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

html {
  scroll-behavior: smooth;
  scroll-padding-top: 70px;
}

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

nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: rgba(10, 10, 26, 0.85);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  padding: 0 24px;
  height: 64px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  transition: background var(--transition);
}

[data-theme="light"] nav {
  background: rgba(240, 240, 248, 0.85);
}

.nav-links {
  display: flex;
  gap: 8px;
  list-style: none;
  flex-wrap: wrap;
}

.nav-links a {
  color: var(--text2);
  text-decoration: none;
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 0.9rem;
  transition: all var(--transition);
}

.nav-links a:hover,
.nav-links a:focus-visible {
  color: var(--accent2);
  background: rgba(108, 92, 231, 0.1);
}

.nav-links a.active {
  color: var(--accent2);
  background: rgba(108, 92, 231, 0.15);
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
}

.lang-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all var(--transition);
}

.lang-btn:hover,
.lang-btn:focus-visible {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.lang-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.toggle-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--text);
  padding: 6px 12px;
  border-radius: 6px;
  cursor: pointer;
  font-size: 0.85rem;
  transition: all var(--transition);
  white-space: nowrap;
}

.toggle-btn:hover,
.toggle-btn:focus-visible {
  border-color: var(--accent);
  color: var(--accent);
}

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

.section {
  min-height: 100vh;
  padding: 80px 24px 40px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  position: relative;
}

.section-content {
  max-width: 1100px;
  width: 100%;
}

.section-title {
  font-size: 2.2rem;
  font-weight: 700;
  margin-bottom: 12px;
  background: linear-gradient(135deg, var(--accent2), var(--accent3));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-desc {
  color: var(--text2);
  font-size: 1.05rem;
  margin-bottom: 32px;
  max-width: 600px;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  box-shadow: var(--shadow);
  transition: all var(--transition);
}

.card:hover {
  border-color: var(--accent);
  box-shadow: 0 8px 32px var(--glow);
}

.hero {
  text-align: center;
  padding-top: 100px;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 16px;
}

.hero p {
  font-size: 1.2rem;
  color: var(--text2);
  margin-bottom: 32px;
}

.canvas-container {
  width: 100%;
  height: 400px;
  border-radius: var(--radius);
  overflow: hidden;
  position: relative;
  background: var(--bg2);
}

.canvas-container canvas {
  width: 100%;
  height: 100%;
  display: block;
}

.game-container {
  display: flex;
  gap: 24px;
  flex-wrap: wrap;
  align-items: flex-start;
}

#gameCanvas {
  border: 2px solid var(--border);
  border-radius: 8px;
  background: #000;
}

.game-sidebar {
  display: flex;
  flex-direction: column;
  gap: 12px;
  min-width: 150px;
}

.chart-wrapper {
  height: 350px;
  position: relative;
}

.audio-controls {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: 20px;
}

.primary-btn {
  background: var(--accent);
  color: #fff;
  border: none;
  padding: 12px 28px;
  border-radius: 8px;
  font-size: 1rem;
  cursor: pointer;
  transition: all var(--transition);
}

.primary-btn:hover,
.primary-btn:focus-visible {
  background: var(--accent2);
  transform: translateY(-2px);
  box-shadow: 0 4px 20px var(--glow);
}

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

.secondary-btn {
  background: var(--surface2);
  color: var(--text);
  border: 1px solid var(--border);
  padding: 10px 24px;
  border-radius: 8px;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all var(--transition);
}

.secondary-btn:hover,
.secondary-btn:focus-visible {
  border-color: var(--accent);
  color: var(--accent);
}

#waveform {
  width: 100%;
  height: 120px;
  border-radius: 8px;
  background: var(--bg2);
}

.about-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin-top: 24px;
}

.feature-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  text-align: center;
  transition: all var(--transition);
}

.feature-card:hover {
  border-color: var(--accent);
  transform: translateY(-4px);
  box-shadow: 0 8px 32px var(--glow);
}

.feature-icon {
  font-size: 2.5rem;
  margin-bottom: 12px;
}

.feature-card h3 {
  margin-bottom: 8px;
  font-size: 1.1rem;
}

.feature-card p {
  color: var(--text2);
  font-size: 0.9rem;
}

footer {
  text-align: center;
  padding: 24px;
  border-top: 1px solid var(--border);
  color: var(--text2);
  font-size: 0.85rem;
}

.low-spec-indicator {
  display: none;
  background: rgba(253, 121, 168, 0.15);
  border: 1px solid var(--accent3);
  color: var(--accent3);
  padding: 10px 20px;
  border-radius: 8px;
  margin-bottom: 16px;
  text-align: center;
  font-size: 0.9rem;
}

.low-spec-indicator.visible {
  display: block;
}

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

@media (max-width: 768px) {
  nav {
    padding: 0 12px;
    height: auto;
    min-height: 56px;
    flex-wrap: wrap;
    gap: 8px;
  }

  .nav-links {
    gap: 4px;
  }

  .nav-links a {
    padding: 6px 10px;
    font-size: 0.8rem;
  }

  .nav-controls {
    gap: 6px;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .section-title {
    font-size: 1.6rem;
  }

  .game-container {
    flex-direction: column;
    align-items: center;
  }

  .canvas-container {
    height: 280px;
  }

  .chart-wrapper {
    height: 250px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}