: #9bbc0f;
  --board-shadow: 6px 6px 0 #0a2a0a;
  --black-disc-shadow: 2px 2px 0 rgba(0, 0, 0, 0.5);
  --white-disc-shadow: 2px 2px 0 rgba(0, 0, 0, 0.3);
  --black-icon-shadow: 2px 2px 0 rgba(0, 0, 0, 0.5);
  --white-icon-shadow: 2px 2px 0 rgba(0, 0, 0, 0.3);
  --cell-gap: 2px;
  --disc-size: 70%;
  --title-weight: 400;
  --title-spacing: 0.1em;
}

/* ===== Futuristic Theme ===== */

[data-theme="futuristic"] {
  --board-bg: #0a0a1a;
  --board-border: #1a0a3a;
  --cell-border: #2a1a4a;
  --bg: #050510;
  --surface: #0d0d25;
  --text: #e0e8ff;
  --accent: #00f0ff;
  --black-disc: #1a0a3a;
  --white-disc: #e0e8ff;
  --valid-hint: rgba(0, 240, 255, 0.3);
  --font-family: 'Orbitron', sans-serif;
  --disc-radius: 50%;
  --cell-radius: 2px;
  --board-radius: 4px;
  --board-wrapper-radius: 6px;
  --select-border: #00f0ff44;
  --label-color: #00f0ff99;
  --turn-color: #00f0ffaa;
  --active-turn-bg: rgba(0, 240, 255, 0.08);
  --btn-color: #050510;
  --win-bg: rgba(0, 240, 255, 0.1);
  --pass-bg: rgba(255, 0, 200, 0.12);
  --pass-color: #ff00c8;
  --board-shadow: 0 0 30px rgba(0, 240, 255, 0.15), 0 0 60px rgba(0, 240, 255, 0.05);
  --black-disc-shadow: 0 0 8px rgba(120, 0, 255, 0.6), inset 0 0 6px rgba(120, 0, 255, 0.3);
  --white-disc-shadow: 0 0 8px rgba(0, 240, 255, 0.5), inset 0 0 6px rgba(0, 240, 255, 0.2);
  --black-icon-shadow: 0 0 6px rgba(120, 0, 255, 0.6);
  --white-icon-shadow: 0 0 6px rgba(0, 240, 255, 0.5);
  --cell-gap: 1px;
  --disc-size: 76%;
  --title-weight: 900;
  --title-spacing: 0.15em;
}

/* ===== Shrek Theme ===== */

[data-theme="shrek"] {
  --board-bg: #3b5a1e;
  --board-border: #2a4010;
  --cell-border: #4a6b2a;
  --bg: #1a2e0a;
  --surface: #2a3f15;
  --text: #e8e0c8;
  --accent: #7cc832;
  --black-disc: #3d2b1a;
  --white-disc: #f5e6c8;
  --valid-hint: rgba(124, 200, 50, 0.35);
  --font-family: 'Boogaloo', 'Comic Sans MS', cursive, sans-serif;
  --disc-radius: 50%;
  --cell-radius: 3px;
  --board-radius: 14px;
  --board-wrapper-radius: 16px;
  --select-border: #5a8030;
  --label-color: #a0c070;
  --turn-color: #c8daa0;
  --active-turn-bg: rgba(124, 200, 50, 0.15);
  --btn-color: #1a2e0a;
  --win-bg: rgba(124, 200, 50, 0.2);
  --pass-bg: rgba(200, 160, 60, 0.2);
  --pass-color: #daa520;
  --board-shadow: 0 6px 24px rgba(30, 50, 10, 0.7), inset 0 0 40px rgba(0, 0, 0, 0.08);
  --black-disc-shadow: inset 0 -3px 6px rgba(0, 0, 0, 0.3), 0 2px 8px rgba(30, 50, 10, 0.5);
  --white-disc-shadow: inset 0 -3px 6px rgba(100, 60, 20, 0.15), 0 2px 8px rgba(30, 50, 10, 0.4);
  --black-icon-shadow: inset 0 -2px 4px rgba(0, 0, 0, 0.3), 0 1px 4px rgba(30, 50, 10, 0.5);
  --white-icon-shadow: inset 0 -2px 4px rgba(100, 60, 20, 0.15), 0 1px 4px rgba(30, 50, 10, 0.4);
  --cell-gap: 2px;
  --disc-size: 78%;
  --title-weight: 400;
  --title-spacing: 0.03em;
}

