/* ==========================================================================
   Design DNA: D-00CBBD-00 (Archetype Structured Reference Hub)
   Color System: Deep Teal
   Typography: Type Compact Reference
   Layout System: Layout Asymmetric Editorial
   Navigation: Nav Sidebar Reference
   ========================================================================== */

:root {
  /* Typography definitions */
  --font-sans: 'SF Pro Text', 'Segoe UI', system-ui, -apple-system, BlinkMacSystemFont, 'Sukhumvit Set', 'Prompt', sans-serif;
  --font-serif: ui-serif, serif;
  --font-mono: ui-monospace, monospace;

  /* Color System: Color Deep Teal */
  --bg-page: #F0F4F4;
  --surface: #FFFFFF;
  --primary-text: #0F2929;
  --secondary-text: #4D6666;
  --accent: #0F766E;
  --border: #CCE0E0;
  --muted-bg: #E0EBEB;
  --interactive: #115E59;
  --interactive-hover: #0D4E49;
  --interactive-focus-ring: rgba(15, 118, 110, 0.35);

  /* Spacing Scale */
  --space-xxs: 0.25rem;
  --space-xs: 0.5rem;
  --space-sm: 0.75rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Layout dimensions */
  --sidebar-width: 290px;
  --header-height-mobile: 60px;
  --content-max-width: 1180px;
}

/* Bulletproof Reset & Box Sizing */
*, *::before, *::after {
  box-sizing: border-box;
}

html, body {
  overflow-x: hidden;
  width: 100%;
  margin: 0;
  padding: 0;
  background-color: var(--bg-page);
  color: var(--primary-text);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Typography Headings according to Type Compact Reference */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-sans);
  color: var(--primary-text);
  margin-top: 0;
  margin-bottom: var(--space-md);
  letter-spacing: -0.01em;
}

h1 {
  font-size: 2rem;
  line-height: 1.25;
  font-weight: 600;
}

h2 {
  font-size: 1.5rem;
  line-height: 1.25;
  font-weight: 600;
}

h3 {
  font-size: 1.25rem;
  line-height: 1.25;
  font-weight: 600;
}

h4 {
  font-size: 1.1rem;
  line-height: 1.3;
  font-weight: 600;
}

p {
  margin-top: 0;
  margin-bottom: var(--space-md);
  color: var(--primary-text);
  font-size: 1rem;
  line-height: 1.6;
}

p.lead {
  font-size: 1.125rem;
  line-height: 1.5;
  color: var(--secondary-text);
}

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

a {
  color: var(--accent);
  text-decoration: underline;
  text-underline-offset: 3px;
  transition: color 0.15s ease;
}

a:hover {
  color: var(--interactive-hover);
}

a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* Skip link */
.skip-link {
  position: absolute;
  top: -100px;
  left: 1rem;
  background: var(--accent);
  color: #FFFFFF;
  padding: 0.5rem 1rem;
  z-index: 9999;
  text-decoration: none;
  font-weight: 600;
  border-radius: 4px;
}
.skip-link:focus {
  top: 1rem;
}

/* Raw Semantic Container Rules: header, nav, main, footer */

/* Desktop Layout: Permanent Left Sidebar (nav-sidebar-reference) & Push Main */
@media (min-width: 1024px) {
  /* Sidebar Navigation */
  nav {
    position: fixed;
    top: 0;
    left: 0;
    width: var(--sidebar-width);
    height: 100vh;
    background-color: var(--surface);
    border-right: 1px solid var(--border);
    overflow-y: auto;
    z-index: 100;
    display: flex;
    flex-direction: column;
    padding: var(--space-xl) var(--space-lg);
  }

  /* Desktop Header: minimal top status / breadcrumb bar or branding */
  header {
    margin-left: var(--sidebar-width);
    background-color: var(--surface);
    border-bottom: 1px solid var(--border);
    padding: var(--space-md) var(--space-2xl);
    display: flex;
    justify-content: space-between;
    align-items: center;
  }

  /* Main Content Area */
  main {
    margin-left: var(--sidebar-width);
    min-height: 80vh;
    padding: var(--space-2xl) var(--space-2xl);
    background-color: var(--bg-page);
    display: block;
  }

  /* Footer */
  footer {
    margin-left: var(--sidebar-width);
    background-color: var(--primary-text);
    color: var(--bg-page);
    border-top: 1px solid var(--border);
    padding: var(--space-3xl) var(--space-2xl);
  }
}

