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

:root {
  --bg-deep: #0a0e1a;
  --bg-card: rgba(18, 24, 42, 0.75);
  --border: rgba(255, 255, 255, 0.08);
  --text: #e8ecf4;
  --text-muted: #8892a8;
  --x-color: #ff6b6b;
  --x-glow: rgba(255, 107, 107, 0.45);
  --o-color: #4ecdc4;
  --o-glow: rgba(78, 205, 196, 0.45);
  --accent: #a78bfa;
  --accent-glow: rgba(167, 139, 250, 0.35);
  --cell-bg: rgba(255, 255, 255, 0.04);
  --cell-hover: rgba(255, 255, 255, 0.08);
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
  font-size: 16px;
}

body {
  font-family: 'Outfit', system-ui, sans-serif;
  background: var(--bg-deep);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow-x: hidden;
  padding: 1.5rem;
}

/* Animated background */
.background {
  position: fixed;
  inset: 0;
  z-index: 0;
  overflow: hidden;
  background: linear-gradient(135deg, #0a0e1a 0%, #12182e 40%, #0f1525 100%);
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
  opacity: 0.5;
  animation: float 12s ease-in-out infinite;
}

.orb-1 {
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, var(--x-glow), transparent 70%);
  top: -10%;
  left: -5%;
}

.orb-2 {
  width: 350px;
  height: 350px;
  background: radial-gradient(circle, var(--o-glow), transparent 70%);
  bottom: -10%;
  right: -5%;
  animation-delay: -4s;
}

.orb-3 {
  width: 300px;
  height: 300px;
  background: radial-gradient(circle, var(--accent-glow), transparent 70%);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation-delay: -8s;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  33% { transform: translate(30px, -20px) scale(1.05); }
  66% { transform: translate(-20px, 15px) scale(0.95); }
}

/* Layout */
.app {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 480px;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.header {
  text-align: center;
}

.title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.title-x {
  color: var(--x-color);
  text-shadow: 0 0 20px var(--x-glow);
}

.title-o {
  color: var(--o-color);
  text-shadow: 0 0 20px var(--o-glow);
}

.subtitle {
  margin-top: 0.35rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 400;
}

/* Scoreboard */
.scoreboard {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
}

.score-card {
  background: var(--bg-card);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 0.85rem 0.5rem;
  text-align: center;
  transition: var(--transition);
}

.score-card:hover {
  border-color: rgba(255, 255, 255, 0.15);
}

.score-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.score-x .score-label { color: var(--x-color); }
.score-o .score-label { color: var(--o-color); }

.score-value {
  font-size: 1.75rem;
  font-weight: 800;
  line-height: 1;
}

/* Game panel */
.game-panel {
  background: var(--bg-card);
  backdrop-filter: blur(16px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 1.5rem;
  box-shadow: var(--shadow);
}

.status-bar {
  display: flex;
  justify-content: center;
  margin-bottom: 1.25rem;
}

.turn-indicator {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.5rem 1.25rem;
  transition: var(--transition);
}

.turn-piece {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 28px;
  height: 28px;
  border-radius: 8px;
  font-weight: 800;
  font-size: 1rem;
  animation: pulse-turn 2s ease-in-out infinite;
}

.turn-piece.turn-x {
  background: rgba(255, 107, 107, 0.15);
  color: var(--x-color);
  box-shadow: 0 0 12px var(--x-glow);
}

.turn-piece.turn-o {
  background: rgba(78, 205, 196, 0.15);
  color: var(--o-color);
  box-shadow: 0 0 12px var(--o-glow);
}

@keyframes pulse-turn {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.08); }
}

.turn-text {
  font-weight: 600;
  font-size: 0.95rem;
}

/* Board */
.board {
  position: relative;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  aspect-ratio: 1;
  margin-bottom: 1.25rem;
}

.cell {
  position: relative;
  background: var(--cell-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-family: inherit;
  font-size: 2.75rem;
  font-weight: 800;
  color: transparent;
  transition: background var(--transition), border-color var(--transition), transform 0.15s ease;
  overflow: hidden;
}

.cell:not(:disabled):hover {
  background: var(--cell-hover);
  border-color: rgba(255, 255, 255, 0.18);
  transform: scale(1.03);
}

.cell:not(:disabled):active {
  transform: scale(0.97);
}

.cell:disabled {
  cursor: default;
}

.cell.x {
  color: var(--x-color);
  text-shadow: 0 0 24px var(--x-glow);
  animation: pop-in 0.35s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

.cell.o {
  color: var(--o-color);
  text-shadow: 0 0 24px var(--o-glow);
  animation: pop-in 0.35s cubic-bezier(0.34, 1.56, 0.64, 1) forwards;
}

.cell.win {
  background: rgba(167, 139, 250, 0.12);
  border-color: var(--accent);
  animation: win-glow 1s ease-in-out infinite alternate;
}

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

@keyframes win-glow {
  0% { box-shadow: 0 0 8px var(--accent-glow); }
  100% { box-shadow: 0 0 24px var(--accent-glow), inset 0 0 12px rgba(167, 139, 250, 0.1); }
}

/* Win line SVG overlay */
.win-line {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.3s ease;
  z-index: 2;
}

.win-line.visible {
  opacity: 1;
}

.win-line line {
  stroke: var(--accent);
  stroke-width: 3;
  stroke-linecap: round;
  filter: drop-shadow(0 0 6px var(--accent));
  stroke-dasharray: 200;
  stroke-dashoffset: 200;
  animation: draw-line 0.5s ease forwards;
}

@keyframes draw-line {
  to { stroke-dashoffset: 0; }
}

/* Controls */
.controls {
  display: flex;
  gap: 0.75rem;
}

.btn {
  flex: 1;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1rem;
  border: none;
  border-radius: var(--radius-sm);
  font-family: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent), #7c3aed);
  color: white;
  box-shadow: 0 4px 16px var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 24px var(--accent-glow);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-secondary {
  background: rgba(255, 255, 255, 0.06);
  color: var(--text-muted);
  border: 1px solid var(--border);
}

.btn-secondary:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--text);
}

.btn-large {
  padding: 0.9rem 2rem;
  font-size: 1rem;
}

/* Modal */
.modal-overlay {
  position: fixed;
  inset: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.6);
  backdrop-filter: blur(6px);
  padding: 1.5rem;
  animation: fade-in 0.3s ease;
}

.modal-overlay[hidden] {
  display: none;
}

@keyframes fade-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

.modal {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 2rem;
  text-align: center;
  max-width: 340px;
  width: 100%;
  box-shadow: var(--shadow);
  animation: slide-up 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

@keyframes slide-up {
  from { transform: translateY(30px) scale(0.95); opacity: 0; }
  to { transform: translateY(0) scale(1); opacity: 1; }
}

.modal-icon {
  font-size: 3.5rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  line-height: 1;
}

.modal-icon.icon-x {
  color: var(--x-color);
  text-shadow: 0 0 30px var(--x-glow);
}

.modal-icon.icon-o {
  color: var(--o-color);
  text-shadow: 0 0 30px var(--o-glow);
}

.modal-icon.icon-draw {
  color: var(--text-muted);
}

.modal-title {
  font-size: 1.5rem;
  font-weight: 800;
  margin-bottom: 0.35rem;
}

.modal-message {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  font-size: 0.95rem;
}

/* Responsive */
@media (max-width: 400px) {
  .title { font-size: 1.6rem; }
  .cell { font-size: 2.25rem; }
  .controls { flex-direction: column; }
  .score-value { font-size: 1.5rem; }
}