/* ===== Cat in the Hat Theme ===== */

[data-theme="cat"] {
  --board-bg: #ffffff;
  --board-border: #d81e1e;
  --cell-border: #e8b3b3;
  --bg: #fff8f0;
  --surface: #ffeaea;
  --text: #1a1a1a;
  --accent: #d81e1e;
  --black-disc: #1a1a1a;
  --white-disc: #ffffff;
  --valid-hint: rgba(216, 30, 30, 0.25);
  --font-family: 'Fredoka One', 'Comic Sans MS', cursive, sans-serif;
  --disc-radius: 50%;
  --cell-radius: 0px;
  --board-radius: 8px;
  --board-wrapper-radius: 12px;
  --select-border: #d81e1e;
  --label-color: #d81e1e;
  --turn-color: #d81e1e;
  --active-turn-bg: rgba(216, 30, 30, 0.12);
  --btn-color: #ffffff;
  --win-bg: rgba(216, 30, 30, 0.15);
  --pass-bg: rgba(255, 200, 40, 0.2);
  --pass-color: #c89020;
  --board-shadow: 0 6px 20px rgba(216, 30, 30, 0.3), 0 0 0 4px #1a1a1a;
  --black-disc-shadow: inset 0 -3px 6px rgba(255, 255, 255, 0.1), 0 2px 6px rgba(0, 0, 0, 0.5);
  --white-disc-shadow: inset 0 -3px 6px rgba(0, 0, 0, 0.1), 0 2px 6px rgba(216, 30, 30, 0.4);
  --black-icon-shadow: inset 0 -2px 4px rgba(255, 255, 255, 0.1), 0 1px 3px rgba(0, 0, 0, 0.4);
  --white-icon-shadow: inset 0 -2px 4px rgba(0, 0, 0, 0.1), 0 1px 3px rgba(216, 30, 30, 0.4);
  --cell-gap: 2px;
  --disc-size: 78%;
  --title-weight: 400;
  --title-spacing: 0.05em;
}

#reversi-screen {
  font-family: var(--font-family);
  background: var(--bg);
  color: var(--text);
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 1rem;
  border-radius: 10px;
  transition: background 0.4s, color 0.4s;
}

#reversi-screen.hidden { display: none; }

#app {
  width: 100%;
  max-width: 560px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  margin: 0 auto;
}

header {
  width: 100%;
  text-align: center;
}

h1 {
  font-size: 2rem;
  font-weight: var(--title-weight);
  letter-spacing: var(--title-spacing);
  color: var(--accent);
  margin-bottom: 0.75rem;
  transition: color 0.4s;
}

#controls {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  align-items: flex-end;
  flex-wrap: wrap;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
}

.control-group label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--label-color);
}

select {
  background: var(--surface);
  color: var(--text);
  border: 1px solid var(--select-border);
  border-radius: 6px;
  padding: 0.4rem 0.6rem;
  font-size: 0.85rem;
  font-family: inherit;
  cursor: pointer;
  outline: none;
  transition: background 0.3s, border-color 0.3s;
}

select:focus {
  border-color: var(--accent);
}

#new-game-btn {
  background: var(--accent);
  color: var(--btn-color);
  border: none;
  border-radius: 6px;
  padding: 0.45rem 1.2rem;
  font-size: 0.85rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: opacity 0.15s, background 0.3s;
}

#new-game-btn:hover {
  opacity: 0.85;
}

#game-container {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
}

/* Scoreboard */

#scoreboard {
  width: 100%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: var(--surface);
  border-radius: 10px;
  padding: 0.6rem 1rem;
  transition: background 0.3s;
}

.score-card {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.disc-icon {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  flex-shrink: 0;
}

.disc-icon.small {
  width: 18px;
  height: 18px;
}

.disc-icon.black {
  background: var(--black-disc);
  box-shadow: var(--black-icon-shadow);
  border-radius: var(--disc-radius);
}

.disc-icon.white {
  background: var(--white-disc);
  box-shadow: var(--white-icon-shadow);
  border-radius: var(--disc-radius);
}

.score-info {
  display: flex;
  flex-direction: column;
}

.player-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--label-color);
}

.score-value {
  font-size: 1.4rem;
  font-weight: 700;
  line-height: 1;
}

#turn-indicator {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.85rem;
  color: var(--turn-color);
}

.score-card.active-turn {
  background: var(--active-turn-bg);
  border-radius: 8px;
  padding: 0.3rem 0.5rem;
  margin: -0.3rem -0.5rem;
}

/* Board */

#board-wrapper {
  width: 100%;
  aspect-ratio: 1;
  max-width: 480px;
  padding: 6px;
  background: var(--board-border);
  border-radius: var(--board-wrapper-radius);
  box-shadow: var(--board-shadow);
  transition: background 0.3s, box-shadow 0.4s;
}

