/* Navigation */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 56px;
  display: flex;
  align-items: center;
  background: rgba(8, 10, 15, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
  width: 100%;
}

.nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
  width: 100%;
}

.nav-logo {
  font-size: var(--text-lg);
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--color-text-primary);
  display: flex;
  align-items: center;
}

.nav-logo-accent {
  color: var(--color-accent);
}

.nav-links {
  display: flex;
  gap: var(--space-6);
  align-items: center;
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-base);
}

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

.nav-actions {
  display: flex;
  gap: var(--space-3);
  align-items: center;
}

.nav-mobile-toggle {
  display: none;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  color: var(--color-text-secondary);
}

/* Footer */
.footer {
  border-top: 1px solid var(--color-border);
  padding: 64px 0 32px;
  background: var(--color-bg-base);
  width: 100%;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

.footer-brand .footer-logo {
  margin-bottom: 16px;
}

.footer-brand p {
  color: var(--color-text-secondary);
  font-size: var(--text-sm);
  max-width: 240px;
  line-height: 1.6;
}

.footer-heading {
  font-size: var(--text-xs);
  color: var(--color-text-primary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-weight: 700;
  margin-bottom: 20px;
}

.footer-links {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-link {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  transition: color var(--transition-base);
}

.footer-link:hover {
  color: var(--color-text-primary);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  padding-top: 32px;
  border-top: 1px solid var(--color-border);
  gap: 32px;
}

.footer-copyright {
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  white-space: nowrap;
}

.footer-disclaimer {
  font-size: var(--text-xs);
  color: var(--color-text-muted);
  max-width: 800px;
  line-height: 1.5;
  text-align: right;
}

/* Page Header */
.page-header {
  padding: 32px 0 24px;
}

.page-header .breadcrumb {
  font-size: var(--text-xs);
  color: var(--color-text-secondary);
  margin-bottom: 8px;
  display: flex;
  gap: 6px;
  align-items: center;
}

.page-header .breadcrumb-separator {
  color: var(--color-text-muted);
}

.page-header h1 {
  font-size: var(--text-3xl);
  letter-spacing: -0.02em;
  font-weight: 700;
  margin-bottom: 8px;
  color: var(--color-text-primary);
}

.page-header .subtitle {
  font-size: var(--text-base);
  color: var(--color-text-secondary);
  max-width: 600px;
}

/* Upgrade Banner */
.upgrade-banner {
  background: var(--color-accent-muted);
  border: 1px solid rgba(99, 102, 241, 0.20);
  border-radius: var(--radius-lg);
  padding: 16px 24px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  margin: 24px 0;
}

.upgrade-banner-content {
  flex: 1;
}

.upgrade-banner-title {
  font-weight: 600;
  color: var(--color-text-primary);
  font-size: var(--text-base);
  margin-bottom: 4px;
}

.upgrade-banner-sub {
  color: var(--color-text-secondary);
  font-size: var(--text-xs);
}

/* Responsive */
@media (max-width: 1024px) {
  .footer-grid {
    grid-template-columns: 1.5fr 1fr 1fr;
    gap: 32px;
  }
}

@media (max-width: 767px) {
  .footer-grid {
    grid-template-columns: 1fr 1fr;
  }
  .footer-brand {
    grid-column: span 2;
  }
  .footer-bottom {
    flex-direction: column;
    align-items: center;
    text-align: center;
  }
  .footer-disclaimer {
    text-align: center;
  }
}

@media (max-width: 639px) {
  .nav-links {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 56px;
    left: 0;
    right: 0;
    background: var(--color-bg-base);
    border-bottom: 1px solid var(--color-border);
    padding: 16px var(--space-6);
    gap: 12px;
    z-index: 99;
  }
  
  .nav.open .nav-links {
    display: flex;
  }
  
  .nav-mobile-toggle {
    display: flex;
  }
  
  .nav-actions .btn-ghost {
    display: none;
  }
  
  .upgrade-banner {
    flex-direction: column;
    align-items: flex-start;
    gap: 16px;
  }
  
  .footer-grid {
    grid-template-columns: 1fr;
  }
  .footer-brand {
    grid-column: span 1;
  }
}

