/* ═══════════════════════════════════════════════════════════════════
   TIC TAC TOE — NEON ARENA  •  Premium Design System v2
   ═══════════════════════════════════════════════════════════════════
   Features:
   • Neon glassmorphism design language
   • CSS custom-property theme engine (dark / light / neon)
   • Layered glow & shadow depth system
   • Smooth micro-interactions & keyframe animations
   • Mobile-first responsive layout
   • Full keyboard-focus & accessibility states
   ═══════════════════════════════════════════════════════════════════ */

/* ─────────────────── Design Tokens ─────────────────── */
:root {
  /* Colours */
  --bg-primary: #06060f;
  --bg-secondary: #0c0c1e;
  --bg-card: rgba(255, 255, 255, 0.035);
  --bg-card-solid: #10102a;
  --text-primary: #e8ecf1;
  --text-secondary: #8892a4;
  --text-muted: #555e70;
  --accent: #00e5ff;
  --accent-rgb: 0, 229, 255;
  --accent-secondary: #ff006e;
  --accent-sec-rgb: 255, 0, 110;
  --accent-tertiary: #a855f7;
  --gold: #ffd700;
  --gold-rgb: 255, 215, 0;
  --cell-bg: rgba(255, 255, 255, 0.03);
  --cell-hover: rgba(var(--accent-rgb), 0.1);
  --border-glow: rgba(var(--accent-rgb), 0.2);
  --popup-bg: rgba(8, 8, 22, 0.94);
  --overlay: rgba(0, 0, 0, 0.65);

  /* Spacing scale (4px base) */
  --sp-1: 4px;
  --sp-2: 8px;
  --sp-3: 12px;
  --sp-4: 16px;
  --sp-5: 20px;
  --sp-6: 24px;
  --sp-8: 32px;
  --sp-10: 40px;

  /* Radii */
  --r-sm: 8px;
  --r-md: 14px;
  --r-lg: 20px;
  --r-xl: 28px;
  --r-full: 9999px;

  /* Transitions */
  --ease: cubic-bezier(0.4, 0, 0.2, 1);
  --spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --t-fast: 0.15s;
  --t-base: 0.25s;
  --t-slow: 0.4s;

  /* Typography */
  --font-display: 'Orbitron', 'Segoe UI', sans-serif;
  --font-body: 'Inter', system-ui, -apple-system, sans-serif;

  /* Shadows */
  --shadow-glow: 0 0 30px rgba(var(--accent-rgb), 0.08);
  --shadow-glow-m: 0 0 50px rgba(var(--accent-rgb), 0.12);
  --shadow-card: 0 4px 24px rgba(0, 0, 0, 0.3), 0 0 1px rgba(255, 255, 255, 0.06);
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

button,
select {
  font: inherit;
}

ul {
  list-style: none;
}

/* ─────────────────── Body & Canvas ─────────────────── */
body {
  font-family: var(--font-body);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  overflow-x: hidden;
  transition: background var(--t-base) var(--ease), color var(--t-base) var(--ease);
  -webkit-font-smoothing: antialiased;
}

/* Animated gradient underlay */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  z-index: 0;
  background:
    radial-gradient(ellipse 80% 60% at 50% 0%, rgba(var(--accent-rgb), 0.06) 0%, transparent 70%),
    radial-gradient(ellipse 60% 50% at 80% 100%, rgba(var(--accent-sec-rgb), 0.04) 0%, transparent 70%),
    radial-gradient(ellipse 50% 40% at 10% 60%, rgba(168, 85, 247, 0.03) 0%, transparent 70%);
  pointer-events: none;
  animation: ambientShift 12s ease-in-out infinite alternate;
}

@keyframes ambientShift {
  0% {
    opacity: 0.8;
    filter: hue-rotate(0deg);
  }

  100% {
    opacity: 1;
    filter: hue-rotate(15deg);
  }
}

#bgCanvas {
  position: fixed;
  inset: 0;
  width: 100vw;
  height: 100vh;
  z-index: 0;
  pointer-events: none;
}

/* Main content wrapper */
.app-wrapper {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 800px;
  min-height: 100dvh;
  padding: var(--sp-4) var(--sp-4) 0;
}