#board {
  width: 100%;
  height: 100%;
  display: grid;
  grid-template-columns: repeat(8, 1fr);
  grid-template-rows: repeat(8, 1fr);
  gap: var(--cell-gap);
  background: var(--cell-border);
  border-radius: var(--board-radius);
  overflow: hidden;
  transition: background 0.3s;
}

.cell {
  background: var(--board-bg);
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: default;
  position: relative;
  border-radius: var(--cell-radius);
  transition: background 0.3s;
}

.cell.valid {
  cursor: pointer;
}

.cell.valid::after {
  content: '';
  width: 35%;
  height: 35%;
  border-radius: 50%;
  background: var(--valid-hint);
  pointer-events: none;
  animation: pulse 1.8s ease-in-out infinite;
  /* Sync all hints to the same timeline so hover can't desync them */
  animation-delay: calc(-1 * var(--pulse-offset, 0s));
}

.cell.valid:hover::after {
  width: 80%;
  height: 80%;
  background: rgba(255, 255, 255, 0.18);
  /* Keep animation running so it stays in sync — just override opacity */
  opacity: 1;
}

@keyframes pulse {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 1; }
}

/* Discs */

.disc {
  width: var(--disc-size);
  height: var(--disc-size);
  border-radius: var(--disc-radius);
  position: absolute;
  transition: transform 0.4s ease;
  transform-style: preserve-3d;
}

.disc.black {
  background: var(--black-disc);
  box-shadow: var(--black-disc-shadow);
}

.disc.white {
  background: var(--white-disc);
  box-shadow: var(--white-disc-shadow);
}

.disc.placed {
  animation: pop-in 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes pop-in {
  0% { transform: scale(0); }
  100% { transform: scale(1); }
}

.disc.flipping {
  animation: flip 0.5s ease-in-out;
}

@keyframes flip {
  0% { transform: rotateY(0deg) scale(1); }
  50% { transform: rotateY(90deg) scale(1.1); }
  100% { transform: rotateY(180deg) scale(1); }
}

/* Last move marker */
.disc.last-move::after {
  content: '';
  position: absolute;
  width: 20%;
  height: 20%;
  border-radius: 50%;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
}

.disc.black.last-move::after {
  background: rgba(255, 255, 255, 0.3);
}

.disc.white.last-move::after {
  background: rgba(0, 0, 0, 0.2);
}

/* Vanishing disc */

.disc.vanishing {
  animation: vanish-out 0.4s ease-out forwards !important;
}

@keyframes vanish-out {
  0% { transform: scale(1); opacity: 1; }
  100% { transform: scale(0); opacity: 0; }
}

/* Powerup icon */

.powerup-icon {
  position: absolute;
  font-size: 1.4em;
  z-index: 2;
  animation: powerup-bob 1.5s ease-in-out infinite;
  pointer-events: none;
  filter: drop-shadow(0 0 6px rgba(255, 200, 0, 0.7));
  line-height: 1;
}

@keyframes powerup-bob {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-10%) scale(1.1); }
}

.powerup-icon.collected {
  animation: powerup-collect 0.45s ease-out forwards !important;
}

@keyframes powerup-collect {
  0% { transform: scale(1); opacity: 1; }
  40% { transform: scale(1.6); opacity: 0.9; }
  100% { transform: scale(0); opacity: 0; }
}

.cell.has-powerup {
  background: radial-gradient(circle, rgba(255, 200, 0, 0.12) 0%, var(--board-bg) 70%);
}

/* Message bar */

#message-bar {
  width: 100%;
  text-align: center;
  padding: 0.6rem 1rem;
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  background: var(--surface);
  transition: opacity 0.3s;
}

#message-bar.hidden {
  display: none;
}

#message-bar.win {
  background: var(--win-bg);
  color: var(--accent);
}

#message-bar.pass {
  background: var(--pass-bg);
  color: var(--pass-color);
}

#message-bar.powerup {
  background: rgba(255, 200, 0, 0.15);
  color: #ffd700;
}

/* ===== 8-Bit Theme Overrides ===== */

[data-theme="retro"] body {
  image-rendering: pixelated;
}

[data-theme="retro"] h1 {
  font-size: 1.3rem;
  text-shadow: 3px 3px 0 #0f380f;
}

[data-theme="retro"] select,
[data-theme="retro"] #new-game-btn {
  border-radius: 0;
  font-size: 0.65rem;
}

[data-theme="retro"] #new-game-btn {
  border: 2px solid #0f380f;
  text-transform: uppercase;
}

[data-theme="retro"] #scoreboard {
  border-radius: 0;
  border: 2px solid #8bac0f;
}

[data-theme="retro"] .score-value {
  font-size: 1.1rem;
}

[data-theme="retro"] #turn-indicator {
  font-size: 0.6rem;
}

[data-theme="retro"] .player-label,
[data-theme="retro"] .control-group label {
  font-size: 0.5rem;
}

