/* ============================================
   SkillTesseract Landing Page — Styles
   ============================================ */

:root {
  --primary: #2563EB;
  --primary-hover: #1D4ED8;
  --primary-light: #EFF6FF;
  --indigo: #4F46E5;
  --green: #059669;
  --green-light: #ECFDF5;
  --amber: #D97706;
  --amber-light: #FFFBEB;
  --purple: #7C3AED;
  --purple-light: #F5F3FF;
  --rose: #E11D48;
  --rose-light: #FFF1F2;
  --gray-50: #F9FAFB;
  --gray-100: #F3F4F6;
  --gray-200: #E5E7EB;
  --gray-300: #D1D5DB;
  --gray-400: #9CA3AF;
  --gray-500: #6B7280;
  --gray-600: #4B5563;
  --gray-700: #374151;
  --gray-800: #1F2937;
  --gray-900: #111827;
  --gray-950: #030712;
  --white: #FFFFFF;
  --radius: 12px;
  --radius-lg: 16px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -2px rgba(0,0,0,0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.1), 0 4px 6px -4px rgba(0,0,0,0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.1), 0 8px 10px -6px rgba(0,0,0,0.1);

  /* Theme variables — light */
  --bg: var(--white);
  --bg-alt: var(--gray-50);
  --bg-card: var(--white);
  --text: var(--gray-900);
  --text-secondary: var(--gray-600);
  --text-muted: var(--gray-500);
  --text-faint: var(--gray-400);
  --border: var(--gray-100);
  --border-strong: var(--gray-200);
  --nav-bg: rgba(255, 255, 255, 0.85);
  --hero-gradient: linear-gradient(135deg, var(--primary-light) 0%, var(--white) 50%, #EEF2FF 100%);
  --hero-blob-1: rgba(37, 99, 235, 0.08);
  --hero-blob-2: rgba(79, 70, 229, 0.06);
  --icon-blue-bg: var(--primary-light);
  --icon-indigo-bg: #EEF2FF;
  --icon-green-bg: var(--green-light);
  --icon-amber-bg: var(--amber-light);
  --icon-purple-bg: var(--purple-light);
  --icon-rose-bg: var(--rose-light);
  --video-overlay: rgba(0, 0, 0, 0.4);
}

[data-theme="dark"] {
  --bg: var(--gray-950);
  --bg-alt: var(--gray-900);
  --bg-card: var(--gray-900);
  --text: var(--gray-100);
  --text-secondary: var(--gray-400);
  --text-muted: var(--gray-400);
  --text-faint: var(--gray-500);
  --border: var(--gray-800);
  --border-strong: var(--gray-700);
  --nav-bg: rgba(3, 7, 18, 0.85);
  --hero-gradient: linear-gradient(135deg, #0c1a3a 0%, var(--gray-950) 50%, #0f0d2e 100%);
  --hero-blob-1: rgba(37, 99, 235, 0.15);
  --hero-blob-2: rgba(79, 70, 229, 0.12);
  --icon-blue-bg: rgba(37, 99, 235, 0.15);
  --icon-indigo-bg: rgba(79, 70, 229, 0.15);
  --icon-green-bg: rgba(5, 150, 105, 0.15);
  --icon-amber-bg: rgba(217, 119, 6, 0.15);
  --icon-purple-bg: rgba(124, 58, 237, 0.15);
  --icon-rose-bg: rgba(225, 29, 72, 0.15);
  --video-overlay: rgba(0, 0, 0, 0.6);
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.3);
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.4), 0 2px 4px -2px rgba(0,0,0,0.3);
  --shadow-lg: 0 10px 15px -3px rgba(0,0,0,0.4), 0 4px 6px -4px rgba(0,0,0,0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0,0,0,0.5), 0 8px 10px -6px rgba(0,0,0,0.4);
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
  color: var(--text);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s, color 0.3s;
}

img, video {
  max-width: 100%;
  display: block;
}

a {
  text-decoration: none;
  color: inherit;
}

/* Container */
.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ============================================
   Navigation
   ============================================ */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--nav-bg);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  transition: box-shadow 0.3s, background-color 0.3s;
}

.navbar.scrolled {
  box-shadow: var(--shadow-sm);
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  font-weight: 700;
  font-size: 1.25rem;
  color: var(--text);
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 32px;
}

.nav-links a {
  font-size: 0.875rem;
  color: var(--text-secondary);
  transition: color 0.2s;
}

.nav-links a:hover {
  color: var(--text);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.mobile-menu-btn {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 4px;
}

.mobile-menu-btn span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text-secondary);
  border-radius: 2px;
  transition: transform 0.3s, opacity 0.3s;
}

/* ============================================
   Buttons
   ============================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-weight: 600;
  font-size: 0.875rem;
  border-radius: 8px;
  border: none;
  cursor: pointer;
  transition: all 0.2s;
  text-decoration: none;
  white-space: nowrap;
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.8125rem;
}

