/* ===== UTTK Premium UI V5.0 - Automotive Grade ===== */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800;900&family=Space+Grotesk:wght@400;500;600;700&display=swap');

:root {
  /* Color System - Deep Navy + Warm Orange (Automotive Classic) */
  --navy-900: #0a0f1e;
  --navy-800: #0f1629;
  --navy-700: #162038;
  --navy-600: #1e2d4d;
  --navy-500: #2a3d63;
  --orange-500: #f97316;
  --orange-400: #fb923c;
  --orange-300: #fdba74;
  --amber-400: #fbbf24;
  --cyan-400: #22d3ee;
  --green-400: #34d399;
  --white: #ffffff;
  --gray-100: #f1f5f9;
  --gray-300: #cbd5e1;
  --gray-400: #94a3b8;
  --gray-500: #64748b;
  --gray-600: #475569;

  /* Semantic */
  --bg: var(--navy-900);
  --bg-elevated: var(--navy-800);
  --bg-card: rgba(22, 32, 56, 0.6);
  --bg-card-hover: rgba(30, 45, 77, 0.8);
  --primary: var(--orange-500);
  --primary-light: var(--orange-400);
  --accent: var(--cyan-400);
  --text: var(--gray-100);
  --text-secondary: var(--gray-400);
  --text-muted: var(--gray-500);
  --border: rgba(148, 163, 184, 0.1);
  --border-light: rgba(148, 163, 184, 0.18);
  --border-primary: rgba(249, 115, 22, 0.3);

  /* Gradients */
  --gradient-primary: linear-gradient(135deg, #f97316 0%, #fb923c 100%);
  --gradient-hero: linear-gradient(180deg, rgba(249, 115, 22, 0.06) 0%, transparent 100%);
  --gradient-card: linear-gradient(135deg, rgba(22, 32, 56, 0.8) 0%, rgba(15, 22, 41, 0.9) 100%);
  --gradient-text: linear-gradient(135deg, #ffffff 0%, #94a3b8 100%);
  --gradient-orange-text: linear-gradient(135deg, #fb923c 0%, #fbbf24 100%);

  /* Shadows */
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.4);
  --shadow-lg: 0 16px 48px rgba(0,0,0,0.5);
  --shadow-orange: 0 8px 32px rgba(249, 115, 22, 0.25);
  --shadow-card: 0 4px 24px rgba(0,0,0,0.3);

  /* Radius */
  --r-sm: 8px;
  --r-md: 14px;
  --r-lg: 20px;
  --r-xl: 28px;

  /* Spacing (8px system) */
  --sp-1: 4px; --sp-2: 8px; --sp-3: 12px; --sp-4: 16px;
  --sp-5: 20px; --sp-6: 24px; --sp-8: 32px; --sp-10: 40px;
  --sp-12: 48px; --sp-16: 64px; --sp-20: 80px;
}

* { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Ambient Background */
body::before {
  content: '';
  position: fixed; inset: 0;
  background:
    radial-gradient(ellipse 800px 600px at 20% -10%, rgba(249, 115, 22, 0.05), transparent),
    radial-gradient(ellipse 600px 500px at 80% 20%, rgba(34, 211, 238, 0.04), transparent);
  pointer-events: none; z-index: 0;
}

.container { max-width: 1160px; margin: 0 auto; padding: 0 var(--sp-8); position: relative; z-index: 1; }

/* ===== Navbar ===== */
.navbar {
  position: sticky; top: 0; z-index: 1000;
  background: rgba(10, 15, 30, 0.85);
  backdrop-filter: blur(20px) saturate(160%);
  -webkit-backdrop-filter: blur(20px) saturate(160%);
  border-bottom: 1px solid var(--border);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; padding: var(--sp-4) 0; }
.logo { display: flex; align-items: center; gap: var(--sp-3); text-decoration: none; }
.logo-icon {
  width: 40px; height: 40px; border-radius: var(--r-sm);
  background: var(--gradient-primary);
  display: flex; align-items: center; justify-content: center;
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 700; font-size: 16px; color: white;
  box-shadow: var(--shadow-orange);
}
.logo-text { display: flex; flex-direction: column; }
.logo-title { font-family: 'Space Grotesk', sans-serif; font-size: 17px; font-weight: 700; color: var(--text); letter-spacing: -0.3px; }
.logo-sub { font-size: 10px; color: var(--text-muted); letter-spacing: 1px; text-transform: uppercase; }
.nav-links { display: flex; list-style: none; gap: 2px; align-items: center; }
.nav-links a {
  color: var(--text-secondary); text-decoration: none; font-size: 13.5px; font-weight: 500;
  padding: var(--sp-2) var(--sp-3); border-radius: var(--r-sm); transition: all 0.2s;
}
.nav-links a:hover { color: var(--text); background: rgba(148, 163, 184, 0.06); }
.nav-links a.active { color: var(--orange-400); background: rgba(249, 115, 22, 0.08); }
.nav-cta {
  background: var(--gradient-primary) !important; color: white !important;
  font-weight: 600 !important; padding: var(--sp-2) var(--sp-5) !important;
  border-radius: var(--r-sm) !important; margin-left: var(--sp-2);
  box-shadow: 0 2px 10px rgba(249, 115, 22, 0.3);
}
.nav-cta:hover { box-shadow: 0 4px 20px rgba(249, 115, 22, 0.45) !important; transform: translateY(-1px); }
.mobile-toggle { display: none; background: none; border: none; color: var(--text); font-size: 20px; cursor: pointer; }

