/* ==================== CSS VARIABLES ==================== */
:root {
  --accent: #4A90D9;
  --accent-hover: #3a7bc8;
  --accent-light: rgba(74, 144, 217, 0.1);
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-card: #ffffff;
  --text-primary: #1a1a2e;
  --text-secondary: #6b7280;
  --border: #e5e7eb;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.08);
  --radius: 12px;
  --radius-sm: 8px;
  --radius-lg: 16px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --border: #334155;
    --shadow: 0 1px 3px rgba(0, 0, 0, 0.3);
    --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.3);
  }
}

/* ==================== RESET & BASE ==================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 80px;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

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

/* ==================== UTILITIES ==================== */
.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 24px;
}

.gradient-text {
  background: linear-gradient(135deg, var(--accent), #7c3aed);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  text-align: center;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  text-align: center;
  color: var(--text-secondary);
  font-size: 1.125rem;
  max-width: 560px;
  margin: 0 auto 48px;
}

/* ==================== BUTTONS ==================== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-family: inherit;
  font-weight: 600;
  font-size: 1rem;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
  white-space: nowrap;
}

.btn-primary {
  background: var(--accent);
  color: #fff;
  padding: 12px 24px;
}

.btn-primary:hover {
  background: var(--accent-hover);
  transform: translateY(-1px);
  box-shadow: 0 4px 12px rgba(74, 144, 217, 0.4);
}

.btn-outline {
  background: transparent;
  color: var(--text-primary);
  padding: 12px 24px;
  border: 2px solid var(--border);
}

.btn-outline:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.btn-sm {
  padding: 8px 16px;
  font-size: 0.875rem;
}

.btn-lg {
  padding: 16px 32px;
  font-size: 1.125rem;
}

.btn-block {
  width: 100%;
  justify-content: center;
}

/* ==================== NAVBAR ==================== */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 1000;
  background: var(--bg-primary);
  transition: box-shadow 0.3s ease, background 0.3s ease;
}

.navbar.scrolled {
  box-shadow: 0 1px 12px rgba(0, 0, 0, 0.1);
}

@media (prefers-color-scheme: dark) {
  .navbar.scrolled {
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(12px);
  }
}

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

.navbar-brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 1.2rem;
}

.navbar-logo {
  flex-shrink: 0;
}

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

.navbar-links a:not(.btn) {
  color: var(--text-secondary);
  font-weight: 500;
  font-size: 0.9rem;
  transition: color 0.2s;
}

.navbar-links a:not(.btn):hover {
  color: var(--text-primary);
}

.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: 24px;
  height: 2px;
  background: var(--text-primary);
  border-radius: 2px;
  transition: all 0.3s ease;
}

.mobile-menu-btn.active span:nth-child(1) {
  transform: rotate(45deg) translate(5px, 5px);
}

.mobile-menu-btn.active span:nth-child(2) {
  opacity: 0;
}

.mobile-menu-btn.active span:nth-child(3) {
  transform: rotate(-45deg) translate(5px, -5px);
}

/* ==================== HERO ==================== */
.hero {
  padding: 120px 0 80px;
  background: var(--bg-primary);
  overflow: hidden;
}

.hero-inner {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.hero-title {
  font-size: 3.25rem;
  font-weight: 800;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-secondary);
  line-height: 1.7;
  margin-bottom: 32px;
  max-width: 480px;
}

.hero-cta {
  margin-bottom: 40px;
}

.hero-platforms {
  display: flex;
  align-items: center;
  gap: 16px;
}

.hero-platforms-label {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.platform-icons {
  display: flex;
  gap: 12px;
}

.platform-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  transition: all 0.2s;
}

.platform-icon:hover {
  background: var(--accent-light);
  color: var(--accent);
  transform: translateY(-2px);
}

/* Hero Mockup */
.hero-visual {
  display: flex;
  justify-content: center;
}

.mockup {
  width: 100%;
  max-width: 380px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}

.mockup-header {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-secondary);
}

.mockup-dots {
  display: flex;
  gap: 6px;
}

.mockup-dots span {
  width: 10px;
  height: 10px;
  border-radius: 50%;
}

.mockup-dots span:nth-child(1) { background: #ef4444; }
.mockup-dots span:nth-child(2) { background: #eab308; }
.mockup-dots span:nth-child(3) { background: #22c55e; }