/* ═══════════════════ HEADER ═══════════════════ */
.app-header {
  width: 100%;
  text-align: center;
  padding: var(--sp-6) 0 var(--sp-3);
}

.app-header h1 {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 5.5vw, 2.8rem);
  font-weight: 700;
  letter-spacing: 6px;
  color: var(--accent);
  text-shadow:
    0 0 10px rgba(var(--accent-rgb), 0.6),
    0 0 40px rgba(var(--accent-rgb), 0.3),
    0 0 80px rgba(var(--accent-rgb), 0.15);
  animation: titleGlow 3s ease-in-out infinite alternate;
}

@keyframes titleGlow {
  from {
    text-shadow: 0 0 10px rgba(var(--accent-rgb), 0.6), 0 0 40px rgba(var(--accent-rgb), 0.3);
  }

  to {
    text-shadow: 0 0 16px rgba(var(--accent-rgb), 0.8), 0 0 60px rgba(var(--accent-rgb), 0.4), 0 0 100px rgba(var(--accent-rgb), 0.15);
  }
}


/* ═══════════════════ CONTROLS BAR ═══════════════════ */
.controls {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: var(--sp-2);
  margin: var(--sp-3) 0;
  width: 100%;
}

.ctrl-btn,
.controls select {
  font-family: var(--font-body);
  font-size: 0.82rem;
  font-weight: 600;
  padding: var(--sp-2) var(--sp-4);
  border-radius: var(--r-sm);
  border: 1px solid var(--border-glow);
  background: var(--bg-card);
  color: var(--text-primary);
  cursor: pointer;
  transition: all var(--t-base) var(--ease);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  white-space: nowrap;
  outline: none;
}

.ctrl-btn:hover,
.controls select:hover {
  background: rgba(var(--accent-rgb), 0.1);
  border-color: rgba(var(--accent-rgb), 0.5);
  box-shadow: 0 0 18px rgba(var(--accent-rgb), 0.12);
  color: var(--accent);
}

.ctrl-btn:active {
  transform: scale(0.94);
  transition-duration: 0.08s;
}

/* Focus-visible for keyboard users */
.ctrl-btn:focus-visible,
.controls select:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(var(--accent-rgb), 0.15);
}

/* Sound toggle active state */
#soundToggle.muted {
  color: var(--text-muted);
  border-color: rgba(255, 255, 255, 0.06);
}

/* ═══════════════════ SCOREBOARD CARDS ═══════════════════ */
.scoreboard {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--sp-3);
  width: 100%;
  margin: var(--sp-2) 0 var(--sp-3);
  align-items: stretch;
}

.score-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: var(--sp-3) var(--sp-4);
  background: var(--bg-card);
  border-radius: var(--r-md);
  border: 1px solid var(--border-glow);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  box-shadow: var(--shadow-card);
  transition: all var(--t-base) var(--ease);
}

.score-card:hover {
  border-color: rgba(var(--accent-rgb), 0.4);
  box-shadow: var(--shadow-card), var(--shadow-glow);
  transform: translateY(-2px);
}

.score-card .label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: var(--sp-1);
}

.score-card .score-value {
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 4vw, 2rem);
  font-weight: 700;
  line-height: 1;
}

.score-card.player .score-value {
  color: var(--accent);
  text-shadow: 0 0 14px rgba(var(--accent-rgb), 0.5);
}

.score-card.opponent .score-value {
  color: var(--accent-secondary);
  text-shadow: 0 0 14px rgba(var(--accent-sec-rgb), 0.5);
}

/* VS divider */
.vs-divider {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
}

.vs-badge {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 2px;
  color: var(--text-muted);
  padding: var(--sp-1) var(--sp-3);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: var(--r-full);
  background: var(--bg-card);
}

/* ═══════════════════ STATS ROW ═══════════════════ */
.stats-bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--sp-4);
  width: 100%;
  padding: var(--sp-3) var(--sp-5);
  background: var(--bg-card);
  border-radius: var(--r-md);
  border: 1px solid rgba(255, 255, 255, 0.04);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  margin-bottom: var(--sp-2);
}

.stat-item {
  font-size: 0.82rem;
  color: var(--text-secondary);
  display: flex;
  align-items: center;
  gap: var(--sp-1);
}