/* ===== Hero ===== */
.hero { position: relative; padding: var(--sp-20) 0 var(--sp-16); background: var(--gradient-hero); overflow: hidden; }
.hero-badge {
  display: inline-flex; align-items: center; gap: var(--sp-2);
  padding: 6px 14px; background: rgba(249, 115, 22, 0.08);
  border: 1px solid var(--border-primary); border-radius: 100px;
  font-size: 12px; font-weight: 600; color: var(--orange-400); margin-bottom: var(--sp-6);
}
.hero-badge::before { content: ''; width: 6px; height: 6px; background: var(--green-400); border-radius: 50%; box-shadow: 0 0 8px var(--green-400); }
.hero h1 {
  font-family: 'Space Grotesk', sans-serif;
  font-size: 46px; font-weight: 700; line-height: 1.12; letter-spacing: -1.2px;
  margin-bottom: var(--sp-5); max-width: 700px;
}
.hero h1 .highlight { background: var(--gradient-orange-text); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.hero-desc { font-size: 16px; color: var(--text-secondary); max-width: 600px; margin-bottom: var(--sp-8); line-height: 1.85; }
.hero-desc strong { color: var(--text); font-weight: 600; }
.hero-buttons { display: flex; gap: var(--sp-3); margin-bottom: var(--sp-12); flex-wrap: wrap; }

.btn {
  display: inline-flex; align-items: center; gap: var(--sp-2);
  padding: 13px 26px; border-radius: var(--r-md); font-size: 14.5px; font-weight: 600;
  text-decoration: none; transition: all 0.2s; cursor: pointer; border: none; letter-spacing: -0.2px;
}
.btn-primary { background: var(--gradient-primary); color: white; box-shadow: var(--shadow-orange); }
.btn-primary:hover { transform: translateY(-2px); box-shadow: 0 12px 36px rgba(249, 115, 22, 0.4); }
.btn-secondary { background: rgba(148, 163, 184, 0.06); color: var(--text); border: 1px solid var(--border-light); }
.btn-secondary:hover { background: rgba(148, 163, 184, 0.12); border-color: var(--gray-500); }
.btn-accent { background: rgba(34, 211, 238, 0.08); color: var(--cyan-400); border: 1px solid rgba(34, 211, 238, 0.2); }
.btn-accent:hover { background: rgba(34, 211, 238, 0.14); }

.hero-stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--sp-4); max-width: 660px; }
.stat-item {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--r-md);
  padding: var(--sp-5) var(--sp-4); backdrop-filter: blur(8px); transition: all 0.25s;
}
.stat-item:hover { border-color: var(--border-primary); transform: translateY(-2px); }
.stat-item h3 { font-family: 'Space Grotesk', sans-serif; font-size: 28px; font-weight: 700; color: var(--text); letter-spacing: -0.8px; margin-bottom: 2px; }
.stat-item p { font-size: 11.5px; color: var(--text-muted); margin: 0; letter-spacing: 0.3px; }

/* ===== Section ===== */
.section { padding: var(--sp-16) 0; position: relative; z-index: 1; }
.section-title { text-align: center; margin-bottom: var(--sp-12); }
.section-title h2 { font-family: 'Space Grotesk', sans-serif; font-size: 32px; font-weight: 700; letter-spacing: -0.8px; color: var(--text); margin-bottom: var(--sp-3); }
.section-title h2 span { background: var(--gradient-orange-text); -webkit-background-clip: text; -webkit-text-fill-color: transparent; background-clip: text; }
.section-title p { font-size: 15px; color: var(--text-secondary); max-width: 540px; margin: 0 auto; }

