/* ═══════════════════════════════════════════════════════════════
   OBDAssistant™ PREVIEW DESIGN SYSTEM — 2026 EDITION
   Premium Startup Aesthetic — Glassmorphism & High-Depth Dark Mode
   ═══════════════════════════════════════════════════════════════ */

:root {
  /* Core Palette */
  --c-bg:        #030306;
  --c-bg-sub:    #0a0a10;
  --c-surface:   rgba(18, 18, 26, 0.7);
  --c-surface-2: rgba(26, 26, 38, 0.8);
  --c-border:    rgba(255, 255, 255, 0.08);
  --c-border-h:  rgba(255, 255, 255, 0.15);
  
  /* Brand Accents */
  --c-accent:    #00e5ff; /* Hyper Cyan */
  --c-accent-rgb: 0, 229, 255;
  --c-purple:    #7c4dff; /* Deep Violet */
  --c-warm:      #ff6e40; /* Signal Orange */
  --c-success:   #00e676; /* Alert Green */
  
  /* Typography */
  --c-text:      #f0f0f5;
  --c-text-sub:  #94a3b8;
  --font-body:   'Inter', system-ui, -apple-system, sans-serif;
  --font-mono:   'JetBrains Mono', monospace;
  
  /* Effects */
  --glass:       blur(20px) saturate(1.8);
  --shadow-lg:   0 20px 50px -12px rgba(0, 0, 0, 0.5);
  --glow-accent: 0 0 30px rgba(0, 229, 255, 0.15);
  --radius-sm:   12px;
  --radius-md:   20px;
  --radius-lg:   32px;
}

/* ─── BASE RESET ─── */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }
html { scroll-behavior: smooth; font-size: 16px; }
body {
  font-family: var(--font-body);
  background: var(--c-bg);
  color: var(--c-text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

/* Subtle Animated Mesh Background */
body::before {
  content: '';
  position: fixed; inset: 0;
  background: 
    radial-gradient(circle at 15% 15%, rgba(0, 229, 255, 0.04) 0%, transparent 40%),
    radial-gradient(circle at 85% 85%, rgba(124, 77, 255, 0.04) 0%, transparent 40%);
  z-index: -1;
  pointer-events: none;
}

/* Film Grain */
.noise-overlay {
  position: fixed; inset: 0;
  background: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='4'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.02'/%3E%3C/svg%3E");
  pointer-events: none;
  z-index: 9999;
}

/* ─── LAYOUT ─── */
.container { max-width: 1200px; margin: 0 auto; padding: 0 24px; }
.wide-container { max-width: 1440px; margin: 0 auto; padding: 0 40px; }

/* ─── NAVIGATION ─── */
.nav {
  position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
  height: 72px;
  border-bottom: 1px solid var(--c-border);
  background: rgba(3, 3, 6, 0.6);
  backdrop-filter: var(--glass);
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}
.nav.scrolled { height: 60px; background: rgba(3, 3, 6, 0.8); }

.nav-inner {
  max-width: 1440px; margin: 0 auto; height: 100%;
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 40px;
}
.nav-brand {
  display: flex; align-items: center; gap: 12px;
  font-weight: 800; font-size: 1.25rem; color: #fff;
  text-decoration: none; letter-spacing: -0.03em;
}
.nav-brand .dot {
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--c-accent);
  box-shadow: 0 0 15px var(--c-accent);
}

.nav-links { display: flex; align-items: center; gap: 8px; }
.nav-links a:not(.nav-cta) {
  color: var(--c-text-sub); text-decoration: none;
  font-size: 0.9rem; font-weight: 500;
  padding: 8px 16px; border-radius: 8px;
  transition: all 0.2s;
}
.nav-links a:not(.nav-cta):hover { color: #fff; background: rgba(255, 255, 255, 0.05); }

.nav-cta {
  background: #fff; color: #000 !important;
  font-weight: 700; font-size: 0.9rem;
  padding: 10px 24px; border-radius: 12px;
  text-decoration: none; transition: all 0.3s;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.1);
}
.nav-cta:hover { transform: translateY(-2px); background: var(--c-accent); box-shadow: var(--glow-accent); }

/* ─── TYPOGRAPHY & TITLES ─── */
.gradient-text {
  background: linear-gradient(135deg, var(--c-accent), var(--c-purple));
  -webkit-background-clip: text; background-clip: text;
  -webkit-text-fill-color: transparent;
}
.section-label {
  display: inline-flex; align-items: center; gap: 10px;
  font-size: 0.75rem; font-weight: 700; color: var(--c-accent);
  text-transform: uppercase; letter-spacing: 0.15em;
  margin-bottom: 20px;
}
.section-label::before { content: ''; width: 30px; height: 1px; background: currentColor; opacity: 0.5; }

.section-title {
  font-size: clamp(2rem, 4vw, 3.2rem);
  font-weight: 800; letter-spacing: -0.04em;
  line-height: 1.1; color: #fff; margin-bottom: 24px;
}
.section-sub {
  font-size: 1.125rem; color: var(--c-text-sub);
  max-width: 600px; line-height: 1.7;
}

/* ─── BUTTONS ─── */
.btn {
  display: inline-flex; align-items: center; gap: 12px;
  padding: 16px 32px; border-radius: 14px;
  font-weight: 700; text-decoration: none;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  cursor: pointer; border: none;
}
.btn-primary { background: #fff; color: #000; }
.btn-primary:hover { background: var(--c-accent); transform: translateY(-3px); box-shadow: var(--glow-accent); }

.btn-secondary { background: rgba(255, 255, 255, 0.05); color: #fff; border: 1px solid var(--c-border); }
.btn-secondary:hover { background: rgba(255, 255, 255, 0.1); transform: translateY(-3px); border-color: var(--c-border-h); }

/* ─── CARDS ─── */
.card {
  background: var(--c-surface);
  border: 1px solid var(--c-border);
  border-radius: var(--radius-md);
  padding: 40px; transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}
.card:hover {
  background: var(--c-surface-2);
  border-color: var(--c-border-h);
  transform: translateY(-8px);
  box-shadow: var(--shadow-lg);
}

/* ─── FOOTER ─── */
.footer { padding: 100px 0 40px; border-top: 1px solid var(--c-border); background: var(--c-bg-sub); }
.footer-grid { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 60px; margin-bottom: 60px; }
.footer-brand p { color: var(--c-text-sub); margin-top: 20px; max-width: 320px; font-size: 0.95rem; }
.footer h4 { font-size: 0.8rem; font-weight: 700; color: #fff; text-transform: uppercase; letter-spacing: 0.1em; margin-bottom: 24px; }
.footer ul { list-style: none; display: flex; flex-direction: column; gap: 14px; }
.footer a { color: var(--c-text-sub); text-decoration: none; font-size: 0.9rem; transition: color 0.2s; }
.footer a:hover { color: var(--c-accent); }

.footer-bottom {
  padding-top: 40px; border-top: 1px solid var(--c-border);
  display: flex; justify-content: space-between; align-items: center;
  color: rgba(255, 255, 255, 0.3); font-size: 0.85rem;
}

/* ─── RESPONSIVE ─── */
@media (max-width: 1024px) {
  .footer-grid { grid-template-columns: 1fr 1fr; gap: 40px; }
  .nav-links { display: none; }
  .nav-inner { padding: 0 24px; }
}
@media (max-width: 640px) {
  .section-title { font-size: 2.4rem; }
  .footer-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; gap: 20px; text-align: center; }
}