.stat-item .value {
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

#levelDisplay {
  font-family: var(--font-display);
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--accent-secondary);
  text-shadow: 0 0 10px rgba(var(--accent-sec-rgb), 0.4);
  letter-spacing: 1px;
}

/* ═══════════════════ TURN INDICATOR ═══════════════════ */
#turnIndicator {
  font-family: var(--font-display);
  font-size: clamp(0.85rem, 2.5vw, 1.05rem);
  text-align: center;
  min-height: 1.6em;
  margin: var(--sp-2) 0 var(--sp-3);
  padding: var(--sp-2) var(--sp-5);
  color: var(--accent);
  letter-spacing: 1px;
  text-shadow: 0 0 12px rgba(var(--accent-rgb), 0.4);
  border-radius: var(--r-full);
  background: rgba(var(--accent-rgb), 0.04);
  border: 1px solid rgba(var(--accent-rgb), 0.1);
  transition: all var(--t-base) var(--ease);
}

#turnIndicator:empty {
  opacity: 0;
  padding: 0;
  margin: 0;
  min-height: 0;
  border: none;
}

/* ═══════════════════ GAME AREA ═══════════════════ */
.game-area {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  gap: var(--sp-5);
  width: 100%;
}

/* ═══════════════════ BOARD ═══════════════════ */
#board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 6px;
  width: clamp(260px, 52vw, 360px);
  aspect-ratio: 1;
  padding: 10px;
  background: var(--bg-card);
  border-radius: var(--r-lg);
  border: 1px solid var(--border-glow);
  box-shadow:
    var(--shadow-card),
    0 0 60px rgba(var(--accent-rgb), 0.06),
    inset 0 0 40px rgba(var(--accent-rgb), 0.02);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  transition: box-shadow var(--t-slow) var(--ease);
}

#board:hover {
  box-shadow:
    var(--shadow-card),
    0 0 80px rgba(var(--accent-rgb), 0.1),
    inset 0 0 50px rgba(var(--accent-rgb), 0.03);
}

/* ─── Cells ─── */
.cell {
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  background: var(--cell-bg);
  border-radius: var(--r-sm);
  border: 1px solid rgba(255, 255, 255, 0.04);
  cursor: pointer;
  transition: all var(--t-base) var(--ease);
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
}

/* Subtle inner glow on hover */
.cell::before {
  content: '';
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: radial-gradient(circle at center, rgba(var(--accent-rgb), 0.08) 0%, transparent 70%);
  opacity: 0;
  transition: opacity var(--t-base) var(--ease);
  pointer-events: none;
}

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

.cell:hover {
  background: var(--cell-hover);
  border-color: rgba(var(--accent-rgb), 0.35);
  box-shadow: 0 0 20px rgba(var(--accent-rgb), 0.1), inset 0 0 12px rgba(var(--accent-rgb), 0.03);
}

.cell:active {
  transform: scale(0.92);
  transition-duration: 0.08s;
}

.cell:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: -2px;
}

/* ─── Marks ─── */
.mark {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3.2rem);
  font-weight: 700;
  pointer-events: none;
  opacity: 0;
  transform: scale(0.2) rotate(-25deg);
  transition: all 0.4s var(--spring);
  line-height: 1;
}

.mark.appear {
  opacity: 1;
  transform: scale(1) rotate(0deg);
}

.mark-x {
  color: var(--accent);
  text-shadow:
    0 0 8px rgba(var(--accent-rgb), 0.7),
    0 0 20px rgba(var(--accent-rgb), 0.4),
    0 0 40px rgba(var(--accent-rgb), 0.15);
  filter: drop-shadow(0 0 6px rgba(var(--accent-rgb), 0.4));
}

.mark-o {
  color: var(--accent-secondary);
  text-shadow:
    0 0 8px rgba(var(--accent-sec-rgb), 0.7),
    0 0 20px rgba(var(--accent-sec-rgb), 0.4),
    0 0 40px rgba(var(--accent-sec-rgb), 0.15);
  filter: drop-shadow(0 0 6px rgba(var(--accent-sec-rgb), 0.4));
}

/* ─── Winning Cells ─── */
.win-cell {
  animation: winPulse 0.7s ease-in-out infinite alternate;
  border-color: rgba(var(--gold-rgb), 0.6) !important;
}