/* Mobile & Tablet Layout (< 1024px) */
@media (max-width: 1023px) {
  header {
    position: sticky;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height-mobile);
    background-color: var(--surface);
    border-bottom: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0 var(--space-md);
    z-index: 500;
  }

  nav {
    position: fixed;
    top: var(--header-height-mobile);
    left: 0;
    width: 100%;
    height: calc(100vh - var(--header-height-mobile));
    background-color: var(--surface);
    border-right: none;
    overflow-y: auto;
    z-index: 499;
    padding: var(--space-lg) var(--space-md);
    transform: translateX(-100%);
    transition: transform 0.3s ease-in-out;
    display: flex;
    flex-direction: column;
  }

  nav.is-open {
    transform: translateX(0);
  }

  main {
    margin-left: 0;
    padding: var(--space-lg) var(--space-md);
    min-height: 70vh;
  }

  footer {
    margin-left: 0;
    background-color: var(--primary-text);
    color: var(--bg-page);
    padding: var(--space-2xl) var(--space-md);
  }
}

/* Sidebar Brand and Tree Nav Details */
.nav-brand {
  margin-bottom: var(--space-xl);
  padding-bottom: var(--space-md);
  border-bottom: 1px solid var(--border);
}

.nav-brand .site-logo {
  display: flex;
  align-items: center;
  gap: var(--space-xs);
  text-decoration: none;
  color: var(--primary-text);
  font-weight: 700;
  font-size: 1.15rem;
}

.nav-brand .site-badge {
  display: inline-block;
  margin-top: var(--space-xs);
  font-size: 0.75rem;
  background-color: var(--muted-bg);
  color: var(--accent);
  padding: 0.15rem 0.5rem;
  border-radius: 3px;
  font-weight: 600;
}

.nav-tree-group {
  margin-bottom: var(--space-lg);
}

.nav-tree-title {
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--secondary-text);
  font-weight: 700;
  margin-bottom: var(--space-xs);
  padding-left: var(--space-xs);
}

.nav-tree-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-tree-list li {
  margin-bottom: 2px;
}

.nav-tree-list a {
  display: block;
  padding: 0.45rem var(--space-xs);
  font-size: 0.875rem;
  color: var(--primary-text);
  text-decoration: none;
  border-radius: 4px;
  border-left: 2px solid transparent;
}

.nav-tree-list a:hover {
  background-color: var(--muted-bg);
  color: var(--accent);
}

.nav-tree-list a.active {
  background-color: var(--muted-bg);
  color: var(--interactive);
  border-left-color: var(--accent);
  font-weight: 600;
}

/* Mobile Nav Toggle Button */
.nav-toggle-btn {
  display: none;
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 0.4rem 0.6rem;
  color: var(--primary-text);
  cursor: pointer;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.875rem;
  font-family: inherit;
  min-height: 44px;
  min-width: 44px;
}

@media (max-width: 1023px) {
  .nav-toggle-btn {
    display: inline-flex;
  }
}

/* Header Elements */
.header-brand-mobile {
  display: none;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--primary-text);
  text-decoration: none;
}
@media (max-width: 1023px) {
  .header-brand-mobile {
    display: inline-block;
  }
}

.header-status-badge {
  font-size: 0.8125rem;
  color: var(--secondary-text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.header-status-badge::before {
  content: '';
  display: inline-block;
  width: 8px;
  height: 8px;
  background-color: #10B981;
  border-radius: 50%;
}

/* Asymmetric Editorial Layout System (layout-asymmetric-editorial) */
.layout-asymmetric {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
  max-width: var(--content-max-width);
}

@media (min-width: 1024px) {
  .layout-asymmetric {
    grid-template-columns: minmax(0, 7.5fr) minmax(0, 4.5fr);
    align-items: start;
    gap: var(--space-3xl);
  }
  
  .layout-asymmetric.wide-center {
    grid-template-columns: minmax(0, 8.5fr) minmax(0, 3.5fr);
  }
}

/* Sections Dense Modules (sections-dense-modules) */
section {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: var(--space-xl);
  margin-bottom: var(--space-xl);
}

section.dense-alt {
  background-color: var(--muted-bg);
}

.section-eyebrow {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  margin-bottom: var(--space-xs);
  display: block;
}

.section-header {
  border-bottom: 1px solid var(--border);
  padding-bottom: var(--space-md);
  margin-bottom: var(--space-lg);
}

/* Hero Text First Implementation (hero-text-first) */
.hero-text-first {
  background-color: var(--surface);
  border: 1px solid var(--border);
  padding: var(--space-2xl) var(--space-xl);
  margin-bottom: var(--space-2xl);
  border-radius: 4px;
  border-left: 4px solid var(--accent);
}

.hero-text-first h1 {
  font-size: 2.25rem;
  line-height: 1.2;
  margin-bottom: var(--space-md);
  color: var(--primary-text);
  max-width: 900px;
}

.hero-text-first p.hero-summary {
  font-size: 1.125rem;
  line-height: 1.5;
  color: var(--secondary-text);
  max-width: 800px;
  margin-bottom: var(--space-lg);
}

