/* ============================================
   EduAR Design System — Premium Dark Theme
   ============================================ */
@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 {
  --bg-primary: #0a0e1a;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.7);
  --bg-glass: rgba(255,255,255,0.04);
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent-1: #6366f1;
  --accent-2: #8b5cf6;
  --accent-3: #a78bfa;
  --gradient-main: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a78bfa 100%);
  --gradient-warm: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);
  --gradient-cool: linear-gradient(135deg, #06b6d4 0%, #6366f1 100%);
  --gradient-bg: radial-gradient(ellipse at 20% 50%, rgba(99,102,241,0.15) 0%, transparent 50%),
                 radial-gradient(ellipse at 80% 20%, rgba(139,92,246,0.1) 0%, transparent 50%),
                 radial-gradient(ellipse at 50% 80%, rgba(6,182,212,0.08) 0%, transparent 50%);
  --border-subtle: rgba(255,255,255,0.06);
  --border-accent: rgba(99,102,241,0.3);
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.3);
  --shadow-md: 0 4px 20px rgba(0,0,0,0.4);
  --shadow-lg: 0 10px 40px rgba(0,0,0,0.5);
  --shadow-glow: 0 0 30px rgba(99,102,241,0.3);
  --radius-sm: 8px;
  --radius-md: 14px;
  --radius-lg: 20px;
  --radius-xl: 28px;
  --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: 'Inter', -apple-system, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
}

body::before {
  content: '';
  position: fixed; inset: 0;
  background: var(--gradient-bg);
  z-index: -1;
  pointer-events: none;
}

/* Typography */
h1, h2, h3, h4 { font-family: 'Space Grotesk', sans-serif; font-weight: 700; line-height: 1.15; }
h1 { font-size: clamp(2.2rem, 5vw, 3.8rem); letter-spacing: -0.03em; }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.4rem); letter-spacing: -0.02em; }
h3 { font-size: clamp(1.1rem, 2vw, 1.4rem); }
p { line-height: 1.7; color: var(--text-secondary); }

.text-gradient {
  background: var(--gradient-main);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ---- Navigation ---- */
.navbar {
  position: fixed; top: 0; left: 0; right: 0; z-index: 100;
  padding: 1rem 2rem;
  backdrop-filter: blur(20px) saturate(180%);
  background: rgba(10,14,26,0.75);
  border-bottom: 1px solid var(--border-subtle);
  transition: var(--transition);
}
.navbar-inner {
  max-width: 1280px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
}
.nav-logo {
  display: flex; align-items: center; gap: 0.6rem;
  text-decoration: none; color: var(--text-primary);
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 800; font-size: 1.4rem;
}
.nav-logo img { width: 36px; height: 36px; filter: drop-shadow(0 0 8px rgba(99,102,241,0.5)); }
.nav-links { display: flex; gap: 2rem; list-style: none; align-items: center; }
.nav-links a {
  text-decoration: none; color: var(--text-secondary); font-weight: 500;
  font-size: 0.9rem; transition: var(--transition); position: relative;
}
.nav-links a::after {
  content: ''; position: absolute; bottom: -4px; left: 0;
  width: 0; height: 2px; background: var(--gradient-main);
  transition: var(--transition);
}
.nav-links a:hover { color: var(--text-primary); }
.nav-links a:hover::after { width: 100%; }

.hamburger {
  display: none; background: none; border: none; cursor: pointer;
  flex-direction: column; gap: 5px; padding: 4px;
}
.hamburger span {
  display: block; width: 24px; height: 2px;
  background: var(--text-primary); border-radius: 2px;
  transition: var(--transition);
}

/* ---- Hero Section ---- */
.hero {
  min-height: 100vh; display: flex; align-items: center; justify-content: center;
  padding: 8rem 2rem 4rem; position: relative; overflow: hidden;
}
.hero-content {
  text-align: center; max-width: 800px; position: relative; z-index: 2;
}
.hero-badge {
  display: inline-flex; align-items: center; gap: 0.5rem;
  padding: 0.4rem 1rem; border-radius: 50px;
  background: rgba(99,102,241,0.1); border: 1px solid var(--border-accent);
  color: var(--accent-3); font-size: 0.8rem; font-weight: 600;
  margin-bottom: 1.5rem; text-transform: uppercase; letter-spacing: 0.08em;
}
.hero-badge img { width: 18px; height: 18px; }
.hero h1 { margin-bottom: 1.2rem; }
.hero p { font-size: 1.15rem; max-width: 600px; margin: 0 auto 2.5rem; }