[data-theme="retro"] #board-wrapper {
  border: 3px solid #8bac0f;
  padding: 4px;
}

[data-theme="retro"] .cell.valid::after {
  border-radius: 2px;
  animation: retro-blink 0.8s steps(1) infinite;
}

[data-theme="retro"] .cell.valid:hover::after {
  opacity: 1;
}

[data-theme="retro"] .disc.placed {
  animation: retro-pop 0.2s steps(3);
}

[data-theme="retro"] .disc.flipping {
  animation: retro-flip 0.3s steps(4);
}

[data-theme="retro"] #message-bar {
  border-radius: 0;
  border: 2px solid #8bac0f;
  font-size: 0.65rem;
}

[data-theme="retro"] .disc-icon {
  border-radius: 4px;
}

[data-theme="retro"] .score-card.active-turn {
  border-radius: 0;
  outline: 2px dashed #9bbc0f;
  background: transparent;
}

[data-theme="retro"] .powerup-icon {
  animation: retro-blink 0.8s steps(1) infinite;
  filter: none;
  font-size: 1.1em;
}

[data-theme="retro"] .cell.has-powerup {
  background: var(--board-bg);
  outline: 2px dashed #9bbc0f;
  outline-offset: -2px;
}

[data-theme="retro"] #message-bar.powerup {
  background: rgba(155, 188, 15, 0.2);
  color: #9bbc0f;
}

@keyframes retro-blink {
  0%, 49% { opacity: 1; }
  50%, 100% { opacity: 0; }
}

@keyframes retro-pop {
  0% { transform: scale(0); }
  33% { transform: scale(0.5); }
  66% { transform: scale(1.1); }
  100% { transform: scale(1); }
}

@keyframes retro-flip {
  0% { transform: scaleX(1); }
  25% { transform: scaleX(0.5); }
  50% { transform: scaleX(0); }
  75% { transform: scaleX(0.5); }
  100% { transform: scaleX(1); }
}

/* ===== Futuristic Theme Overrides ===== */

[data-theme="retro"] .disc.vanishing {
  animation: retro-vanish 0.3s steps(3) forwards !important;
}

@keyframes retro-vanish {
  0% { transform: scale(1); opacity: 1; }
  33% { transform: scale(0.6); opacity: 0.5; }
  66% { transform: scale(0.3); opacity: 0.2; }
  100% { transform: scale(0); opacity: 0; }
}

[data-theme="futuristic"] .disc.vanishing {
  animation: neon-vanish 0.5s ease-out forwards !important;
}

@keyframes neon-vanish {
  0% { transform: scale(1); opacity: 1; filter: brightness(1); }
  50% { transform: scale(1.2); opacity: 0.7; filter: brightness(3); }
  100% { transform: scale(0); opacity: 0; filter: brightness(0); }
}

[data-theme="futuristic"] body {
  background: var(--bg);
  background-image:
    radial-gradient(ellipse at 20% 50%, rgba(0, 100, 255, 0.06) 0%, transparent 50%),
    radial-gradient(ellipse at 80% 50%, rgba(120, 0, 255, 0.06) 0%, transparent 50%);
}

[data-theme="futuristic"] h1 {
  font-size: 1.6rem;
  text-shadow: 0 0 20px rgba(0, 240, 255, 0.5), 0 0 40px rgba(0, 240, 255, 0.2);
}

[data-theme="futuristic"] select {
  border-radius: 3px;
  background: rgba(13, 13, 37, 0.8);
  border: 1px solid rgba(0, 240, 255, 0.3);
  font-size: 0.75rem;
}

[data-theme="futuristic"] select:focus {
  box-shadow: 0 0 8px rgba(0, 240, 255, 0.3);
}

[data-theme="futuristic"] #new-game-btn {
  border-radius: 3px;
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  box-shadow: 0 0 12px rgba(0, 240, 255, 0.3);
}

[data-theme="futuristic"] #new-game-btn:hover {
  box-shadow: 0 0 20px rgba(0, 240, 255, 0.5);
}

[data-theme="futuristic"] #scoreboard {
  border-radius: 4px;
  border: 1px solid rgba(0, 240, 255, 0.15);
  background: rgba(13, 13, 37, 0.7);
  backdrop-filter: blur(8px);
}

[data-theme="futuristic"] .score-value {
  color: var(--accent);
  text-shadow: 0 0 8px rgba(0, 240, 255, 0.4);
}

[data-theme="futuristic"] #board-wrapper {
  border: 1px solid rgba(0, 240, 255, 0.2);
  background: linear-gradient(135deg, #1a0a3a, #0d0d25);
}

