/**
 * Tic-Tac-Toe - Kreuzbau Theme
 */

:root {
  /* Kreuzbau Design System */
  --kb-primary: #3B82F6;
  --kb-primary-hover: #2563EB;
  --kb-accent: #06B6D4;
  --kb-success: #22C55E;
  --kb-error: #EF4444;

  --kb-dark-bg: #0F172A;
  --kb-dark-surface: #1E293B;
  --kb-dark-raised: #334155;
  --kb-dark-border: #475569;
  --kb-dark-text: #F8FAFC;
  --kb-dark-text-secondary: #94A3B8;
  --kb-dark-text-muted: #64748B;

  --kb-bg: var(--kb-dark-bg);
  --kb-surface: var(--kb-dark-surface);
  --kb-raised: var(--kb-dark-raised);
  --kb-border: var(--kb-dark-border);
  --kb-text: var(--kb-dark-text);
  --kb-text-secondary: var(--kb-dark-text-secondary);
  --kb-text-muted: var(--kb-dark-text-muted);

  --kb-font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --kb-radius-md: 0.5rem;
  --kb-radius-lg: 0.75rem;
  --kb-transition-base: 0.15s ease;
  --kb-shadow-glow-primary: 0 0 20px rgba(59, 130, 246, 0.3);
}

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

body.kb-base {
  font-family: var(--kb-font-sans);
  background: var(--kb-bg);
  color: var(--kb-text);
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  -webkit-font-smoothing: antialiased;
}

.container {
  text-align: center;
  padding: 2rem;
  max-width: 100%;
}

header h1 {
  font-size: 2.5rem;
  font-weight: 700;
  color: var(--kb-primary);
  margin-bottom: 0.5rem;
}

.subtitle {
  color: var(--kb-text-secondary);
  font-size: 1rem;
  margin-bottom: 2rem;
}

.status {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--kb-text);
  margin-bottom: 1.5rem;
  min-height: 2rem;
}

.status.win {
  color: var(--kb-success);
}

.status.lose {
  color: var(--kb-error);
}

.status.draw {
  color: var(--kb-accent);
}

/* Game Board */
.board {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.75rem;
  max-width: 320px;
  margin: 0 auto 2rem;
}

.cell {
  aspect-ratio: 1;
  background: var(--kb-surface);
  border: 2px solid var(--kb-border);
  border-radius: var(--kb-radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--kb-transition-base);
  user-select: none;
}

.cell:hover:not(.taken) {
  background: var(--kb-raised);
  border-color: var(--kb-primary);
  box-shadow: var(--kb-shadow-glow-primary);
}

.cell.taken {
  cursor: not-allowed;
}

.cell.x {
  color: var(--kb-primary);
}

.cell.o {
  color: var(--kb-accent);
}

.cell.winner {
  background: var(--kb-raised);
  animation: pulse 0.6s ease-in-out infinite alternate;
}

@keyframes pulse {
  from { transform: scale(1); }
  to { transform: scale(1.05); }
}

/* Reset Button */
.reset-btn {
  background: var(--kb-primary);
  color: white;
  border: none;
  padding: 0.875rem 2rem;
  font-size: 1rem;
  font-weight: 600;
  border-radius: var(--kb-radius-lg);
  cursor: pointer;
  transition: all var(--kb-transition-base);
}

.reset-btn:hover {
  background: var(--kb-primary-hover);
  transform: translateY(-2px);
}

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

/* Footer */
footer {
  margin-top: 3rem;
  color: var(--kb-text-muted);
  font-size: 0.875rem;
}

footer a {
  color: var(--kb-accent);
  text-decoration: none;
}

footer a:hover {
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 480px) {
  .container {
    padding: 1rem;
  }

  header h1 {
    font-size: 2rem;
  }

  .board {
    max-width: 280px;
    gap: 0.5rem;
  }

  .cell {
    font-size: 2.5rem;
  }

  .reset-btn {
    width: 100%;
    padding: 1rem;
  }
}

@media (min-width: 768px) {
  .board {
    max-width: 360px;
  }

  .cell {
    font-size: 4rem;
  }
}