.hero-orb {
  position: absolute; border-radius: 50%; filter: blur(80px); opacity: 0.4;
  animation: float 8s ease-in-out infinite;
}
.hero-orb-1 {
  width: 400px; height: 400px; top: 10%; left: -10%;
  background: rgba(99,102,241,0.3);
}
.hero-orb-2 {
  width: 300px; height: 300px; bottom: 10%; right: -5%;
  background: rgba(139,92,246,0.25);
  animation-delay: -3s;
}
.hero-orb-3 {
  width: 200px; height: 200px; top: 40%; right: 20%;
  background: rgba(6,182,212,0.2);
  animation-delay: -5s;
}

@keyframes float {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-30px) scale(1.05); }
}

/* Particles */
.particles-container {
  position: absolute; inset: 0; overflow: hidden; pointer-events: none; z-index: 1;
}
.particle {
  position: absolute; width: 3px; height: 3px; border-radius: 50%;
  background: rgba(99,102,241,0.5);
  animation: rise 6s linear infinite;
}
@keyframes rise {
  0% { transform: translateY(100vh) scale(0); opacity: 0; }
  20% { opacity: 1; }
  100% { transform: translateY(-20vh) scale(1); opacity: 0; }
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex; align-items: center; gap: 0.6rem;
  padding: 0.85rem 2rem; border-radius: var(--radius-md);
  font-family: 'Inter', sans-serif; font-weight: 600; font-size: 0.95rem;
  text-decoration: none; border: none; cursor: pointer;
  transition: var(--transition); position: relative; overflow: hidden;
}
.btn img { width: 20px; height: 20px; }
.btn-primary {
  background: var(--gradient-main); color: #fff;
  box-shadow: 0 4px 20px rgba(99,102,241,0.4);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(99,102,241,0.5);
}
.btn-secondary {
  background: var(--bg-glass); color: var(--text-primary);
  border: 1px solid var(--border-subtle);
  backdrop-filter: blur(10px);
}
.btn-secondary:hover {
  background: rgba(255,255,255,0.08);
  border-color: var(--border-accent);
  transform: translateY(-2px);
}
.btn-lg { padding: 1rem 2.5rem; font-size: 1.05rem; border-radius: var(--radius-lg); }
.btn-group { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }

/* ---- Sections ---- */
.section {
  padding: 6rem 2rem; max-width: 1280px; margin: 0 auto;
}
.section-header {
  text-align: center; margin-bottom: 3.5rem;
}
.section-header p {
  max-width: 560px; margin: 0.8rem auto 0;
}

/* ---- Module Cards ---- */
.modules-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 1.5rem;
}
.module-card {
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 2rem;
  backdrop-filter: blur(10px);
  transition: var(--transition);
  cursor: pointer; position: relative; overflow: hidden;
}
.module-card::before {
  content: ''; position: absolute; inset: 0;
  background: linear-gradient(135deg, rgba(99,102,241,0.05), transparent 60%);
  opacity: 0; transition: var(--transition);
}
.module-card:hover {
  transform: translateY(-6px);
  border-color: var(--border-accent);
  box-shadow: var(--shadow-glow);
}
.module-card:hover::before { opacity: 1; }

.module-icon {
  width: 64px; height: 64px; border-radius: var(--radius-md);
  display: flex; align-items: center; justify-content: center;
  margin-bottom: 1.2rem; font-size: 2rem;
  background: rgba(99,102,241,0.1);
}
.module-icon img { width: 40px; height: 40px; }
.module-card h3 { margin-bottom: 0.6rem; position: relative; z-index: 1; }
.module-card p { font-size: 0.9rem; margin-bottom: 1.2rem; position: relative; z-index: 1; }
.module-tags { display: flex; gap: 0.5rem; flex-wrap: wrap; position: relative; z-index: 1; }
.tag {
  padding: 0.25rem 0.7rem; border-radius: 50px;
  font-size: 0.72rem; font-weight: 600;
  background: rgba(99,102,241,0.1); color: var(--accent-3);
  border: 1px solid rgba(99,102,241,0.15);
}