.btn-lg {
  padding: 16px 32px;
  font-size: 1rem;
}

.btn-primary {
  background: var(--primary);
  color: var(--white);
  box-shadow: var(--shadow-sm);
}

.btn-primary:hover {
  background: var(--primary-hover);
  box-shadow: var(--shadow);
  transform: translateY(-1px);
}

.btn-outline {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--border-strong);
}

.btn-outline:hover {
  background: var(--bg-alt);
  border-color: var(--text-faint);
}

.btn-white {
  background: var(--white);
  color: var(--primary);
  box-shadow: var(--shadow-sm);
}

.btn-white:hover {
  background: var(--gray-50);
  transform: translateY(-1px);
  box-shadow: var(--shadow);
}

.btn-outline-white {
  background: transparent;
  color: var(--white);
  border: 1px solid rgba(255,255,255,0.4);
}

.btn-outline-white:hover {
  background: rgba(255,255,255,0.1);
  border-color: rgba(255,255,255,0.7);
}

.btn-block {
  display: block;
  width: 100%;
  text-align: center;
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
  position: relative;
  overflow: hidden;
  padding: 100px 0 120px;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background: var(--hero-gradient);
  transition: background 0.3s;
}

.hero-blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(80px);
}

.hero-blob-1 {
  width: 500px;
  height: 500px;
  background: var(--hero-blob-1);
  top: -200px;
  right: -100px;
}

.hero-blob-2 {
  width: 350px;
  height: 350px;
  background: var(--hero-blob-2);
  bottom: -100px;
  left: -50px;
}

.hero-content {
  position: relative;
  text-align: center;
  max-width: 800px;
  margin: 0 auto;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  border-radius: 50px;
  background: var(--icon-blue-bg);
  border: 1px solid var(--primary);
  border-color: rgba(37, 99, 235, 0.3);
  color: var(--primary);
  font-size: 0.8125rem;
  font-weight: 500;
  margin-bottom: 32px;
}

[data-theme="dark"] .hero-badge {
  color: #93C5FD;
}

.badge-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--primary);
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.4; }
}

.hero h1 {
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  color: var(--text);
  margin-bottom: 24px;
}

.gradient-text {
  background: linear-gradient(135deg, var(--primary), var(--indigo));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-secondary);
  line-height: 1.7;
  max-width: 640px;
  margin: 0 auto 40px;
}

.hero-ctas {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 16px;
}

/* ============================================
   Section Shared Styles
   ============================================ */
.section-header {
  text-align: center;
  max-width: 600px;
  margin: 0 auto 60px;
}

.section-header h2 {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--text);
  letter-spacing: -0.02em;
  margin-bottom: 12px;
}

.section-header p {
  font-size: 1.0625rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ============================================
   Demo Video Section
   ============================================ */
.demo-section {
  padding: 100px 0;
  background: var(--bg);
}

.video-wrapper {
  position: relative;
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-xl);
  border: 1px solid var(--border-strong);
  background: #000;
  aspect-ratio: 16 / 9;
}

.video-wrapper video,
.video-wrapper iframe {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.video-overlay {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  background: var(--video-overlay);
  cursor: pointer;
  transition: background 0.3s;
}

.video-overlay:hover {
  background: rgba(0, 0, 0, 0.3);
}

.video-overlay.hidden {
  display: none;
}

.play-btn {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.95);
  border: none;
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: transform 0.2s, box-shadow 0.2s;
  box-shadow: var(--shadow-lg);
  color: var(--primary);
}

.play-btn:hover {
  transform: scale(1.08);
  box-shadow: var(--shadow-xl);
}

.video-label {
  color: var(--white);
  font-size: 0.875rem;
  font-weight: 500;
}

/* ============================================
   Features Section
   ============================================ */
.features-section {
  padding: 100px 0;
  background: var(--bg-alt);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  padding: 32px;
  transition: box-shadow 0.3s, transform 0.2s;
}

.feature-card:hover {
  box-shadow: var(--shadow-lg);
  transform: translateY(-2px);
}

.feature-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

.icon-blue { background: var(--icon-blue-bg); color: var(--primary); }
.icon-indigo { background: var(--icon-indigo-bg); color: var(--indigo); }
.icon-green { background: var(--icon-green-bg); color: var(--green); }
.icon-amber { background: var(--icon-amber-bg); color: var(--amber); }
.icon-purple { background: var(--icon-purple-bg); color: var(--purple); }
.icon-rose { background: var(--icon-rose-bg); color: var(--rose); }

.feature-card h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ============================================
   Versions Section
   ============================================ */
.versions-section {
  padding: 100px 0;
  background: var(--bg);
}

.versions-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  max-width: 900px;
  margin: 0 auto;
}

.version-card {
  position: relative;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-lg);
  padding: 40px 32px;
  background: var(--bg-card);
  transition: box-shadow 0.3s;
}

.version-card:hover {
  box-shadow: var(--shadow-lg);
}

.version-card-premium {
  border-color: var(--primary);
  box-shadow: 0 0 0 1px var(--primary), var(--shadow);
}