.hero-meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
  font-size: 0.8125rem;
  color: var(--secondary-text);
  border-top: 1px solid var(--border);
  padding-top: var(--space-md);
}

/* Single Photographic Asset Container */
.editorial-photo-wrap {
  margin: var(--space-lg) 0;
  border: 1px solid var(--border);
  border-radius: 4px;
  overflow: hidden;
  background-color: var(--muted-bg);
}

.editorial-photo-wrap img {
  width: 100%;
  max-height: 420px;
  object-fit: cover;
  display: block;
}

.editorial-photo-caption {
  padding: var(--space-xs) var(--space-md);
  font-size: 0.8125rem;
  color: var(--secondary-text);
  background-color: var(--surface);
  border-top: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

/* Card System: Cards Horizontal Reference */
.cards-horizontal-grid {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.card-horizontal {
  display: flex;
  flex-direction: column;
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: var(--space-lg);
  text-decoration: none;
  color: inherit;
  transition: border-color 0.15s ease, transform 0.15s ease;
}

@media (min-width: 768px) {
  .card-horizontal {
    flex-direction: row;
    align-items: flex-start;
    justify-content: space-between;
    gap: var(--space-lg);
  }
  .card-horizontal-main {
    flex: 1 1 auto;
  }
  .card-horizontal-side {
    flex: 0 0 180px;
    text-align: right;
  }
}

.card-horizontal:hover {
  border-color: var(--accent);
  background-color: #FAFCFC;
}

.card-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  background-color: var(--muted-bg);
  padding: 0.2rem 0.5rem;
  border-radius: 3px;
  margin-bottom: var(--space-xs);
}

.card-tag.myth {
  background-color: #FEE2E2;
  color: #991B1B;
}

.card-tag.fact {
  background-color: #DCFCE7;
  color: #166534;
}

.card-tag.caution {
  background-color: #FEF3C7;
  color: #92400E;
}

/* Article Reference Layout (article-reference) */
article {
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: var(--space-2xl) var(--space-xl);
  margin-bottom: var(--space-2xl);
  max-width: var(--content-max-width);
}

.article-content {
  max-width: 75ch; /* Optimum 65-75 chars */
  margin: 0 auto 0 0;
}

.article-toc {
  background-color: var(--muted-bg);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: var(--space-md) var(--space-lg);
  margin-bottom: var(--space-xl);
}

.article-toc h3 {
  font-size: 1rem;
  margin-bottom: var(--space-xs);
}

.article-toc ul {
  list-style: none;
  padding-left: 0;
  margin: 0;
}

.article-toc li {
  margin-bottom: 0.35rem;
}

.article-toc a {
  font-size: 0.875rem;
  text-decoration: none;
  color: var(--primary-text);
}

.article-toc a:hover {
  color: var(--accent);
  text-decoration: underline;
}

.pull-quote {
  border-left: 3px solid var(--accent);
  padding: var(--space-md) var(--space-lg);
  margin: var(--space-xl) 0;
  background-color: var(--muted-bg);
  font-size: 1.1rem;
  font-style: italic;
  color: var(--primary-text);
}

.inset-box {
  border: 1px solid var(--border);
  background-color: #F8FAFA;
  padding: var(--space-lg);
  margin: var(--space-xl) 0;
  border-radius: 4px;
}

/* FAQ Details/Summary Component */
details.faq-item {
  border: 1px solid var(--border);
  border-radius: 4px;
  margin-bottom: var(--space-sm);
  background-color: var(--surface);
  transition: background-color 0.15s ease;
}

details.faq-item[open] {
  background-color: #FAFCFC;
}

summary.faq-question {
  padding: var(--space-md) var(--space-lg);
  font-weight: 600;
  font-size: 1rem;
  color: var(--primary-text);
  cursor: pointer;
  list-style: none;
  display: flex;
  justify-content: space-between;
  align-items: center;
  user-select: none;
}

summary.faq-question::-webkit-details-marker {
  display: none;
}

summary.faq-question::after {
  content: '+';
  font-size: 1.25rem;
  font-weight: 400;
  color: var(--secondary-text);
  transition: transform 0.2s ease;
}

details.faq-item[open] summary.faq-question::after {
  content: '−';
}

.faq-answer {
  padding: 0 var(--space-lg) var(--space-md) var(--space-lg);
  border-top: 1px solid var(--border);
  margin-top: var(--space-xs);
  padding-top: var(--space-md);
  color: var(--primary-text);
}

/* CTA System: Cta Inline Soft */
.cta-inline-soft {
  background-color: var(--muted-bg);
  border: 1px solid var(--border);
  border-left: 4px solid var(--accent);
  padding: var(--space-xl);
  border-radius: 4px;
  margin: var(--space-xl) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

