/* ==========================================================================
   AI Conversation Saver - Static Website Stylesheet
   Modern, zero-dependency, responsive styling
   ========================================================================== */

:root {
  --bg-primary: #09090b;
  --bg-secondary: #121215;
  --bg-tertiary: #18181b;
  --bg-card: #18181b;
  --bg-card-hover: #202024;
  --border-subtle: #27272a;
  --border-strong: #3f3f46;
  --text-primary: #fafafa;
  --text-secondary: #a1a1aa;
  --text-muted: #71717a;
  --accent-blue: #3b82f6;
  --accent-blue-hover: #2563eb;
  --accent-blue-subtle: rgba(59, 130, 246, 0.1);
  --accent-green: #10b981;
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --radius-full: 9999px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.4);
  --shadow-md: 0 4px 12px 0 rgba(0, 0, 0, 0.5);
  --shadow-lg: 0 12px 32px -4px rgba(0, 0, 0, 0.6);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;
}

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

html {
  font-family: var(--font-sans);
  background-color: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.6;
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  overflow-x: hidden;
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background-color: rgba(9, 9, 11, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-subtle);
}

.header-container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 72px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
}

.brand-logo-img {
  width: 34px;
  height: 34px;
  display: block;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.9rem;
  font-weight: 500;
  transition: color 0.15s ease;
}

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

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

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 8px 16px;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.15s ease;
  border: 1px solid transparent;
}

.btn-sm {
  padding: 6px 12px;
  font-size: 0.8rem;
}

.btn-lg {
  padding: 12px 24px;
  font-size: 1rem;
  border-radius: var(--radius-lg);
}

.btn-primary {
  background-color: var(--text-primary);
  color: var(--bg-primary);
}

.btn-primary:hover {
  background-color: #ffffff;
  box-shadow: 0 0 20px rgba(255, 255, 255, 0.2);
}

.btn-accent {
  background-color: var(--accent-blue);
  color: #ffffff;
}

.btn-accent:hover {
  background-color: var(--accent-blue-hover);
  box-shadow: 0 0 20px rgba(59, 130, 246, 0.35);
}

.btn-secondary {
  background-color: var(--bg-tertiary);
  color: var(--text-primary);
  border-color: var(--border-subtle);
}

.btn-secondary:hover {
  background-color: var(--bg-card-hover);
  border-color: var(--border-strong);
}

.btn-ghost {
  background-color: transparent;
  color: var(--text-secondary);
}

.btn-ghost:hover {
  color: var(--text-primary);
  background-color: rgba(255, 255, 255, 0.05);
}

/* ==========================================================================
   Common Layout Elements
   ========================================================================== */

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

.section {
  padding: 80px 0;
}

.section-hero {
  padding: 96px 0 64px 0;
  text-align: center;
  position: relative;
}

.section-heading {
  text-align: center;
  max-width: 680px;
  margin: 0 auto 56px auto;
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 12px;
  background-color: var(--accent-blue-subtle);
  border: 1px solid rgba(59, 130, 246, 0.25);
  border-radius: var(--radius-full);
  color: #93c5fd;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: 16px;
}

.section-title {
  font-size: 2.25rem;
  font-weight: 800;
  letter-spacing: -0.02em;
  color: var(--text-primary);
  margin-bottom: 16px;
  line-height: 1.2;
}

.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ==========================================================================
   Hero Section Details
   ========================================================================== */

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 16px;
  background-color: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-full);
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 500;
  margin-bottom: 24px;
}

.hero-badge-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background-color: var(--accent-green);
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 24px;
  max-width: 900px;
  margin-left: auto;
  margin-right: auto;
}

.hero-highlight {
  background: linear-gradient(135deg, #60a5fa 0%, #3b82f6 50%, #93c5fd 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.hero-subtitle {
  font-size: 1.2rem;
  color: var(--text-secondary);
  max-width: 720px;
  margin: 0 auto 36px auto;
  line-height: 1.6;
}

.hero-cta-group {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 16px;
  margin-bottom: 48px;
}

