/* ============================================
   Vehicle Physics - Base Styles
   ============================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --color-mechanics:    #e07030;
  --color-thermo:       #e04040;
  --color-vehicle:      #40a0e0;

  --bg-primary:    #0d0d1a;
  --bg-secondary:  #12122a;
  --bg-card:       #1a1a35;
  --bg-card-hover: #22224a;
  --border:        #2a2a50;

  --text-primary:   #e8e8f8;
  --text-secondary: #9090b8;
  --text-muted:     #5a5a88;

  --accent:      #40a0e0;
  --accent-glow: rgba(64, 160, 224, 0.3);

  --space-xs: 0.25rem; --space-sm: 0.5rem; --space-md: 1rem;
  --space-lg: 1.5rem; --space-xl: 2rem; --space-2xl: 3rem; --space-3xl: 4rem;

  --font-sans: 'Inter', 'Hiragino Sans', 'Yu Gothic', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;

  --radius-sm: 6px; --radius-md: 12px; --radius-lg: 20px;
  --shadow-sm: 0 2px 8px rgba(0,0,0,0.3);
  --shadow-md: 0 8px 24px rgba(0,0,0,0.4);
  --transition: 0.2s ease; --transition-slow: 0.4s ease;

  --domain: var(--accent);
}

html { scroll-behavior: smooth; }
body {
  font-family: var(--font-sans);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }

/* ---- Navigation ---- */
.site-nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  display: flex; align-items: center; justify-content: space-between;
  padding: var(--space-md) var(--space-xl);
  background: rgba(13, 13, 26, 0.85);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav-brand {
  display: flex; align-items: center; gap: var(--space-sm);
  font-weight: 700; font-size: 1.1rem;
}
.nav-brand .brand-icon { font-size: 1.5rem; }
.nav-links { display: flex; align-items: center; gap: var(--space-lg); list-style: none; }
.nav-links a { color: var(--text-secondary); font-size: 0.9rem; transition: color var(--transition); }
.nav-links a:hover { color: var(--text-primary); }
.nav-links a.active { color: var(--accent); }

/* ---- Layout ---- */
.page-wrapper { padding-top: 70px; min-height: 100vh; }
.container { max-width: 1100px; margin: 0 auto; padding: 0 var(--space-xl); }
.section { padding: var(--space-3xl) 0; }

/* ---- Hero ---- */
.hero {
  min-height: 90vh; display: flex; align-items: center; justify-content: center;
  text-align: center; position: relative; overflow: hidden;
  background: radial-gradient(ellipse at 50% 40%, #1a1040 0%, var(--bg-primary) 70%);
}
.hero-title {
  font-size: clamp(2.5rem, 6vw, 4.5rem);
  background: linear-gradient(135deg, #fff 0%, #40a0e0 50%, #e07030 100%);
  -webkit-background-clip: text; -webkit-text-fill-color: transparent;
  background-clip: text; margin-bottom: 1rem;
}
.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary); max-width: 600px; margin: 0 auto var(--space-xl);
}
.hero-bg-text {
  position: absolute; right: 5%; top: 50%; transform: translateY(-50%);
  font-size: 20vw; font-weight: 900;
  color: rgba(64, 160, 224, 0.04); font-family: serif;
  line-height: 1; pointer-events: none; user-select: none;
}

/* ---- Section Hero ---- */
.section-hero {
  min-height: 50vh; display: flex; align-items: center;
  background: radial-gradient(ellipse at 30% 50%, rgba(64,160,224,0.12) 0%, var(--bg-primary) 70%);
  background: radial-gradient(ellipse at 30% 50%, color-mix(in srgb, var(--domain) 15%, transparent) 0%, var(--bg-primary) 70%);
  padding: var(--space-3xl) 0; position: relative; overflow: hidden;
}
.breadcrumb { font-size: 0.85rem; color: var(--text-muted); margin-bottom: var(--space-md); }
.breadcrumb a { color: var(--text-secondary); }
.breadcrumb .sep { margin: 0 0.5rem; }
.domain-badge {
  display: inline-flex; padding: 4px 12px; border-radius: 20px;
  background: rgba(64,160,224,0.15);
  background: color-mix(in srgb, var(--domain) 15%, transparent);
  color: var(--domain); font-size: 0.75rem; font-weight: 700;
  text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: var(--space-md);
}