/* ════════════════════════ ARTICLE LAYOUT ════════════════════════ */
.article-layout { 
  display: grid; 
  grid-template-columns: 1fr 280px; 
  gap: 48px; 
  align-items: start; 
  margin-top: 32px; 
}
.article-body h2 { 
  font-size: 20px; 
  font-weight: 600; 
  letter-spacing: -0.02em; 
  margin: 40px 0 16px; 
  color: var(--color-text-primary); 
}
.article-body h3 {
  font-size: 17px;
  font-weight: 500;
  margin: 24px 0 12px;
  color: var(--color-text-primary);
}
.article-body p { 
  font-size: 15px; 
  line-height: 1.8; 
  color: var(--color-text-secondary); 
  margin-bottom: 20px; 
}
.article-body strong { 
  color: var(--color-text-primary); 
}
.article-body ul { 
  margin-bottom: 20px; 
  padding-left: 20px; 
  color: var(--color-text-secondary); 
  font-size: 15px; 
  line-height: 1.8; 
}
.article-body li { 
  margin-bottom: 8px; 
}

/* ════════════════════════ TOC SIDEBAR ════════════════════════ */
.toc { 
  position: sticky; 
  top: 80px; 
  background: var(--color-bg-surface); 
  border: 1px solid var(--color-border); 
  border-radius: var(--radius-lg); 
  padding: 20px; 
}
.toc-label { 
  font-size: 11px; 
  text-transform: uppercase; 
  letter-spacing: 0.08em; 
  color: var(--color-text-muted); 
  margin-bottom: 16px; 
  font-weight: 700; 
  display: flex;
  justify-content: space-between;
  align-items: center;
}
.toc-list { 
  list-style: none; 
  padding: 0; 
  margin: 0; 
  display: flex; 
  flex-direction: column; 
  gap: 8px; 
}
.toc a { 
  display: block; 
  font-size: 13px; 
  color: var(--color-text-muted); 
  padding: 4px 0; 
  border-left: 2px solid var(--color-border); 
  padding-left: 12px; 
  transition: color 150ms, border-color 150ms; 
  text-decoration: none; 
}
.toc a:hover, .toc a.active { 
  color: var(--color-text-primary); 
  border-color: var(--color-accent); 
}
.toc-chevron { display: none; }

/* Responsive TOC Accordion */
@media (max-width: 900px) { 
  .article-layout { grid-template-columns: 1fr; }
  .toc { position: static; margin-bottom: 32px; padding: 16px; }
  .toc-label { cursor: pointer; margin-bottom: 0; }
  .toc-chevron { display: block; width: 16px; height: 16px; transition: transform 0.2s; }
  .toc-list-container { display: none; margin-top: 16px; }
  .toc.open .toc-list-container { display: block; }
  .toc.open .toc-chevron { transform: rotate(180deg); }
}

/* ════════════════════════ TL;DR CARD ════════════════════════ */
.tldr-card { 
  background: var(--color-bg-surface); 
  border: 1px solid var(--color-border); 
  border-left: 3px solid var(--color-accent); 
  border-radius: var(--radius-lg); 
  padding: 24px; 
  margin: 32px 0; 
}
.tldr-label { 
  font-size: 12px; 
  font-weight: 700; 
  color: var(--color-accent); 
  letter-spacing: 0.05em; 
  margin-bottom: 12px; 
  text-transform: uppercase; 
}

/* ════════════════════════ FAQ ACCORDION ════════════════════════ */
.faq-section { 
  margin-top: 64px; 
  border-top: 1px solid var(--color-border); 
  padding-top: 40px; 
}
.faq-item { 
  border-bottom: 1px solid var(--color-border); 
  padding: 16px 0; 
}
.faq-question { 
  font-weight: 600; 
  color: var(--color-text-primary); 
  font-size: 16px; 
  margin-bottom: 8px; 
  cursor: pointer; 
  display: flex; 
  justify-content: space-between; 
  align-items: center; 
}
.faq-answer { 
  font-size: 15px; 
  color: var(--color-text-secondary); 
  line-height: 1.6; 
  display: none; 
  margin-top: 8px; 
}
.faq-item.open .faq-answer { display: block; }