/* Extension Preview Mockup */
.preview-container {
  max-width: 960px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
  border: 1px solid var(--border-subtle);
  background-color: var(--bg-secondary);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  text-align: left;
}

.preview-bar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 18px;
  background-color: var(--bg-tertiary);
  border-bottom: 1px solid var(--border-subtle);
}

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

.preview-dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background-color: var(--border-strong);
}

.preview-title {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.preview-body {
  display: grid;
  grid-template-columns: 1fr 340px;
  min-height: 380px;
}

.preview-chat-area {
  padding: 24px;
  border-right: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.mock-msg {
  padding: 14px 16px;
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  max-width: 90%;
  position: relative;
}

.mock-msg-user {
  background-color: rgba(255, 255, 255, 0.05);
  align-self: flex-end;
  color: var(--text-primary);
}

.mock-msg-ai {
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  align-self: flex-start;
  color: var(--text-secondary);
  line-height: 1.5;
}

.mock-msg-marker {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  margin-top: 10px;
  padding: 4px 10px;
  background-color: var(--accent-blue-subtle);
  border: 1px solid rgba(59, 130, 246, 0.3);
  border-radius: var(--radius-sm);
  color: #93c5fd;
  font-size: 0.75rem;
  font-weight: 600;
}

.preview-sidepanel {
  background-color: var(--bg-primary);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.sidepanel-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
}

.sidepanel-title {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--text-primary);
}

.sidepanel-item {
  padding: 10px 12px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.sidepanel-item-tag {
  align-self: flex-start;
  padding: 2px 8px;
  border-radius: 4px;
  font-size: 0.65rem;
  font-weight: 700;
  text-transform: uppercase;
  background-color: rgba(255, 255, 255, 0.08);
  color: var(--text-secondary);
}

.sidepanel-item-text {
  font-size: 0.75rem;
  color: var(--text-primary);
  line-height: 1.4;
}

/* ==========================================================================
   Platform Support Bar
   ========================================================================== */

.platforms-bar {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 36px;
  padding: 24px;
  border-top: 1px solid var(--border-subtle);
  border-bottom: 1px solid var(--border-subtle);
  background-color: var(--bg-secondary);
}

.platform-item {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--text-secondary);
  font-size: 0.875rem;
  font-weight: 600;
}

.platform-icon {
  width: 22px;
  height: 22px;
}

/* ==========================================================================
   Features Grid
   ========================================================================== */

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

.feature-card {
  padding: 28px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  gap: 14px;
  transition: all 0.2s ease;
}

.feature-card:hover {
  background-color: var(--bg-card-hover);
  border-color: var(--border-strong);
  transform: translateY(-2px);
}

.feature-icon-wrapper {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background-color: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-blue);
}

.feature-title {
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--text-primary);
}

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

/* ==========================================================================
   Use Cases Section
   ========================================================================== */

.use-cases-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 24px;
}

.use-case-card {
  padding: 32px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  display: flex;
  gap: 20px;
}

.use-case-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-md);
  background-color: var(--accent-blue-subtle);
  border: 1px solid rgba(59, 130, 246, 0.2);
  display: flex;
  align-items: center;
  justify-content: center;
  color: #60a5fa;
  flex-shrink: 0;
}

.use-case-content h3 {
  font-size: 1.15rem;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--text-primary);
}

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

/* ==========================================================================
   Pricing Page Elements
   ========================================================================== */

.pricing-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
  max-width: 860px;
  margin: 0 auto;
}

.pricing-card {
  padding: 36px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  display: flex;
  flex-direction: column;
  position: relative;
}

.pricing-card.featured {
  border-color: var(--accent-blue);
  background: linear-gradient(180deg, rgba(37, 99, 235, 0.08) 0%, rgba(24, 24, 27, 1) 100%);
  box-shadow: 0 0 30px rgba(59, 130, 246, 0.15);
}