.win-cell::after {
  content: '';
  position: absolute;
  inset: -2px;
  border-radius: inherit;
  background: radial-gradient(circle, rgba(var(--gold-rgb), 0.12) 0%, transparent 75%);
  animation: winGlowExpand 1.4s ease-in-out infinite alternate;
  pointer-events: none;
}

@keyframes winPulse {
  from {
    box-shadow: 0 0 12px rgba(var(--gold-rgb), 0.3), inset 0 0 8px rgba(var(--gold-rgb), 0.08);
  }

  to {
    box-shadow: 0 0 28px rgba(var(--gold-rgb), 0.6), inset 0 0 18px rgba(var(--gold-rgb), 0.15);
    transform: scale(1.03);
  }
}

@keyframes winGlowExpand {
  from {
    opacity: 0.4;
  }

  to {
    opacity: 1;
  }
}

/* ═══════════════════ BOARD ANIMATIONS ═══════════════════ */

/* 3D flip when a mark is placed */
.cell-flip {
  animation: cellFlip 0.4s ease;
}

@keyframes cellFlip {
  0% {
    transform: rotateY(90deg) scale(0.8);
    opacity: 0.3;
  }

  60% {
    transform: rotateY(-10deg) scale(1.05);
    opacity: 1;
  }

  100% {
    transform: rotateY(0deg) scale(1);
    opacity: 1;
  }
}

/* Board shake on AI win */
.board-shake {
  animation: boardShake 0.5s ease;
}

@keyframes boardShake {

  0%,
  100% {
    transform: translateX(0);
  }

  10% {
    transform: translateX(-8px) rotate(-1deg);
  }

  20% {
    transform: translateX(8px) rotate(1deg);
  }

  30% {
    transform: translateX(-6px) rotate(-0.5deg);
  }

  40% {
    transform: translateX(6px) rotate(0.5deg);
  }

  50% {
    transform: translateX(-4px);
  }

  60% {
    transform: translateX(4px);
  }

  70% {
    transform: translateX(-2px);
  }

  80% {
    transform: translateX(2px);
  }
}

/* Hint glow pulse on suggested cell */
.hint-glow {
  animation: hintPulse 0.6s ease-in-out 3;
  border-color: rgba(var(--gold-rgb), 0.8) !important;
}

@keyframes hintPulse {

  0%,
  100% {
    box-shadow: 0 0 8px rgba(var(--gold-rgb), 0.2), inset 0 0 6px rgba(var(--gold-rgb), 0.05);
  }

  50% {
    box-shadow: 0 0 24px rgba(var(--gold-rgb), 0.6), inset 0 0 16px rgba(var(--gold-rgb), 0.12);
    border-color: rgba(var(--gold-rgb), 1) !important;
  }
}


/* ═══════════════════ LOBBY POPUP ═══════════════════ */


.lobby-card {
  max-width: 480px;
}

.lobby-subtitle {
  color: var(--text-secondary);
  font-size: 0.88rem;
  margin-bottom: var(--sp-6);
}

.lobby-sections {
  display: flex;
  flex-direction: column;
  gap: var(--sp-5);
  margin-bottom: var(--sp-6);
}

.lobby-section {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-3);
}

/* Divider */
.lobby-divider {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 2px;
}

.lobby-divider::before,
.lobby-divider::after {
  content: '';
  flex: 1;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.08), transparent);
}

/* Room code display */
.room-code-display {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 5vw, 2.6rem);
  font-weight: 700;
  letter-spacing: 8px;
  color: var(--accent);
  text-shadow:
    0 0 12px rgba(var(--accent-rgb), 0.6),
    0 0 40px rgba(var(--accent-rgb), 0.3);
  padding: var(--sp-4) var(--sp-6);
  background: rgba(var(--accent-rgb), 0.05);
  border: 1px solid rgba(var(--accent-rgb), 0.2);
  border-radius: var(--r-md);
  user-select: all;
  cursor: copy;
  animation: codeAppear 0.4s var(--spring);
}

@keyframes codeAppear {
  from {
    opacity: 0;
    transform: scale(0.8);
  }

  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* Join input group */
.join-input-group {
  display: flex;
  gap: var(--sp-2);
  width: 100%;
  max-width: 320px;
}