[data-theme="futuristic"] .cell {
  background: var(--board-bg);
  border: 1px solid rgba(0, 240, 255, 0.06);
}

[data-theme="futuristic"] .cell.valid::after {
  background: var(--valid-hint);
  box-shadow: 0 0 8px rgba(0, 240, 255, 0.4);
  animation: neon-pulse 1.5s ease-in-out infinite;
}

[data-theme="futuristic"] .cell.valid:hover::after {
  box-shadow: 0 0 15px rgba(0, 240, 255, 0.6);
  opacity: 1;
}

[data-theme="futuristic"] .disc.black {
  background: radial-gradient(circle at 35% 35%, #3a1a6a, #1a0a3a);
}

[data-theme="futuristic"] .disc.white {
  background: radial-gradient(circle at 35% 35%, #ffffff, #c0d8ff);
}

[data-theme="futuristic"] .disc.placed {
  animation: neon-pop 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

[data-theme="futuristic"] .disc.last-move::after {
  box-shadow: 0 0 4px rgba(0, 240, 255, 0.6);
}

[data-theme="futuristic"] #message-bar {
  border-radius: 4px;
  border: 1px solid rgba(0, 240, 255, 0.15);
  backdrop-filter: blur(8px);
  text-shadow: 0 0 10px currentColor;
}

[data-theme="futuristic"] .score-card.active-turn {
  border-radius: 4px;
  box-shadow: 0 0 10px rgba(0, 240, 255, 0.15);
}

[data-theme="futuristic"] .powerup-icon {
  filter: drop-shadow(0 0 10px rgba(0, 240, 255, 0.8)) drop-shadow(0 0 20px rgba(120, 0, 255, 0.4));
}

[data-theme="futuristic"] .cell.has-powerup {
  background: radial-gradient(circle, rgba(0, 240, 255, 0.08) 0%, var(--board-bg) 70%);
  box-shadow: inset 0 0 12px rgba(0, 240, 255, 0.1);
}

[data-theme="futuristic"] .powerup-icon.collected {
  animation: neon-collect 0.5s ease-out forwards !important;
}

@keyframes neon-collect {
  0% { transform: scale(1); opacity: 1; filter: brightness(1); }
  40% { transform: scale(1.8); opacity: 0.9; filter: brightness(3); }
  100% { transform: scale(0); opacity: 0; filter: brightness(0); }
}

[data-theme="futuristic"] #message-bar.powerup {
  background: rgba(0, 240, 255, 0.1);
  color: #00f0ff;
  text-shadow: 0 0 10px rgba(0, 240, 255, 0.5);
}

@keyframes neon-pulse {
  0%, 100% { opacity: 0.4; box-shadow: 0 0 6px rgba(0, 240, 255, 0.3); }
  50% { opacity: 1; box-shadow: 0 0 14px rgba(0, 240, 255, 0.6); }
}

@keyframes neon-pop {
  0% { transform: scale(0); filter: brightness(2); }
  60% { transform: scale(1.1); filter: brightness(1.5); }
  100% { transform: scale(1); filter: brightness(1); }
}

/* Scanline overlay for futuristic theme */
[data-theme="futuristic"] #board::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: repeating-linear-gradient(
    0deg,
    transparent,
    transparent 2px,
    rgba(0, 240, 255, 0.015) 2px,
    rgba(0, 240, 255, 0.015) 4px
  );
  pointer-events: none;
  z-index: 1;
}

[data-theme="futuristic"] #board {
  position: relative;
}

/* ===== Variant-Specific Styles ===== */

/* Wall / Obstacle cells */
.cell.wall {
  background: #1a1a1a;
  cursor: default;
  background-image: repeating-linear-gradient(
    45deg, transparent, transparent 4px, rgba(255,255,255,0.04) 4px, rgba(255,255,255,0.04) 8px
  );
}

[data-theme="retro"] .cell.wall {
  background: #0a2a0a;
  background-image: none;
}

[data-theme="futuristic"] .cell.wall {
  background: #060612;
  background-image: repeating-linear-gradient(
    45deg, transparent, transparent 3px, rgba(0,240,255,0.03) 3px, rgba(0,240,255,0.03) 6px
  );
}

/* Fog of War overlay */
.cell.fogged {
  background: #0d0d0d !important;
}

.cell.fogged .disc {
  visibility: hidden;
}

.cell.fogged .powerup-icon {
  visibility: hidden;
}

[data-theme="retro"] .cell.fogged {
  background: #071a07 !important;
}

[data-theme="futuristic"] .cell.fogged {
  background: #030308 !important;
}

/* Shrinking — locked ring cells use .wall */
.cell.shrink-warn {
  animation: shrink-flash 1s ease-in-out 3;
}

