:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-tertiary: #1a1a25;
  --text-primary: #ffffff;
  --text-secondary: #a0a0b0;
  --accent-primary: #6366f1;
  --accent-secondary: #8b5cf6;
  --accent-glow: #a855f7;
  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
  --border-color: rgba(255, 255, 255, 0.1);
  --glass-bg: rgba(255, 255, 255, 0.05);
  --shadow: 0 4px 30px rgba(0, 0, 0, 0.5);
}

[data-theme="light"] {
  --bg-primary: #f8fafc;
  --bg-secondary: #ffffff;
  --bg-tertiary: #f1f5f9;
  --text-primary: #0f172a;
  --text-secondary: #64748b;
  --accent-primary: #4f46e5;
  --accent-secondary: #7c3aed;
  --accent-glow: #a855f7;
  --border-color: rgba(0, 0, 0, 0.1);
  --glass-bg: rgba(255, 255, 255, 0.8);
  --shadow: 0 4px 30px rgba(0, 0, 0, 0.1);
}

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

html {
  scroll-behavior: smooth;
  scrollbar-width: thin;
  scrollbar-color: var(--accent-primary) var(--bg-secondary);
}

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}

::-webkit-scrollbar-track {
  background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
  background: var(--accent-primary);
  border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--accent-secondary);
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  overflow-x: hidden;
}

a {
  color: var(--accent-primary);
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover {
  color: var(--accent-secondary);
}

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

.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;
}

.container {
  width: 100%;
  max-width: 1400px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--glass-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  padding: 0.75rem 0;
}

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

.nav-brand {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  gap: 0.5rem;
  list-style: none;
}

.nav-links a {
  display: block;
  padding: 0.5rem 1rem;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 500;
  border-radius: 8px;
  transition: all 0.3s ease;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text-primary);
  background: var(--glass-bg);
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.lang-switcher {
  display: flex;
  gap: 0.25rem;
  background: var(--glass-bg);
  padding: 0.25rem;
  border-radius: 8px;
}

.lang-btn {
  padding: 0.375rem 0.75rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: transparent;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.lang-btn:hover {
  color: var(--text-primary);
}

.lang-btn.active {
  background: var(--accent-primary);
  color: white;
}

.toggle-btn {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.5rem 1rem;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
  background: var(--glass-bg);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.3s ease;
}

.toggle-btn:hover {
  color: var(--text-primary);
  border-color: var(--accent-primary);
}

.toggle-btn.active {
  background: var(--accent-primary);
  color: white;
  border-color: var(--accent-primary);
}

main {
  padding-top: 70px;
}

section {
  min-height: 100vh;
  padding: 4rem 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
}

.section-title {
  font-size: 2.5rem;
  font-weight: 800;
  margin-bottom: 0.5rem;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-glow));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  margin-bottom: 2rem;
}

canvas {
  display: block;
  border-radius: 16px;
  background: var(--bg-secondary);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  font-size: 0.875rem;
  font-weight: 600;
  color: white;
  background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: all 0.3s ease;
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
}

.btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px rgba(99, 102, 241, 0.5);
}

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

.btn-secondary {
  background: var(--glass-bg);
  color: var(--text-primary);
  border: 1px solid var(--border-color);
  box-shadow: none;
}

.btn-secondary:hover {
  border-color: var(--accent-primary);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.2);
}

.btn-group {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  justify-content: center;
}

.game-ui {
  position: absolute;
  top: 1rem;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  gap: 2rem;
  padding: 0.75rem 1.5rem;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border-radius: 12px;
  border: 1px solid var(--border-color);
}

.stat-label {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-primary);
}

.controls-hint {
  position: absolute;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%);
  padding: 0.75rem 1.5rem;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border-radius: 8px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.visualizer-container {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 2rem;
}

.algo-controls {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 1.5rem;
}

.range-control {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.range-control label {
  font-size: 0.875rem;
  color: var(--text-secondary);
  min-width: 80px;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  width: 120px;
  height: 6px;
  background: var(--bg-tertiary);
  border-radius: 3px;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 18px;
  height: 18px;
  background: var(--accent-primary);
  border-radius: 50%;
  cursor: pointer;
  transition: transform 0.2s ease;
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.2);
}

.about-content {
  max-width: 700px;
  text-align: center;
  padding: 2rem;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border-radius: 24px;
  border: 1px solid var(--border-color);
}

.about-content p {
  font-size: 1.125rem;
  color: var(--text-secondary);
  line-height: 1.8;
}

footer {
  padding: 2rem 0;
  text-align: center;
  border-top: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 0.875rem;
}

#threejs-container {
  width: 100%;
  max-width: 900px;
  height: 500px;
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
  }

  .section-title {
    font-size: 1.75rem;
  }

  .game-ui {
    gap: 1rem;
    padding: 0.5rem 1rem;
  }

  .stat-value {
    font-size: 1.25rem;
  }

  #threejs-container {
    height: 350px;
  }
}