/* ---- Features Section ---- */
.features-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 1.5rem;
}
.feature-card {
  background: var(--bg-glass); border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg); padding: 2rem;
  transition: var(--transition); text-align: center;
}
.feature-card:hover {
  border-color: var(--border-accent);
  transform: translateY(-4px);
  background: rgba(255,255,255,0.06);
}
.feature-icon {
  width: 56px; height: 56px; margin: 0 auto 1rem;
  display: flex; align-items: center; justify-content: center;
  border-radius: var(--radius-md);
  background: rgba(99,102,241,0.1);
}
.feature-icon img { width: 32px; height: 32px; }
.feature-card h3 { margin-bottom: 0.5rem; font-size: 1.1rem; }
.feature-card p { font-size: 0.88rem; }

/* ---- Steps / How it works ---- */
.steps-container {
  display: flex; flex-direction: column; gap: 2rem;
  max-width: 700px; margin: 0 auto;
}
.step {
  display: flex; gap: 1.5rem; align-items: flex-start;
  padding: 1.5rem; border-radius: var(--radius-lg);
  background: var(--bg-glass); border: 1px solid var(--border-subtle);
  transition: var(--transition);
}
.step:hover { border-color: var(--border-accent); }
.step-number {
  min-width: 48px; height: 48px; border-radius: 50%;
  background: var(--gradient-main);
  display: flex; align-items: center; justify-content: center;
  font-family: 'Space Grotesk', sans-serif;
  font-weight: 800; font-size: 1.2rem; color: #fff;
  flex-shrink: 0;
}
.step h3 { margin-bottom: 0.3rem; font-size: 1.05rem; }
.step p { font-size: 0.88rem; }

/* ---- Demo Banner ---- */
.demo-banner {
  background: var(--gradient-main);
  border-radius: var(--radius-xl);
  padding: 3.5rem 2.5rem;
  text-align: center;
  position: relative; overflow: hidden;
  margin: 2rem 0;
}
.demo-banner h2 { color: #fff; margin-bottom: 0.8rem; }
.demo-banner p { color: rgba(255,255,255,0.85); margin-bottom: 2rem; max-width: 500px; margin-left: auto; margin-right: auto; }
.demo-banner .btn {
  background: #fff; color: var(--accent-1);
  box-shadow: 0 4px 20px rgba(0,0,0,0.2);
}
.demo-banner .btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 30px rgba(0,0,0,0.3);
}

/* ---- Footer ---- */
.footer {
  border-top: 1px solid var(--border-subtle);
  padding: 3rem 2rem 2rem;
  text-align: center;
}
.footer-inner {
  max-width: 1280px; margin: 0 auto;
}
.footer p { font-size: 0.82rem; color: var(--text-muted); }
.footer a { color: var(--accent-3); text-decoration: none; }
.footer a:hover { text-decoration: underline; }
.footer-links { display: flex; gap: 1.5rem; justify-content: center; margin-bottom: 1rem; }
.footer-links a { font-size: 0.85rem; color: var(--text-secondary); }

/* ---- AR Page Specific ---- */
.ar-overlay {
  position: fixed; inset: 0; z-index: 1000;
  pointer-events: none;
}
.ar-hud {
  position: fixed; bottom: 0; left: 0; right: 0; z-index: 1001;
  padding: 1.5rem;
  background: linear-gradient(to top, rgba(0,0,0,0.8) 0%, transparent 100%);
}
.ar-hud-inner {
  max-width: 600px; margin: 0 auto;
  display: flex; align-items: center; justify-content: space-between;
}
.ar-btn {
  width: 52px; height: 52px; border-radius: 50%;
  border: 2px solid rgba(255,255,255,0.3);
  background: rgba(255,255,255,0.1);
  backdrop-filter: blur(10px);
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; transition: var(--transition);
  color: #fff; font-size: 1.2rem;
}
.ar-btn:hover {
  background: rgba(255,255,255,0.2);
  border-color: rgba(255,255,255,0.5);
}
.ar-btn-primary {
  width: 64px; height: 64px;
  background: var(--gradient-main);
  border: 3px solid rgba(255,255,255,0.5);
  box-shadow: 0 0 20px rgba(99,102,241,0.5);
}

.ar-info-panel {
  position: fixed; left: 1rem; top: 50%; transform: translateY(-50%);
  z-index: 1001; max-width: 260px;
  background: rgba(10,14,26,0.85);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 1.5rem;
  transition: var(--transition);
  opacity: 0; pointer-events: none;
}
.ar-info-panel.active { opacity: 1; pointer-events: all; }
.ar-info-panel h3 { font-size: 1rem; margin-bottom: 0.5rem; }
.ar-info-panel p { font-size: 0.82rem; }