.lobby-input {
  flex: 1;
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 4px;
  text-align: center;
  text-transform: uppercase;
  padding: var(--sp-3) var(--sp-4);
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-glow);
  border-radius: var(--r-sm);
  color: var(--text-primary);
  outline: none;
  transition: all var(--t-base) var(--ease);
}

.lobby-input::placeholder {
  font-family: var(--font-body);
  font-size: 0.82rem;
  font-weight: 400;
  letter-spacing: 0.5px;
  text-transform: none;
  color: var(--text-muted);
}

.lobby-input:focus {
  border-color: rgba(var(--accent-rgb), 0.5);
  box-shadow: 0 0 16px rgba(var(--accent-rgb), 0.12);
  background: rgba(var(--accent-rgb), 0.04);
}

/* Status bar */
.lobby-status-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  padding: var(--sp-3) var(--sp-4);
  margin-bottom: var(--sp-5);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--r-sm);
  border: 1px solid rgba(255, 255, 255, 0.03);
}

.lobby-status-text {
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.room-details {
  display: flex;
  justify-content: space-around;
  margin-bottom: var(--sp-5);
  padding: var(--sp-3);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--r-sm);
  border: 1px solid rgba(255, 255, 255, 0.03);
}

.room-stat {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.room-stat-label {
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
}

.room-stat-value {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--accent);
}

.room-actions-bar {
  display: flex;
  gap: var(--sp-3);
  margin-bottom: var(--sp-5);
  justify-content: center;
}

.status-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--text-muted);
  flex-shrink: 0;
  transition: background var(--t-base) var(--ease);
}

.status-dot.green {
  background: #22c55e;
  box-shadow: 0 0 8px rgba(34, 197, 94, 0.5);
}

.status-dot.yellow {
  background: #eab308;
  box-shadow: 0 0 8px rgba(234, 179, 8, 0.4);
  animation: dotPulse 1.2s ease-in-out infinite;
}

.status-dot.red {
  background: #ef4444;
  box-shadow: 0 0 8px rgba(239, 68, 68, 0.4);
}

@keyframes dotPulse {

  0%,
  100% {
    opacity: 1;
  }

  50% {
    opacity: 0.3;
  }
}

/* Room action buttons */
.room-actions {
  display: flex;
  gap: var(--sp-2);
  justify-content: center;
  flex-wrap: wrap;
}

.btn-icon {
  font-size: 0.78rem;
  font-weight: 600;
  padding: var(--sp-2) var(--sp-3);
  border-radius: var(--r-sm);
  border: 1px solid var(--border-glow);
  background: var(--bg-card);
  color: var(--text-secondary);
  cursor: pointer;
  transition: all var(--t-base) var(--ease);
  outline: none;
  white-space: nowrap;
}

.btn-icon:hover {
  background: rgba(var(--accent-rgb), 0.1);
  border-color: rgba(var(--accent-rgb), 0.4);
  color: var(--accent);
}

.btn-icon:active {
  transform: scale(0.95);
  transition-duration: 0.08s;
}

/* Button variants */
.btn-create {
  width: 100%;
  max-width: 260px;
  background: rgba(var(--accent-rgb), 0.12) !important;
}

.btn-join {
  padding: var(--sp-3) var(--sp-5) !important;
  flex-shrink: 0;
}

.btn-leave {
  border-color: var(--text-muted) !important;
  color: var(--text-muted) !important;
  background: transparent !important;
  font-size: 0.78rem !important;
  padding: var(--sp-2) var(--sp-5) !important;
}

.btn-leave:hover {
  border-color: var(--text-secondary) !important;
  color: var(--text-secondary) !important;
  background: rgba(255, 255, 255, 0.03) !important;
  box-shadow: none !important;
  transform: none !important;
}


/* ═══════════════════ FOOTER SETTINGS ═══════════════════ */
.app-footer {
  width: 100%;
  margin-top: auto;
  padding: var(--sp-5) 0 var(--sp-4);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-3);
}

.footer-settings {
  display: flex;
  align-items: center;
  gap: var(--sp-4);
}

.footer-settings .settings-label {
  font-size: 0.7rem;
  font-weight: 600;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  color: var(--text-muted);
}