@keyframes shrink-flash {
  0%, 100% { background: var(--board-bg); }
  50% { background: rgba(255, 80, 80, 0.25); }
}

/* King of the Hill — center highlight */
.cell.koth-center {
  background: rgba(255, 215, 0, 0.12);
  box-shadow: inset 0 0 8px rgba(255, 215, 0, 0.1);
}

[data-theme="retro"] .cell.koth-center {
  outline: 1px dashed #9bbc0f;
  outline-offset: -1px;
  background: var(--board-bg);
}

[data-theme="futuristic"] .cell.koth-center {
  background: rgba(0, 240, 255, 0.06);
  box-shadow: inset 0 0 10px rgba(0, 240, 255, 0.08);
}

/* Thieves — stealable disc indicator */
.cell.stealable {
  cursor: pointer;
}

.cell.stealable .disc {
  outline: 2px dashed var(--accent);
  outline-offset: 1px;
  animation: steal-pulse 1.2s ease-in-out infinite;
}

@keyframes steal-pulse {
  0%, 100% { outline-color: var(--accent); }
  50% { outline-color: transparent; }
}

[data-theme="retro"] .cell.stealable .disc {
  outline-style: solid;
  outline-color: #9bbc0f;
  animation: retro-blink 0.8s steps(1) infinite;
}

/* Plague infection flash */
.disc.infected {
  animation: infect-flash 0.6s ease-out !important;
}

@keyframes infect-flash {
  0% { filter: brightness(1); }
  30% { filter: brightness(2) hue-rotate(60deg); }
  100% { filter: brightness(1); }
}

[data-theme="retro"] .disc.infected {
  animation: retro-flip 0.3s steps(4) !important;
}

[data-theme="futuristic"] .disc.infected {
  animation: neon-infect 0.6s ease-out !important;
}

@keyframes neon-infect {
  0% { filter: brightness(1); box-shadow: var(--black-disc-shadow); }
  30% { filter: brightness(3); box-shadow: 0 0 15px rgba(255, 0, 200, 0.8); }
  100% { filter: brightness(1); }
}

/* Timer display */
.timer-value {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

.timer-value.hidden {
  display: none;
}

.timer-value.low-time {
  color: #ff4444;
  animation: timer-warn 0.5s steps(1) infinite;
}

@keyframes timer-warn {
  0%, 49% { opacity: 1; }
  50%, 100% { opacity: 0.4; }
}

/* Speed countdown */
#message-bar.speed-warn {
  background: rgba(255, 100, 0, 0.15);
  color: #ff6400;
}

/* Cascade chain flash */
.disc.cascade-flip {
  animation: cascade-flash 0.4s ease-out !important;
}

@keyframes cascade-flash {
  0% { filter: brightness(1); transform: scale(1); }
  40% { filter: brightness(1.8); transform: scale(1.15); }
  100% { filter: brightness(1); transform: scale(1); }
}

/* Responsive */

@media (max-width: 400px) {
  body { padding: 0.5rem; }
  h1 { font-size: 1.5rem; }
  #scoreboard { padding: 0.4rem 0.6rem; }
  .disc-icon { width: 22px; height: 22px; }
  .score-value { font-size: 1.1rem; }
  [data-theme="retro"] h1 { font-size: 1rem; }
  [data-theme="futuristic"] h1 { font-size: 1.2rem; }
}


/* === Online Lobby === */
#lobby-overlay {
  position: fixed; inset: 0;
  background: rgba(0,0,0,0.65);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000;
  backdrop-filter: blur(6px);
}
#lobby-overlay.hidden { display: none; }
.lobby-card {
  background: var(--surface, #fff);
  color: var(--text, #111);
  border-radius: 12px;
  padding: 28px 32px;
  max-width: 440px;
  width: calc(100% - 32px);
  box-shadow: 0 20px 60px rgba(0,0,0,0.5);
  border: 1px solid var(--cell-border, #d0d0d0);
}
.lobby-card h2 { margin-top: 0; margin-bottom: 16px; }
.lobby-card p { margin: 8px 0; line-height: 1.45; }
.lobby-buttons {
  display: flex; gap: 10px; justify-content: center;
  margin: 16px 0 8px;
  flex-wrap: wrap;
}
.lobby-card button {
  background: var(--accent, #2a7);
  color: #fff;
  border: 0;
  padding: 10px 18px;
  font: inherit;
  font-weight: 600;
  border-radius: 6px;
  cursor: pointer;
}
.lobby-card button:hover { filter: brightness(1.1); }
.lobby-card button:disabled { opacity: 0.5; cursor: not-allowed; }
.lobby-card .lobby-link {
  background: transparent;
  color: var(--label-color, #888);
  font-weight: normal;
  padding: 6px 12px;
  display: block;
  margin: 12px auto 0;
}
.lobby-card .lobby-link:hover { color: var(--text, #111); }
.peer-id-row {
  display: flex; gap: 8px; align-items: center;
  margin: 10px 0; flex-wrap: wrap;
}
.peer-id-row code {
  flex: 1;
  background: rgba(0,0,0,0.08);
  padding: 10px 12px;
  border-radius: 6px;
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 0.95em;
  word-break: break-all;
  min-width: 0;
}
.peer-id-row button { flex-shrink: 0; }
#lobby-join-input {
  width: 100%;
  padding: 10px 12px;
  font-family: ui-monospace, Menlo, Consolas, monospace;
  font-size: 1em;
  border: 1px solid var(--select-border, #ccc);
  border-radius: 6px;
  box-sizing: border-box;
  margin: 6px 0;
  background: rgba(0,0,0,0.04);
  color: inherit;
}
.lobby-status {
  font-size: 0.9em;
  color: var(--label-color, #888);
  min-height: 1.2em;
}
.lobby-status.error { color: #d44; }
.lobby-status.success { color: #2a7; }