/* ===== Cards ===== */
.card-grid { display: grid; gap: var(--sp-5); }
.card-grid-2 { grid-template-columns: repeat(2, 1fr); }
.card-grid-3 { grid-template-columns: repeat(3, 1fr); }
.card-grid-4 { grid-template-columns: repeat(4, 1fr); }
.card {
  background: var(--gradient-card); border: 1px solid var(--border); border-radius: var(--r-lg);
  padding: var(--sp-7); backdrop-filter: blur(8px); transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.card:hover { border-color: var(--border-primary); transform: translateY(-4px); box-shadow: var(--shadow-lg); }
.card-icon {
  width: 44px; height: 44px; border-radius: var(--r-md);
  background: rgba(249, 115, 22, 0.1); display: flex; align-items: center; justify-content: center;
  font-size: 22px; margin-bottom: var(--sp-4);
}
.card h3 { font-size: 16px; font-weight: 700; color: var(--text); margin-bottom: var(--sp-2); letter-spacing: -0.2px; }
.card p { font-size: 13.5px; color: var(--text-secondary); line-height: 1.75; }
.team-card { text-align: center; }
.team-avatar {
  width: 52px; height: 52px; border-radius: 50%; margin: 0 auto var(--sp-3);
  background: var(--gradient-primary); display: flex; align-items: center; justify-content: center;
  font-size: 20px; font-weight: 700; color: white;
}
.role { font-size: 11px; color: var(--orange-400); font-weight: 600; margin-bottom: 4px; letter-spacing: 0.5px; text-transform: uppercase; }

/* ===== Highlight Box ===== */
.highlight-box {
  background: linear-gradient(135deg, rgba(249, 115, 22, 0.05), rgba(34, 211, 238, 0.03));
  border: 1px solid var(--border-primary); border-radius: var(--r-lg);
  padding: var(--sp-6) var(--sp-7); margin-bottom: var(--sp-5);
}
.highlight-box p { font-size: 14.5px; line-height: 2; color: var(--text-secondary); }
.highlight-box strong { color: var(--text); font-weight: 700; }

/* ===== CTA ===== */
.cta-section {
  background: linear-gradient(135deg, rgba(249, 115, 22, 0.06), rgba(34, 211, 238, 0.03));
  border-top: 1px solid var(--border); border-bottom: 1px solid var(--border);
  padding: var(--sp-16) 0; text-align: center; position: relative; z-index: 1;
}
.cta-section h2 { font-family: 'Space Grotesk', sans-serif; font-size: 28px; font-weight: 700; letter-spacing: -0.6px; margin-bottom: var(--sp-3); }
.cta-section p { color: var(--text-secondary); font-size: 15px; margin-bottom: var(--sp-6); }

/* ===== FAQ ===== */
.faq-list { max-width: 820px; margin: 0 auto; }
.faq-item {
  background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--r-md);
  margin-bottom: 10px; overflow: hidden; transition: all 0.2s;
}
.faq-item:hover { border-color: rgba(249, 115, 22, 0.2); }
.faq-question {
  padding: var(--sp-4) var(--sp-6); font-size: 14.5px; font-weight: 600; color: var(--text);
  cursor: pointer; display: flex; justify-content: space-between; align-items: center; gap: var(--sp-4);
}
.faq-question::after { content: '+'; font-size: 18px; font-weight: 300; color: var(--gray-500); flex-shrink: 0; transition: transform 0.2s; }
.faq-item.open .faq-question::after { transform: rotate(45deg); }
.faq-answer { padding: 0 var(--sp-6) var(--sp-5); font-size: 13.5px; line-height: 1.85; color: var(--text-secondary); }

/* ===== TL;DR ===== */
.tldr-box {
  background: linear-gradient(135deg, rgba(249, 115, 22, 0.05), rgba(34, 211, 238, 0.03));
  border-left: 3px solid var(--orange-500); padding: var(--sp-4) var(--sp-6);
  width: calc(100% - 2 * var(--sp-8)); max-width: 1096px;
  margin: var(--sp-6) auto; border-radius: 0 var(--r-md) var(--r-md) 0;
}
.tldr-box strong { color: var(--orange-400); font-size: 15px; font-weight: 700; letter-spacing: 0.2px; }
.tldr-box p { font-size: 14px; line-height: 1.8; color: var(--text-secondary); margin: 8px 0 0 0; }