.version-badge {
  position: absolute;
  top: -12px;
  left: 32px;
  background: var(--primary);
  color: var(--white);
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 50px;
}

.version-badge-budget {
  background: var(--green);
}

.version-card h3 {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text);
  margin-bottom: 4px;
}

.version-url {
  font-size: 0.8125rem;
  color: var(--text-faint);
  font-family: monospace;
  margin-bottom: 16px;
}

.version-description {
  font-size: 0.9375rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin-bottom: 24px;
}

.version-features {
  list-style: none;
  margin-bottom: 32px;
}

.version-features li {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.9375rem;
  color: var(--text-secondary);
  padding: 8px 0;
}

.version-features li svg {
  color: var(--primary);
  flex-shrink: 0;
}

.version-card:not(.version-card-premium) .version-features li svg {
  color: var(--green);
}

/* ============================================
   How It Works Section
   ============================================ */
.how-it-works-section {
  padding: 100px 0;
  background: var(--bg-alt);
}

.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
}

.step {
  text-align: center;
}

.step-number {
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: var(--primary);
  color: var(--white);
  font-size: 1.5rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
}

.step h3 {
  font-size: 1.25rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 8px;
}

.step p {
  font-size: 0.9375rem;
  color: var(--text-muted);
  line-height: 1.6;
}

/* ============================================
   CTA Section
   ============================================ */
.cta-section {
  padding: 100px 0;
  background: linear-gradient(135deg, var(--primary) 0%, var(--indigo) 100%);
}

.cta-content {
  text-align: center;
  max-width: 700px;
  margin: 0 auto;
}

.cta-content h2 {
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: 12px;
}

.cta-content > p {
  font-size: 1.0625rem;
  color: rgba(255,255,255,0.8);
  margin-bottom: 36px;
}

.cta-buttons {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 24px;
}

.cta-contact {
  font-size: 0.875rem;
  color: rgba(255,255,255,0.7);
}

.cta-contact a {
  color: var(--white);
  text-decoration: underline;
  text-underline-offset: 2px;
}

.cta-contact a:hover {
  opacity: 0.9;
}

/* ============================================
   Footer
   ============================================ */
.footer {
  padding: 60px 0 32px;
  border-top: 1px solid var(--border-strong);
  background: var(--bg);
}

.footer-content {
  display: flex;
  flex-direction: column;
  gap: 40px;
}

.footer-brand {
  max-width: 280px;
}

.footer-brand .logo {
  display: inline-block;
  margin-bottom: 12px;
}

.footer-brand p {
  font-size: 0.875rem;
  color: var(--text-muted);
  line-height: 1.6;
}

.footer-links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.footer-col h4 {
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 16px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.footer-col a {
  display: block;
  font-size: 0.875rem;
  color: var(--text-muted);
  padding: 4px 0;
  transition: color 0.2s;
}

.footer-col a:hover {
  color: var(--text);
}

.footer-bottom {
  padding-top: 32px;
  border-top: 1px solid var(--border);
}

.footer-bottom p {
  font-size: 0.8125rem;
  color: var(--text-faint);
}

/* ============================================
   Theme Toggle
   ============================================ */
.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background: var(--bg-card);
  display: flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: background 0.2s, border-color 0.2s;
  color: var(--text-secondary);
}

.theme-toggle:hover {
  background: var(--bg-alt);
  border-color: var(--text-faint);
}

.theme-toggle .icon-sun,
.theme-toggle .icon-moon {
  width: 18px;
  height: 18px;
}

.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: block; }

[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

/* ============================================
   Responsive
   ============================================ */
@media (max-width: 1024px) {
  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 768px) {
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 12px;
    box-shadow: var(--shadow);
  }

  .nav-links.active {
    display: flex;
  }

  .nav-actions .btn {
    display: none;
  }

  .mobile-menu-btn {
    display: flex;
  }

  .hero {
    padding: 60px 0 80px;
  }

  .hero h1 {
    font-size: 2.25rem;
  }

  .hero-subtitle {
    font-size: 1rem;
  }

  .hero-ctas {
    flex-direction: column;
  }

  .hero-ctas .btn {
    width: 100%;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .versions-grid {
    grid-template-columns: 1fr;
  }

  .steps-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }

  .footer-links {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .section-header h2 {
    font-size: 1.75rem;
  }

  .cta-content h2 {
    font-size: 1.75rem;
  }

  .cta-buttons {
    flex-direction: column;
  }

  .cta-buttons .btn {
    width: 100%;
  }

  .demo-section,
  .features-section,
  .versions-section,
  .how-it-works-section,
  .cta-section {
    padding: 64px 0;
  }
}

@media (max-width: 480px) {
  .hero h1 {
    font-size: 1.875rem;
  }

  .container {
    padding: 0 16px;
  }

  .version-card {
    padding: 28px 20px;
  }
}