#net-status {
  font-size: 0.85em;
  text-align: center;
  padding: 6px 10px;
  margin-top: 6px;
  border-radius: 4px;
  background: rgba(42, 119, 40, 0.12);
  color: var(--text, #111);
}
#net-status.hidden { display: none; }
#net-status.disconnected { background: rgba(200, 60, 60, 0.15); color: #d44; }

[data-theme="retro"] .lobby-card {
  font-family: "Press Start 2P", monospace;
  font-size: 0.8em;
  border-radius: 0;
  border: 3px solid #000;
}
[data-theme="retro"] .lobby-card button { border-radius: 0; }
[data-theme="futuristic"] .lobby-card {
  background: rgba(10, 20, 40, 0.95);
  color: #eaf;
  border: 1px solid #3af;
  box-shadow: 0 0 30px rgba(60, 160, 255, 0.4);
}
[data-theme="futuristic"] .lobby-card button {
  background: linear-gradient(135deg, #3af, #63f);
}

/* Shrek theme extras */
[data-theme="shrek"] #reversi-screen {
  background: linear-gradient(180deg, #1a2e0a 0%, #0f1f06 40%, #1a1508 100%);
}
[data-theme="shrek"] h1 {
  color: #7cc832;
  text-shadow: 2px 3px 0 #2a4010, 0 0 20px rgba(124, 200, 50, 0.3);
}
[data-theme="shrek"] #board-wrapper {
  background: radial-gradient(ellipse at center, #4a6b2a 0%, #2a4010 70%);
  border: 3px solid #5a7a30;
  box-shadow: 0 6px 24px rgba(30, 50, 10, 0.7), 0 0 60px rgba(80, 140, 30, 0.12);
}
[data-theme="shrek"] #board {
  background: repeating-conic-gradient(#3b5a1e 0% 25%, #35521a 25% 50%) 0 0 / calc(100% / 4) calc(100% / 4);
}
[data-theme="shrek"] .cell {
  border-color: #4a6b2a;
}
[data-theme="shrek"] .cell:hover {
  background: rgba(124, 200, 50, 0.18);
}
[data-theme="shrek"] .disc.black {
  background: radial-gradient(circle at 35% 35%, #5c3d1e, #3d2b1a 70%);
}
[data-theme="shrek"] .disc.white {
  background: radial-gradient(circle at 35% 35%, #fff8e8, #f5e6c8 70%);
}
[data-theme="shrek"] button#new-game-btn {
  background: linear-gradient(135deg, #7cc832, #5a9a20);
  border: 2px solid #4a7a18;
  text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}
[data-theme="shrek"] button#new-game-btn:hover {
  background: linear-gradient(135deg, #8dd83e, #6ab828);
  box-shadow: 0 0 16px rgba(124, 200, 50, 0.4);
}
[data-theme="shrek"] select {
  background: #2a3f15;
  border-color: #5a8030;
  color: #e8e0c8;
}
[data-theme="shrek"] .score-card {
  border-color: #4a6b2a;
}
[data-theme="shrek"] #message-bar {
  border-color: #5a8030;
}
[data-theme="shrek"] .lobby-card {
  background: rgba(42, 63, 21, 0.97);
  color: #e8e0c8;
  border: 2px solid #5a8030;
  box-shadow: 0 20px 60px rgba(20, 40, 5, 0.7), 0 0 40px rgba(80, 140, 30, 0.1);
}
[data-theme="shrek"] .lobby-card button {
  background: linear-gradient(135deg, #7cc832, #5a9a20);
  border: 1px solid #4a7a18;
}
[data-theme="shrek"] .peer-id-row code {
  background: rgba(0, 0, 0, 0.25);
  color: #c8daa0;
}
[data-theme="shrek"] #lobby-join-input {
  background: rgba(0, 0, 0, 0.2);
  border-color: #5a8030;
  color: #e8e0c8;
}