/* ---- Module Selector (AR page) ---- */
.module-selector {
  position: fixed; top: 1rem; left: 50%; transform: translateX(-50%);
  z-index: 1001; display: flex; gap: 0.5rem;
  background: rgba(10,14,26,0.85);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border-subtle);
  border-radius: 50px; padding: 0.35rem;
}
.module-tab {
  padding: 0.5rem 1.2rem; border-radius: 50px;
  border: none; background: transparent;
  color: var(--text-secondary); font-size: 0.82rem;
  font-weight: 600; cursor: pointer;
  transition: var(--transition);
  display: flex; align-items: center; gap: 0.4rem;
}
.module-tab img { width: 18px; height: 18px; }
.module-tab.active {
  background: var(--gradient-main); color: #fff;
}
.module-tab:hover:not(.active) {
  color: var(--text-primary);
  background: rgba(255,255,255,0.06);
}

/* ---- Onboarding Modal ---- */
.modal-overlay {
  position: fixed; inset: 0; z-index: 2000;
  background: rgba(0,0,0,0.7);
  backdrop-filter: blur(8px);
  display: flex; align-items: center; justify-content: center;
  padding: 2rem;
  opacity: 0; pointer-events: none;
  transition: var(--transition);
}
.modal-overlay.active { opacity: 1; pointer-events: all; }
.modal {
  background: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  max-width: 480px; width: 100%;
  padding: 2.5rem;
  text-align: center;
  transform: scale(0.9);
  transition: var(--transition);
}
.modal-overlay.active .modal { transform: scale(1); }
.modal-emoji { font-size: 3.5rem; margin-bottom: 1rem; display: block; }
.modal-emoji img { width: 72px; height: 72px; }
.modal h2 { margin-bottom: 0.6rem; }
.modal p { margin-bottom: 1.5rem; }

/* ---- Loading Spinner ---- */
.loader {
  width: 48px; height: 48px; border-radius: 50%;
  border: 3px solid var(--border-subtle);
  border-top-color: var(--accent-1);
  animation: spin 0.8s linear infinite;
  margin: 2rem auto;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ---- Tooltip ---- */
.tooltip-3d {
  background: rgba(10,14,26,0.9);
  backdrop-filter: blur(10px);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-sm);
  padding: 0.6rem 1rem;
  color: var(--text-primary);
  font-size: 0.78rem;
  max-width: 200px;
  pointer-events: none;
  position: absolute;
  z-index: 100;
}

/* ---- Responsive ---- */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .hamburger { display: flex; }
  .nav-links.open {
    display: flex; flex-direction: column;
    position: absolute; top: 100%; left: 0; right: 0;
    background: rgba(10,14,26,0.95);
    backdrop-filter: blur(20px);
    padding: 1.5rem 2rem;
    border-bottom: 1px solid var(--border-subtle);
    gap: 1rem;
  }
  .hero { padding: 6rem 1.5rem 3rem; }
  .section { padding: 4rem 1.5rem; }
  .modules-grid { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr 1fr; }
  .demo-banner { padding: 2.5rem 1.5rem; }
  .ar-info-panel { left: 0.5rem; right: 0.5rem; max-width: 100%; top: auto; bottom: 120px; transform: none; }
  .module-selector { max-width: calc(100% - 2rem); overflow-x: auto; }
}

@media (max-width: 480px) {
  .features-grid { grid-template-columns: 1fr; }
  .btn-group { flex-direction: column; align-items: center; }
}

/* ---- Animations ---- */
.fade-in {
  opacity: 0; transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible { opacity: 1; transform: translateY(0); }

.stagger-1 { transition-delay: 0.1s; }
.stagger-2 { transition-delay: 0.2s; }
.stagger-3 { transition-delay: 0.3s; }
.stagger-4 { transition-delay: 0.4s; }

/* ---- 3D Preview Canvas ---- */
.preview-container {
  width: 100%; aspect-ratio: 16/10;
  border-radius: var(--radius-lg);
  overflow: hidden; position: relative;
  background: rgba(0,0,0,0.3);
  border: 1px solid var(--border-subtle);
  margin: 2rem 0;
}
.preview-container canvas { width: 100% !important; height: 100% !important; }

/* Scrollbar */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg-primary); }
::-webkit-scrollbar-thumb { background: var(--accent-1); border-radius: 3px; }