@media (min-width: 768px) {
  .cta-inline-soft {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
}

.btn-soft {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.4rem;
  background-color: var(--accent);
  color: #FFFFFF !important;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.875rem;
  border-radius: 4px;
  border: 1px solid var(--accent);
  min-height: 44px;
  cursor: pointer;
  transition: background-color 0.15s ease;
}

.btn-soft:hover {
  background-color: var(--interactive-hover);
  border-color: var(--interactive-hover);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.65rem 1.25rem;
  background-color: var(--surface);
  color: var(--primary-text) !important;
  text-decoration: none;
  font-weight: 500;
  font-size: 0.875rem;
  border-radius: 4px;
  border: 1px solid var(--border);
  min-height: 44px;
  cursor: pointer;
}

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

/* Interactive Checklist Styles */
.checklist-container {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  margin-bottom: var(--space-xl);
}

.checklist-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  padding: var(--space-md);
  background-color: var(--surface);
  border: 1px solid var(--border);
  border-radius: 4px;
}

.checklist-item input[type="checkbox"] {
  width: 22px;
  height: 22px;
  margin-top: 3px;
  accent-color: var(--accent);
  cursor: pointer;
}

.checklist-content {
  flex: 1;
}

.checklist-content label {
  font-weight: 600;
  font-size: 1rem;
  color: var(--primary-text);
  cursor: pointer;
  display: block;
  margin-bottom: 0.25rem;
}

.checklist-score-box {
  background-color: var(--surface);
  border: 2px solid var(--accent);
  border-radius: 4px;
  padding: var(--space-lg);
  margin-top: var(--space-xl);
}

/* Tables for Comparisons and References */
.table-responsive-wrapper {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: var(--space-lg) 0;
  border: 1px solid var(--border);
  border-radius: 4px;
}

table {
  width: 100%;
  border-collapse: collapse;
  background-color: var(--surface);
  text-align: left;
  font-size: 0.875rem;
}

th, td {
  padding: var(--space-sm) var(--space-md);
  border-bottom: 1px solid var(--border);
}

th {
  background-color: var(--muted-bg);
  color: var(--primary-text);
  font-weight: 600;
}

tr:last-child td {
  border-bottom: none;
}

/* Forms */
.form-group {
  margin-bottom: var(--space-lg);
}

.form-group label {
  display: block;
  font-size: 0.875rem;
  font-weight: 600;
  margin-bottom: var(--space-xs);
  color: var(--primary-text);
}

.form-group input,
.form-group textarea,
.form-group select {
  width: 100%;
  padding: 0.65rem var(--space-md);
  border: 1px solid var(--border);
  border-radius: 4px;
  font-family: inherit;
  font-size: 0.9375rem;
  color: var(--primary-text);
  background-color: var(--surface);
}

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

.form-group input:focus,
.form-group textarea:focus,
.form-group select:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--interactive-focus-ring);
}

.form-feedback {
  padding: var(--space-md);
  border-radius: 4px;
  margin-top: var(--space-md);
  display: none;
}

.form-feedback.success {
  display: block;
  background-color: #DCFCE7;
  color: #166534;
  border: 1px solid #86EFAC;
}

/* Footer: Footer Navigation Heavy */
footer {
  margin-top: var(--space-3xl);
}

.footer-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-2xl);
  max-width: var(--content-max-width);
}

@media (min-width: 640px) {
  .footer-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 1024px) {
  .footer-grid {
    grid-template-columns: 2fr 1fr 1fr 1fr;
  }
}

.footer-col h4 {
  color: #FFFFFF;
  font-size: 0.875rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin-bottom: var(--space-md);
}

.footer-col p {
  color: #A3BFBF;
  font-size: 0.8125rem;
  line-height: 1.5;
}

.footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
}

.footer-col li {
  margin-bottom: 0.5rem;
}

.footer-col a {
  color: #D1E0E0;
  text-decoration: none;
  font-size: 0.8125rem;
}

.footer-col a:hover {
  color: #FFFFFF;
  text-decoration: underline;
}

.footer-bottom {
  border-top: 1px solid #1F4242;
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
  color: #8CA3A3;
  font-size: 0.75rem;
  max-width: var(--content-max-width);
}

@media (min-width: 768px) {
  .footer-bottom {
    flex-direction: row;
    justify-content: space-between;
    align-items: center;
  }
}

/* Pure SVG diagram & schematic styling */
.svg-diagram-card {
  background-color: #FFFFFF;
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: var(--space-lg);
  margin: var(--space-xl) 0;
}

.svg-diagram-card svg {
  width: 100%;
  height: auto;
  display: block;
}

/* Accessibility reduced motion */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}