.pricing-badge {
  position: absolute;
  top: -12px;
  right: 28px;
  padding: 4px 12px;
  background-color: var(--accent-blue);
  color: #ffffff;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.plan-name {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 6px;
}

.plan-desc {
  font-size: 0.875rem;
  color: var(--text-secondary);
  margin-bottom: 24px;
  min-height: 42px;
}

.plan-price {
  display: flex;
  align-items: baseline;
  gap: 4px;
  margin-bottom: 28px;
}

.price-currency {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--text-primary);
}

.price-amount {
  font-size: 3rem;
  font-weight: 800;
  line-height: 1;
  color: var(--text-primary);
  letter-spacing: -0.03em;
}

.price-period {
  font-size: 0.875rem;
  color: var(--text-muted);
}

.plan-features-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 14px;
  margin-bottom: 32px;
  flex-grow: 1;
}

.plan-feature-item {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.check-icon {
  width: 16px;
  height: 16px;
  color: var(--accent-blue);
  flex-shrink: 0;
}

/* ==========================================================================
   Comparison Table
   ========================================================================== */

.comparison-section {
  max-width: 860px;
  margin: 64px auto 0 auto;
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 24px;
  font-size: 0.875rem;
}

.comparison-table th,
.comparison-table td {
  padding: 14px 18px;
  text-align: left;
  border-bottom: 1px solid var(--border-subtle);
}

.comparison-table th {
  color: var(--text-muted);
  font-weight: 600;
  font-size: 0.8rem;
  text-transform: uppercase;
}

.comparison-table td {
  color: var(--text-secondary);
}

.comparison-table tr:hover td {
  background-color: rgba(255, 255, 255, 0.02);
}

/* ==========================================================================
   Contact & About Page Elements
   ========================================================================== */

.contact-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
  max-width: 960px;
  margin: 0 auto;
}

.contact-card {
  padding: 32px;
  background-color: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
}

.contact-form {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

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

.form-input,
.form-textarea,
.form-select {
  padding: 10px 14px;
  border-radius: var(--radius-md);
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  color: var(--text-primary);
  font-size: 0.875rem;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s ease;
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  border-color: var(--accent-blue);
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

.info-cards {
  display: flex;
  flex-direction: column;
  gap: 18px;
}

.info-item {
  padding: 20px;
  background-color: var(--bg-secondary);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  display: flex;
  gap: 16px;
}

.info-icon {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-sm);
  background-color: rgba(255, 255, 255, 0.05);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--accent-blue);
  flex-shrink: 0;
}

/* ==========================================================================
   Footer
   ========================================================================== */

.site-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-subtle);
  background-color: var(--bg-secondary);
  padding: 56px 0 32px 0;
}

.footer-top {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  margin-bottom: 48px;
  flex-wrap: wrap;
  gap: 32px;
}

.footer-brand {
  max-width: 320px;
}

.footer-brand p {
  color: var(--text-muted);
  font-size: 0.875rem;
  margin-top: 12px;
  line-height: 1.5;
}

.footer-nav {
  display: flex;
  gap: 56px;
}

.footer-nav-col {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-nav-col h4 {
  font-size: 0.8rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-primary);
  letter-spacing: 0.05em;
}

.footer-nav-col a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.875rem;
  transition: color 0.15s ease;
}

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

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border-subtle);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 16px;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */

@media (max-width: 900px) {
  .features-grid {
    grid-template-columns: 1fr;
  }
  .use-cases-grid {
    grid-template-columns: 1fr;
  }
  .preview-body {
    grid-template-columns: 1fr;
  }
  .preview-sidepanel {
    border-top: 1px solid var(--border-subtle);
  }
  .pricing-grid {
    grid-template-columns: 1fr;
  }
  .contact-layout {
    grid-template-columns: 1fr;
  }
  .hero-title {
    font-size: 2.5rem;
  }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
  }
  .hero-cta-group {
    flex-direction: column;
    width: 100%;
  }
  .hero-cta-group .btn {
    width: 100%;
  }
  .footer-nav {
    flex-direction: column;
    gap: 24px;
  }
}