/* Theme switcher */
.theme-switcher {
  display: flex;
  gap: var(--sp-2);
  padding: var(--sp-1);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--r-full);
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.theme-btn {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 2px solid transparent;
  cursor: pointer;
  transition: all var(--t-base) var(--ease);
  position: relative;
  outline: none;
}

.theme-btn::after {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: 50%;
  border: 2px solid transparent;
  transition: border-color var(--t-base) var(--ease);
}

.theme-btn:hover {
  transform: scale(1.15);
}

.theme-btn:focus-visible::after {
  border-color: var(--accent);
}

.theme-btn.active {
  border-color: var(--accent);
  box-shadow: 0 0 12px rgba(var(--accent-rgb), 0.35);
}

.theme-btn[data-theme="dark"] {
  background: #0a0a1a;
}

.theme-btn[data-theme="light"] {
  background: linear-gradient(135deg, #e2e8f0, #f8fafc);
}

.theme-btn[data-theme="neon"] {
  background: linear-gradient(135deg, #ff006e, #a855f7, #00e5ff);
}

.theme-btn[data-theme="woodBoard"] {
  background: linear-gradient(135deg, #8c6239, #3e2a1e);
}

.theme-btn[data-theme="spaceTheme"] {
  background: radial-gradient(circle at center, #64ffda 10%, #0a192f 80%);
}

.footer-copyright {
  font-size: 0.7rem;
  color: var(--text-muted);
  letter-spacing: 0.5px;
}

/* ═══════════════════ POPUPS / MODALS ═══════════════════ */
.popup {
  position: fixed;
  inset: 0;
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 10000;
  padding: var(--sp-4);
}

.popup.active {
  display: flex;
}

/* Overlay */
.popup::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--overlay);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  animation: overlayFadeIn var(--t-base) var(--ease);
}

@keyframes overlayFadeIn {
  from {
    opacity: 0;
  }

  to {
    opacity: 1;
  }
}

/* Card */
.popup-card {
  position: relative;
  background: var(--popup-bg);
  border: 1px solid var(--border-glow);
  border-radius: var(--r-lg);
  padding: var(--sp-10) var(--sp-8);
  max-width: 440px;
  width: 100%;
  text-align: center;
  animation: cardEnter 0.45s var(--spring);
  box-shadow:
    0 8px 40px rgba(0, 0, 0, 0.4),
    0 0 60px rgba(var(--accent-rgb), 0.08),
    inset 0 1px 0 rgba(255, 255, 255, 0.04);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

@keyframes cardEnter {
  from {
    transform: scale(0.6) translateY(30px);
    opacity: 0;
  }

  to {
    transform: scale(1) translateY(0);
    opacity: 1;
  }
}

/* Decorative top bar */
.popup-card::before {
  content: '';
  position: absolute;
  top: 0;
  left: 20%;
  right: 20%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent), transparent);
  border-radius: 0 0 var(--r-sm) var(--r-sm);
}

.popup-card h2 {
  font-family: var(--font-display);
  font-size: clamp(1.3rem, 4vw, 1.7rem);
  font-weight: 700;
  color: var(--accent);
  text-shadow: 0 0 20px rgba(var(--accent-rgb), 0.4);
  margin-bottom: var(--sp-4);
  letter-spacing: 1px;
}

.popup-card p {
  color: var(--text-secondary);
  font-size: 0.92rem;
  line-height: 1.7;
  margin-bottom: var(--sp-6);
}

/* Popup CTA buttons */
.popup-card .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--sp-2);
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  padding: var(--sp-3) var(--sp-8);
  border-radius: var(--r-sm);
  border: 1px solid var(--accent);
  background: rgba(var(--accent-rgb), 0.08);
  color: var(--accent);
  cursor: pointer;
  transition: all var(--t-base) var(--ease);
  outline: none;
}

.popup-card .btn:hover {
  background: var(--accent);
  color: var(--bg-primary);
  box-shadow: 0 0 30px rgba(var(--accent-rgb), 0.35);
  transform: translateY(-1px);
}

.popup-card .btn:active {
  transform: scale(0.96) translateY(0);
  transition-duration: 0.08s;
}