/* Cat in the Hat theme extras */
[data-theme="cat"] #reversi-screen {
  background:
    repeating-linear-gradient(
      45deg,
      #fff8f0 0px,
      #fff8f0 40px,
      #ffe0e0 40px,
      #ffe0e0 80px
    );
}
[data-theme="cat"] h1 {
  color: #d81e1e;
  text-shadow: 3px 3px 0 #1a1a1a, 6px 6px 0 rgba(216, 30, 30, 0.2);
  font-size: 2.6rem;
}
[data-theme="cat"] h1::before { content: "🎩 "; }
[data-theme="cat"] h1::after  { content: " 🐱"; }
[data-theme="cat"] #board-wrapper {
  background: #ffffff;
  border: 4px solid #1a1a1a;
  box-shadow: 0 6px 20px rgba(216, 30, 30, 0.3), 8px 8px 0 #1a1a1a;
}
[data-theme="cat"] #board {
  background:
    repeating-linear-gradient(
      0deg,
      #ffffff 0,
      #ffffff calc(100% / 8),
      #ffe5e5 calc(100% / 8),
      #ffe5e5 calc(200% / 8)
    );
}
[data-theme="cat"] .cell {
  border-color: rgba(216, 30, 30, 0.25);
}
[data-theme="cat"] .cell:hover {
  background: rgba(216, 30, 30, 0.1);
}
[data-theme="cat"] .disc.black {
  background: radial-gradient(circle at 35% 35%, #3a3a3a, #000 70%);
}
[data-theme="cat"] .disc.white {
  background: radial-gradient(circle at 35% 35%, #fff, #fff 60%, #ffcccc 100%);
  border: 2px solid #d81e1e;
}
[data-theme="cat"] .disc-icon.black {
  background: radial-gradient(circle at 35% 35%, #3a3a3a, #000 70%);
}
[data-theme="cat"] .disc-icon.white {
  background: #fff;
  border: 2px solid #d81e1e;
}
[data-theme="cat"] button#new-game-btn {
  background: #d81e1e;
  color: #fff;
  border: 3px solid #1a1a1a;
  text-shadow: 1px 1px 0 #1a1a1a;
  box-shadow: 3px 3px 0 #1a1a1a;
}
[data-theme="cat"] button#new-game-btn:hover {
  background: #ff3030;
  transform: translate(-1px, -1px);
  box-shadow: 4px 4px 0 #1a1a1a;
}
[data-theme="cat"] select {
  background: #ffffff;
  border: 2px solid #d81e1e;
  color: #1a1a1a;
  font-weight: normal;
}
[data-theme="cat"] label {
  color: #d81e1e;
  font-weight: normal;
}
[data-theme="cat"] .score-card {
  background: #ffffff;
  border: 2px solid #1a1a1a;
  box-shadow: 3px 3px 0 #d81e1e;
}
[data-theme="cat"] #scoreboard {
  background: transparent;
}
[data-theme="cat"] #turn-indicator {
  color: #1a1a1a;
}
[data-theme="cat"] #message-bar {
  background: #fff;
  border: 3px solid #d81e1e;
  color: #1a1a1a;
  box-shadow: 4px 4px 0 #1a1a1a;
}
[data-theme="cat"] .valid::before {
  background: rgba(216, 30, 30, 0.45);
}
[data-theme="cat"] .lobby-card {
  background: #ffffff;
  color: #1a1a1a;
  border: 4px solid #1a1a1a;
  box-shadow: 8px 8px 0 #d81e1e;
  border-radius: 8px;
}
[data-theme="cat"] .lobby-card h2 {
  color: #d81e1e;
  text-shadow: 2px 2px 0 #1a1a1a;
}
[data-theme="cat"] .lobby-card button {
  background: #d81e1e;
  color: #fff;
  border: 2px solid #1a1a1a;
  box-shadow: 3px 3px 0 #1a1a1a;
}
[data-theme="cat"] .lobby-card button:hover {
  background: #ff3030;
}
[data-theme="cat"] .lobby-card .lobby-link {
  background: transparent;
  box-shadow: none;
  border: 0;
  color: #888;
}
[data-theme="cat"] .peer-id-row code {
  background: #fff0f0;
  color: #1a1a1a;
  border: 2px dashed #d81e1e;
}
[data-theme="cat"] #lobby-join-input {
  background: #fff;
  border: 2px solid #d81e1e;
  color: #1a1a1a;
}