.mockup-title {
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.mockup-body {
  padding: 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.mockup-folder {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  font-weight: 500;
  cursor: default;
  transition: background 0.2s;
}

.mockup-folder:hover {
  background: var(--bg-secondary);
}

.mockup-folder-icon {
  font-size: 1rem;
}

.mockup-badge {
  margin-left: auto;
  background: var(--bg-secondary);
  color: var(--text-secondary);
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 10px;
}

.mockup-folder-blue { border-left: 3px solid #4A90D9; }
.mockup-folder-green { border-left: 3px solid #22c55e; }
.mockup-folder-purple { border-left: 3px solid #8b5cf6; }
.mockup-folder-orange { border-left: 3px solid #f97316; }

.mockup-chat {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  font-size: 0.8rem;
  color: var(--text-secondary);
}

.mockup-chat-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--text-secondary);
  opacity: 0.4;
  flex-shrink: 0;
}

/* ==================== PLATFORMS ==================== */
.platforms {
  padding: 80px 0;
  background: var(--bg-secondary);
}

.platform-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

.platform-card {
  text-align: center;
  padding: 32px 20px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all 0.3s ease;
}

.platform-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.platform-card-icon {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 16px;
}

.platform-chatgpt { background: #10a37f20; color: #10a37f; }
.platform-claude { background: #d4a27420; color: #d4a274; }
.platform-gemini { background: #4285f420; color: #4285f4; }
.platform-grok { background: #1d9bf020; color: #1d9bf0; }

.platform-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.platform-card p {
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

/* ==================== FEATURES ==================== */
.features {
  padding: 80px 0;
}

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

.feature-card {
  padding: 32px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: all 0.3s ease;
}

.feature-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.feature-icon {
  font-size: 2rem;
  margin-bottom: 16px;
}

.feature-card h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

.badge {
  display: inline-block;
  background: var(--accent-light);
  color: var(--accent);
  font-size: 0.65rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  vertical-align: middle;
}

/* ==================== HOW IT WORKS ==================== */
.how-it-works {
  padding: 80px 0;
  background: var(--bg-secondary);
}

.steps {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 40px;
  margin-top: 48px;
}

.step {
  text-align: center;
  position: relative;
}

.step-number {
  position: absolute;
  top: -12px;
  right: calc(50% - 56px);
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-size: 0.8rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
}

.step-icon {
  width: 80px;
  height: 80px;
  border-radius: 50%;
  background: var(--accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0 auto 20px;
}

.step h3 {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.step p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
  max-width: 260px;
  margin: 0 auto;
}

/* ==================== PRICING ==================== */
.pricing {
  padding: 80px 0;
}

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
  max-width: 1000px;
  margin: 0 auto;
}

.pricing-card {
  padding: 40px 32px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  position: relative;
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
}

.pricing-card .pricing-features {
  flex: 1;
}

.pricing-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-lg);
}

.pricing-card-featured {
  border-color: var(--accent);
  box-shadow: 0 0 0 1px var(--accent);
}

.pricing-popular {
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
  background: var(--accent);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 16px;
  border-radius: 20px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.pricing-header {
  margin-bottom: 24px;
}

.pricing-header h3 {
  font-size: 1.3rem;
  font-weight: 700;
  margin-bottom: 8px;
}

.pricing-price {
  display: flex;
  align-items: baseline;
  gap: 4px;
}

.price-amount {
  font-size: 3rem;
  font-weight: 800;
  letter-spacing: -0.02em;
}

.price-period {
  font-size: 1rem;
  color: var(--text-secondary);
}

.pricing-annual {
  margin-top: 4px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.save-badge {
  background: #22c55e20;
  color: #16a34a;
  font-size: 0.7rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 20px;
  margin-left: 4px;
}

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

.pricing-features li {
  padding: 8px 0;
  font-size: 0.9rem;
  display: flex;
  align-items: center;
  gap: 10px;
}

.pricing-features li.disabled {
  color: var(--text-secondary);
  opacity: 0.5;
}