.popup-card .btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

/* ─── Champion popup special styling ─── */
#championPopup .popup-card {
  border-color: rgba(var(--gold-rgb), 0.4);
  box-shadow:
    0 8px 40px rgba(0, 0, 0, 0.4),
    0 0 80px rgba(var(--gold-rgb), 0.12);
}

#championPopup .popup-card::before {
  background: linear-gradient(90deg, transparent, var(--gold), transparent);
}

#championPopup .popup-card h2 {
  color: var(--gold);
  text-shadow: 0 0 20px rgba(var(--gold-rgb), 0.5);
  font-size: clamp(1.5rem, 5vw, 2rem);
}

#championPopup .popup-card .btn {
  border-color: var(--gold);
  color: var(--gold);
  background: rgba(var(--gold-rgb), 0.08);
}

#championPopup .popup-card .btn:hover {
  background: var(--gold);
  color: #000;
  box-shadow: 0 0 30px rgba(var(--gold-rgb), 0.4);
}

/* ─── AI Win special ─── */
#aiWinPopup .popup-card h2 {
  color: var(--accent-secondary);
  text-shadow: 0 0 20px rgba(var(--accent-sec-rgb), 0.4);
}

/* ─── Level Up special ─── */
#levelUpPopup .popup-card::before {
  background: linear-gradient(90deg, transparent, var(--accent-tertiary), transparent);
}

#levelUpPopup .popup-card h2 {
  color: var(--accent-tertiary);
  text-shadow: 0 0 20px rgba(168, 85, 247, 0.4);
}

/* ─── Instructions wider ─── */
#instructionsPopup .popup-card {
  max-width: 520px;
  padding: var(--sp-8) var(--sp-8);
}

#instructionsPopup .popup-card p {
  text-align: left;
  font-size: 0.86rem;
}

#instructionsPopup .rules-list {
  text-align: left;
  margin-bottom: var(--sp-5);
}

#instructionsPopup .rules-list li {
  color: var(--text-secondary);
  font-size: 0.86rem;
  line-height: 1.7;
  padding: var(--sp-2) 0;
  padding-left: var(--sp-5);
  position: relative;
}

#instructionsPopup .rules-list li::before {
  content: '›';
  position: absolute;
  left: var(--sp-1);
  color: var(--accent);
  font-weight: 700;
}

#instructionsPopup .rules-list li+li {
  border-top: 1px solid rgba(255, 255, 255, 0.03);
}

/* ═══════════════════ SCORE BUMP ANIMATION ═══════════════════ */
@keyframes scoreBump {
  0% {
    transform: scale(1);
  }

  40% {
    transform: scale(1.3);
  }

  70% {
    transform: scale(0.95);
  }

  100% {
    transform: scale(1);
  }
}

.score-bump {
  animation: scoreBump 0.4s var(--spring);
}

/* ═══════════════════ ACCESSIBILITY ═══════════════════ */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Reduced motion preference */
@media (prefers-reduced-motion: reduce) {

  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* ═══════════════════ SKIP LINK ═══════════════════ */

.skip-link {
  position: absolute;
  top: -100px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent);
  color: var(--bg-body);
  padding: var(--sp-2) var(--sp-4);
  border-radius: var(--r-sm);
  font-weight: 700;
  font-size: 0.85rem;
  z-index: 9999;
  transition: top var(--t-base) var(--ease);
}

.skip-link:focus {
  top: var(--sp-3);
}

/* ═══════════════════ STATS SIDEBAR ═══════════════════ */

.stats-sidebar {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 280px;
  max-width: 90vw;
  background: var(--bg-card);
  border-left: 1px solid var(--border-glow);
  backdrop-filter: blur(24px);
  -webkit-backdrop-filter: blur(24px);
  box-shadow: -8px 0 32px rgba(0, 0, 0, 0.3);
  z-index: 800;
  transform: translateX(100%);
  transition: transform var(--t-base) var(--spring);
  overflow-y: auto;
  padding: var(--sp-5);
  display: flex;
  flex-direction: column;
  gap: var(--sp-5);
}

.stats-sidebar.open {
  transform: translateX(0);
}

.stats-sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.stats-sidebar-header h2 {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 1px;
  color: var(--text-primary);
}

