:root {
  --bg-start: #060512;
  --bg-mid: #12052f;
  --bg-end: #031a26;
  --panel: rgba(10, 14, 34, 0.78);
  --panel-border: rgba(97, 255, 234, 0.25);
  --text-main: #f7fbff;
  --text-soft: #9fb5d1;
  --cyan: #58f6ff;
  --pink: #ff4fd8;
  --lime: #b7ff65;
  --shadow-cyan: 0 0 22px rgba(88, 246, 255, 0.45);
  --shadow-pink: 0 0 28px rgba(255, 79, 216, 0.35);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Rajdhani", sans-serif;
  color: var(--text-main);
  background:
    radial-gradient(circle at top left, rgba(255, 79, 216, 0.2), transparent 30%),
    radial-gradient(circle at top right, rgba(88, 246, 255, 0.18), transparent 35%),
    linear-gradient(135deg, var(--bg-start), var(--bg-mid) 45%, var(--bg-end));
  overflow-x: hidden;
}

body::before,
body::after {
  content: "";
  position: fixed;
  inset: auto;
  width: 22rem;
  height: 22rem;
  border-radius: 50%;
  filter: blur(40px);
  opacity: 0.35;
  pointer-events: none;
}

body::before {
  top: -6rem;
  left: -4rem;
  background: rgba(255, 79, 216, 0.45);
}

body::after {
  right: -5rem;
  bottom: -5rem;
  background: rgba(88, 246, 255, 0.32);
}

.confetti-layer {
  position: fixed;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  z-index: 20;
}

.confetti-piece {
  position: absolute;
  width: 0.8rem;
  height: 1rem;
  border-radius: 0.2rem;
  opacity: 0.9;
  animation: confetti-fall linear forwards;
}

.app-shell {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 2rem 1rem;
}

.panel {
  width: min(100%, 54rem);
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 1.75rem;
  padding: 2rem;
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow-cyan), var(--shadow-pink);
  transition: transform 0.35s ease, opacity 0.35s ease;
}

.hero-panel,
.setup-block,
.status-card,
.score-pill {
  animation: fade-up 0.6s ease both;
}

.hidden {
  display: none;
}

.eyebrow {
  margin: 0 0 0.4rem;
  font-family: "Orbitron", sans-serif;
  font-size: 0.8rem;
  letter-spacing: 0.2rem;
  text-transform: uppercase;
  color: var(--cyan);
}

.brand-logo {
  display: block;
  width: min(100%, 24rem);
  margin: 0 auto 1rem;
  filter:
    drop-shadow(0 0 12px rgba(88, 246, 255, 0.65))
    drop-shadow(0 0 24px rgba(255, 79, 216, 0.35));
}

h1,
h2 {
  margin: 0;
  font-family: "Orbitron", sans-serif;
}

h1 {
  font-size: clamp(2.6rem, 8vw, 4.8rem);
  text-shadow: 0 0 22px rgba(88, 246, 255, 0.45);
}

h2 {
  font-size: clamp(1.3rem, 5vw, 2rem);
}

.lead {
  margin: 1rem 0 2rem;
  max-width: 32rem;
  font-size: 1.15rem;
  line-height: 1.5;
  color: var(--text-soft);
}

.credit {
  margin: -0.75rem 0 1.5rem;
  color: var(--text-soft);
  font-size: 1rem;
}

.credit-link {
  color: var(--cyan);
  text-decoration: none;
  text-shadow: 0 0 14px rgba(88, 246, 255, 0.45);
}

.credit-link:hover {
  color: var(--lime);
}

button {
  border: 0;
  cursor: pointer;
  font: inherit;
}

.primary-button,
.secondary-button,
.option-button {
  border-radius: 999px;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.primary-button {
  padding: 0.95rem 2.4rem;
  font-family: "Orbitron", sans-serif;
  font-size: 1rem;
  color: #041018;
  background: linear-gradient(135deg, var(--lime), var(--cyan));
  box-shadow: 0 0 30px rgba(183, 255, 101, 0.35);
}