.check {
  color: #22c55e;
  font-weight: 700;
  flex-shrink: 0;
}

.cross {
  color: #ef4444;
  opacity: 0.5;
  flex-shrink: 0;
}

/* ==================== COMPARISON ==================== */
.comparison {
  padding: 80px 0;
  background: var(--bg-secondary);
}

.table-wrapper {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-card);
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border);
}

.comparison-table th,
.comparison-table td {
  padding: 16px 20px;
  text-align: left;
  font-size: 0.9rem;
  border-bottom: 1px solid var(--border);
}

.comparison-table th {
  background: var(--bg-secondary);
  font-weight: 700;
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-secondary);
}

.comparison-table th.highlight {
  color: var(--accent);
}

.comparison-table td.highlight {
  background: var(--accent-light);
}

.comparison-table tbody tr:last-child td {
  border-bottom: none;
}

/* ==================== FAQ ==================== */
.faq {
  padding: 80px 0;
}

.faq-list {
  max-width: 720px;
  margin: 0 auto;
}

.faq-item {
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  margin-bottom: 12px;
  overflow: hidden;
  background: var(--bg-card);
}

.faq-question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 18px 20px;
  background: none;
  border: none;
  cursor: pointer;
  font-family: inherit;
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: left;
  transition: color 0.2s;
}

.faq-question:hover {
  color: var(--accent);
}

.faq-chevron {
  flex-shrink: 0;
  transition: transform 0.3s ease;
  color: var(--text-secondary);
}

.faq-item.active .faq-chevron {
  transform: rotate(180deg);
}

.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.3s ease;
}

.faq-answer p {
  padding: 0 20px 18px;
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.7;
}

/* ==================== FINAL CTA ==================== */
.final-cta {
  padding: 80px 0;
  background: var(--bg-secondary);
}

.final-cta-inner {
  text-align: center;
  max-width: 560px;
  margin: 0 auto;
}

.final-cta h2 {
  font-size: 2.25rem;
  font-weight: 800;
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.final-cta p {
  font-size: 1.1rem;
  color: var(--text-secondary);
  margin-bottom: 32px;
}

/* ==================== FOOTER ==================== */
.footer {
  padding: 32px 0;
  border-top: 1px solid var(--border);
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.9rem;
}

.footer-links {
  display: flex;
  gap: 24px;
}

.footer-links a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  transition: color 0.2s;
}

.footer-links a:hover {
  color: var(--accent);
}

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-secondary);
}

/* ==================== ANIMATIONS ==================== */
.fade-in {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

/* ==================== RESPONSIVE ==================== */
@media (max-width: 1024px) {
  .hero-title {
    font-size: 2.5rem;
  }

  .hero-inner {
    gap: 40px;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .pricing-grid {
    grid-template-columns: 1fr 1fr;
    max-width: 700px;
  }

  .pricing-grid .pricing-card:first-child {
    grid-column: 1 / -1;
    max-width: 340px;
    margin: 0 auto;
  }
}

@media (max-width: 768px) {
  .mobile-menu-btn {
    display: flex;
  }

  .navbar-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--bg-primary);
    flex-direction: column;
    padding: 20px 24px;
    gap: 16px;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
  }

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

  .navbar-links .btn {
    width: 100%;
    justify-content: center;
  }

  .hero {
    padding: 100px 0 60px;
  }

  .hero-inner {
    grid-template-columns: 1fr;
    gap: 40px;
    text-align: center;
  }

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

  .hero-subtitle {
    margin-left: auto;
    margin-right: auto;
  }

  .hero-cta {
    display: flex;
    justify-content: center;
  }

  .hero-platforms {
    justify-content: center;
  }

  .hero-visual {
    order: -1;
  }

  .mockup {
    max-width: 320px;
  }

  .platform-grid {
    grid-template-columns: repeat(2, 1fr);
  }

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

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

  .pricing-grid {
    grid-template-columns: 1fr;
    max-width: 420px;
  }

  .section-title {
    font-size: 1.75rem;
  }

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

  .comparison-table th,
  .comparison-table td {
    padding: 12px 14px;
    font-size: 0.8rem;
  }

  .footer-inner {
    flex-direction: column;
    text-align: center;
  }

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

@media (max-width: 480px) {
  .hero-title {
    font-size: 1.85rem;
  }

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

  .btn-lg {
    padding: 14px 24px;
    font-size: 1rem;
  }
}