.stats-close {
  background: none;
  border: none;
  color: var(--text-muted);
  font-size: 1.5rem;
  cursor: pointer;
  line-height: 1;
  padding: var(--sp-1);
  border-radius: var(--r-sm);
  transition: color var(--t-fast), background var(--t-fast);
}

.stats-close:hover {
  color: var(--text-primary);
  background: rgba(255, 255, 255, 0.06);
}

/* Win-rate ring */
.stats-ring-wrap {
  position: relative;
  width: 120px;
  height: 120px;
  margin: 0 auto;
}

.stats-ring-svg {
  width: 100%;
  height: 100%;
}

.stats-ring-label {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}

.stats-ring-value {
  font-family: var(--font-display);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--accent);
}

.stats-ring-text {
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--text-muted);
}

/* Stats grid */
.stats-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--sp-2);
}

.stats-cell {
  text-align: center;
  padding: var(--sp-3);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--r-sm);
  border: 1px solid rgba(255, 255, 255, 0.04);
}

.stats-cell.wins .stats-cell-value {
  color: #22c55e;
}

.stats-cell.losses .stats-cell-value {
  color: #ef4444;
}

.stats-cell-value {
  display: block;
  font-family: var(--font-display);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text-primary);
}

.stats-cell-label {
  display: block;
  font-size: 0.65rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 1px;
  color: var(--text-muted);
  margin-top: 2px;
}

/* Extras */
.stats-extras {
  display: flex;
  flex-direction: column;
  gap: var(--sp-2);
}

.stats-extra-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--sp-2) var(--sp-3);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--r-sm);
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.stats-extra-value {
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--accent);
}

/* ═══════════════════ RESPONSIVE ═══════════════════ */

/* Tablet & small desktop */
@media (max-width: 700px) {
  .game-area {
    flex-direction: column;
    align-items: center;
    gap: var(--sp-3);
  }

  .scoreboard {
    gap: var(--sp-2);
  }

  .controls {
    flex-wrap: wrap;
    justify-content: center;
  }
}

/* Phone */
@media (max-width: 500px) {
  .app-wrapper {
    padding: var(--sp-3);
  }

  .app-header h1 {
    font-size: clamp(1.2rem, 6vw, 1.8rem);
  }

  .subtitle {
    font-size: clamp(0.5rem, 2.5vw, 0.7rem);
  }

  .controls {
    gap: var(--sp-1);
  }

  .ctrl-btn {
    font-size: 0.7rem;
    padding: var(--sp-2) var(--sp-2);
  }

  #board {
    width: 280px;
  }

  .popup-card {
    padding: var(--sp-6) var(--sp-5);
  }
}

/* Very small */
@media (max-width: 360px) {
  #board {
    width: 260px;
  }

  .mark {
    font-size: 1.8rem;
  }

  .scoreboard {
    grid-template-columns: 1fr 1fr;
  }

  .vs-divider {
    display: none;
  }

  .popup-card {
    padding: var(--sp-5) var(--sp-4);
  }
}

/* ═══════════════════ REPLAY SYSTEM ═══════════════════ */
.replay-bar {
  position: absolute;
  bottom: var(--sp-4);
  left: 50%;
  transform: translateX(-50%) translateY(20px);
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--border-glow);
  border-radius: var(--r-full);
  padding: var(--sp-3) var(--sp-5);
  display: flex;
  gap: var(--sp-3);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  z-index: 500;
  opacity: 0;
  pointer-events: none;
  transition: all var(--t-base) var(--spring);
}

.replay-bar.active {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
  pointer-events: auto;
}

.history-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--sp-3);
  background: rgba(255, 255, 255, 0.02);
  border-radius: var(--r-sm);
  margin-bottom: var(--sp-2);
  transition: background var(--t-fast) var(--ease);
}

.history-item:hover {
  background: rgba(255, 255, 255, 0.05);
}

.hi-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.hi-info strong {
  font-family: var(--font-display);
  font-size: 0.95rem;
}

.history-item.win strong {
  color: #22c55e;
}

.history-item.loss strong {
  color: #ef4444;
}

.history-item.draw strong {
  color: #facc15;
}

.hi-info span {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.hi-info .hi-date {
  font-size: 0.65rem;
  color: var(--text-muted);
  opacity: 0.8;
}