.primary-button:hover,
.secondary-button:hover,
.option-button:hover,
.cell:hover:not(:disabled) {
  transform: translateY(-2px);
}

.secondary-button {
  padding: 0.8rem 1.2rem;
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.setup-block + .setup-block {
  margin-top: 2rem;
}

.setup-actions {
  display: flex;
  justify-content: flex-start;
  margin-bottom: 1rem;
}

.setup-block.disabled {
  opacity: 0.45;
  pointer-events: none;
}

.option-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(9rem, 1fr));
  gap: 1rem;
  margin-top: 1rem;
}

.option-button {
  padding: 1rem;
  background: rgba(8, 18, 38, 0.9);
  color: var(--text-main);
  border: 1px solid rgba(88, 246, 255, 0.18);
}

.option-button.selected {
  background: linear-gradient(135deg, rgba(255, 79, 216, 0.22), rgba(88, 246, 255, 0.24));
  box-shadow: 0 0 18px rgba(88, 246, 255, 0.22);
  border-color: rgba(183, 255, 101, 0.55);
}

.game-topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
}

.game-actions {
  display: flex;
  gap: 0.75rem;
}

.status-card {
  margin: 1.4rem 0;
  padding: 1rem 1.2rem;
  border-radius: 1rem;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.12);
}

.status-card p {
  margin: 0;
  font-size: 1.15rem;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.8rem;
}

.panel#game-screen.game-zoomed {
  transform: scale(0.5);
  transform-origin: center;
}

.board[data-size="4"] .cell {
  font-size: clamp(1.7rem, 7vw, 2.5rem);
}

.board[data-size="5"] .cell {
  font-size: clamp(1.3rem, 5vw, 2rem);
}

.cell {
  aspect-ratio: 1;
  border-radius: 1.2rem;
  background:
    linear-gradient(135deg, rgba(255, 255, 255, 0.08), rgba(255, 255, 255, 0.03)),
    rgba(4, 11, 27, 0.9);
  border: 1px solid rgba(88, 246, 255, 0.16);
  color: var(--text-main);
  font-family: "Orbitron", sans-serif;
  font-size: clamp(2rem, 10vw, 3.3rem);
  text-shadow: 0 0 18px rgba(255, 255, 255, 0.25);
}

.cell.x-mark {
  color: var(--cyan);
  text-shadow: 0 0 18px rgba(88, 246, 255, 0.7);
}

.cell.o-mark {
  color: var(--pink);
  text-shadow: 0 0 18px rgba(255, 79, 216, 0.7);
}

.cell.selected-piece {
  border-color: rgba(183, 255, 101, 0.9);
  box-shadow: 0 0 24px rgba(183, 255, 101, 0.4);
}

.cell:disabled {
  cursor: default;
}

.scoreboard {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1rem;
  margin-top: 1.5rem;
}

.score-pill {
  padding: 0.9rem 1rem;
  border-radius: 1rem;
  text-align: center;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid rgba(255, 255, 255, 0.1);
}

.score-pill span {
  display: block;
  color: var(--text-soft);
}

.score-pill strong {
  font-family: "Orbitron", sans-serif;
  font-size: 1.5rem;
}

.pulse {
  animation: pulse 1.8s infinite ease-in-out;
}

@keyframes pulse {
  0%, 100% {
    box-shadow: 0 0 20px rgba(183, 255, 101, 0.25);
  }
  50% {
    box-shadow: 0 0 34px rgba(88, 246, 255, 0.5);
  }
}

@keyframes fade-up {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes confetti-fall {
  0% {
    opacity: 0;
    transform: translateY(0) rotate(0deg);
  }
  10% {
    opacity: 1;
  }
  100% {
    opacity: 0;
    transform: translateY(115vh) rotate(680deg);
  }
}

@media (max-width: 640px) {
  .panel {
    padding: 1.4rem;
  }

  .game-topbar {
    flex-direction: column;
    align-items: flex-start;
  }

  .game-actions {
    width: 100%;
  }

  .game-actions .secondary-button {
    flex: 1;
  }

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