/* ===== Gallery ===== */
.gallery-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--sp-4); margin: var(--sp-8) 0; }
.gallery-item {
  border-radius: var(--r-lg); overflow: hidden; border: 1px solid var(--border);
  aspect-ratio: 4/3; position: relative; background: var(--navy-800);
}
.gallery-item img { width: 100%; height: 100%; object-fit: cover; transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1); }
.gallery-item:hover img { transform: scale(1.08); }
.gallery-item::after {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(180deg, transparent 40%, rgba(0,0,0,0.4) 100%);
  opacity: 0; transition: opacity 0.3s;
}
.gallery-item:hover::after { opacity: 1; }
.hero-image { width: 100%; max-height: 400px; object-fit: cover; border-radius: var(--r-xl); border: 1px solid var(--border); box-shadow: var(--shadow-lg); }

/* ===== Table ===== */
.table-wrap { overflow-x: auto; border-radius: var(--r-md); border: 1px solid var(--border); }
table { width: 100%; border-collapse: collapse; font-size: 13.5px; }
thead tr { background: rgba(249, 115, 22, 0.08); }
th { padding: 12px 16px; text-align: left; font-weight: 700; color: var(--orange-300); font-size: 12px; letter-spacing: 0.5px; text-transform: uppercase; }
td { padding: 11px 16px; border-bottom: 1px solid var(--border); color: var(--text-secondary); }
tbody tr:last-child td { border-bottom: none; }
tbody tr:hover { background: rgba(148, 163, 184, 0.03); }

/* ===== Footer ===== */
.footer { background: rgba(6, 9, 18, 0.95); border-top: 1px solid var(--border); padding: var(--sp-14) 0 var(--sp-6); position: relative; z-index: 1; }
.footer-grid { display: grid; grid-template-columns: 1.5fr 1fr 1fr 1fr; gap: var(--sp-10); margin-bottom: var(--sp-10); }
.footer-brand p { font-size: 12.5px; color: var(--text-muted); line-height: 1.8; margin-top: var(--sp-3); }
.footer h4 { color: var(--text); font-size: 13px; font-weight: 700; margin-bottom: var(--sp-4); letter-spacing: -0.2px; }
.footer ul { list-style: none; }
.footer li { font-size: 12.5px; color: var(--text-muted); margin-bottom: 8px; line-height: 1.7; }
.footer a { color: var(--text-muted); text-decoration: none; transition: color 0.2s; }
.footer a:hover { color: var(--orange-400); }
.footer-bottom { text-align: center; padding-top: var(--sp-6); border-top: 1px solid var(--border); font-size: 11.5px; color: var(--text-muted); letter-spacing: 0.3px; }

/* ===== Responsive ===== */
@media (max-width: 960px) {
  .container { padding: 0 var(--sp-5); }
  .tldr-box { width: calc(100% - 2 * var(--sp-5)); }
  .card-grid-3, .card-grid-4 { grid-template-columns: repeat(2, 1fr); }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: repeat(2, 1fr); }
  .gallery-grid { grid-template-columns: repeat(2, 1fr); }
  .nav-links { display: none; }
  .nav-links.open {
    display: flex; position: absolute; top: 100%; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 4px;
    max-height: calc(100dvh - 64px); overflow-y: auto;
    padding: 12px 20px 20px; background: #0a0f1e;
    border: 1px solid var(--border); border-radius: 0 0 14px 14px;
    box-shadow: 0 14px 30px rgba(0,0,0,.35);
  }
  .nav-links.open li { width: 100%; }
  .nav-links.open a { display: block; padding: 12px 14px; font-size: 15px; }
  .nav-links.open .nav-cta { margin: 8px 0 0; text-align: center; }
  .mobile-toggle { display: block; }
  .hero h1 { font-size: 32px; }
  .section-title h2 { font-size: 24px; }
}
@media (max-width: 600px) {
  .card-grid-2, .card-grid-3, .card-grid-4 { grid-template-columns: 1fr; }
  .hero-stats { grid-template-columns: repeat(2, 1fr); }
  .footer-grid { grid-template-columns: 1fr; }
  .gallery-grid { grid-template-columns: 1fr; }
  .hero h1 { font-size: 23px; letter-spacing: -0.6px; }
  .hero { padding: var(--sp-14) 0 var(--sp-10); }
  .section { padding: var(--sp-12) 0; }
}

/* Native disclosure remains operable when JavaScript is unavailable. */
.faq-question { list-style: none; }
.faq-question::-webkit-details-marker { display: none; }