/* ---- Cards ---- */
.domain-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: var(--space-lg);
}
.domain-card {
  position: relative; background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-lg); padding: var(--space-xl); cursor: pointer;
  transition: transform var(--transition), border-color var(--transition), box-shadow var(--transition);
  overflow: hidden; display: block;
}
.domain-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, var(--card-color, var(--accent)) 0%, transparent 60%);
  opacity: 0; transition: opacity var(--transition-slow);
}
.domain-card:hover {
  transform: translateY(-4px);
  border-color: var(--card-color, var(--accent));
  box-shadow: 0 12px 40px rgba(0,0,0,0.4), 0 0 0 1px var(--card-color, var(--accent));
}
.domain-card:hover::before { opacity: 0.08; }
.domain-card .card-icon { font-size: 2.5rem; margin-bottom: var(--space-md); display: block; position: relative; z-index: 1; }
.domain-card .card-label {
  font-size: 0.75rem; font-weight: 600; text-transform: uppercase;
  letter-spacing: 0.1em; color: var(--card-color, var(--accent)); margin-bottom: var(--space-xs);
  position: relative; z-index: 1;
}
.domain-card h3 { font-size: 1.25rem; margin-bottom: var(--space-sm); position: relative; z-index: 1; }
.domain-card p { color: var(--text-secondary); font-size: 0.9rem; position: relative; z-index: 1; }

/* ---- Viz Card ---- */
.viz-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: var(--space-lg); margin-bottom: var(--space-xl);
}
.viz-card h3 { color: var(--text-primary); margin-bottom: var(--space-md); }
.viz-card p { color: var(--text-secondary); font-size: 0.9rem; margin-bottom: var(--space-md); }

/* ---- Controls ---- */
canvas.sim-canvas {
  width: 100%; height: 400px; background: #0a0a18;
  border-radius: var(--radius-md); border: 1px solid var(--border); display: block;
}
.controls {
  display: flex; flex-wrap: wrap; gap: var(--space-sm);
  align-items: center; margin-top: var(--space-md);
}
.controls label { color: var(--text-secondary); font-size: 0.85rem; }
.controls input[type="range"] { width: 140px; accent-color: var(--domain); }
.controls button {
  padding: 6px 16px; border: 1px solid var(--domain); background: transparent;
  color: var(--domain); border-radius: var(--radius-sm); cursor: pointer;
  font-size: 0.85rem; transition: all var(--transition);
}
.controls button:hover { background: var(--domain); color: #fff; }
.controls .val { color: var(--domain); font-family: var(--font-mono); font-size: 0.85rem; min-width: 50px; }
.controls select {
  background: var(--bg-card); color: var(--text-primary); border: 1px solid var(--border);
  padding: 4px 8px; border-radius: var(--radius-sm); font-size: 0.85rem;
}

.info-panel {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-md); padding: var(--space-lg);
  margin-top: var(--space-md); font-family: var(--font-mono); font-size: 0.85rem;
  color: var(--text-secondary); line-height: 1.8;
}
.info-panel .highlight { color: var(--domain); font-weight: 600; }

/* ---- Buttons ---- */
.btn {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 10px 24px; border-radius: var(--radius-sm);
  font-size: 0.9rem; font-weight: 600; transition: all var(--transition);
  cursor: pointer; border: none;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { filter: brightness(1.15); transform: translateY(-1px); }
.btn-outline { background: transparent; border: 1px solid var(--border); color: var(--text-secondary); }
.btn-outline:hover { border-color: var(--text-primary); color: var(--text-primary); }

/* ---- Responsive ---- */
@media (max-width: 768px) {
  .domain-grid { grid-template-columns: 1fr; }
  .site-nav {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--space-sm);
    padding: var(--space-sm) var(--space-md);
  }
  .nav-links {
    gap: var(--space-md);
    width: 100%;
    overflow-x: auto;
    padding-bottom: 4px;
    white-space: nowrap;
    scrollbar-width: none;
  }
  .nav-links::-webkit-scrollbar { display: none; }
  .nav-links li { flex: 0 0 auto; }
  .nav-links a { font-size: 0.8rem; }
  .container { padding: 0 var(--space-md); }
}