/* ==========================================================================
   GHK-Cu Field Guide — css/style.css
   Aesthetic: flat-design-educacional-vibrante
   NO inline styles, NO gradients, NO shadows deeper than 2px
   ========================================================================== */

/* --------------------------------------------------------------------------
   1. CSS Custom Properties
   -------------------------------------------------------------------------- */
:root {
  /* Brand palette */
  --primary:            #1463E6;
  --primary-50:         #E8F0FE;
  --primary-100:        #C6DBFC;
  --primary-300:        #6FA4F2;
  --primary-700:        #0B43A6;
  --primary-900:        #072A6B;

  --secondary:          #E8722B;
  --secondary-50:       #FDEEE2;
  --secondary-300:      #F2A871;
  --secondary-700:      #B5520F;

  --accent:             #15B6A6;
  --accent-50:          #E2F7F4;
  --accent-300:         #6DD7CB;
  --accent-700:         #0E7C71;

  --copper-violet:      #5B49C9;

  /* Category hues */
  --cat-skin:           #15B6A6;
  --cat-skin-tint:      #E2F7F4;
  --cat-hair:           #F2B807;
  --cat-hair-tint:      #FDF3CF;
  --cat-mechanism:      #1463E6;
  --cat-mechanism-tint: #E8F0FE;
  --cat-chemistry:      #E8722B;
  --cat-chemistry-tint: #FDEEE2;
  --cat-safety:         #D63384;
  --cat-safety-tint:    #FBE3EF;
  --cat-reference:      #2FA94B;
  --cat-reference-tint: #E4F6E8;

  /* Neutrals */
  --neutral-0:          #FFFFFF;
  --neutral-50:         #F4F8FC;
  --neutral-100:        #E8EEF5;
  --neutral-200:        #D5DEE9;
  --neutral-400:        #9AA8B8;
  --neutral-500:        #6B7A8C;
  --neutral-700:        #3C4856;
  --neutral-900:        #1A2330;

  /* Semantic */
  --bg:                 #FCFEFF;
  --bg-alt:             #F4F8FC;
  --surface:            #FFFFFF;
  --text:               #1A2330;
  --text-muted:         #52617A;
  --text-on-color:      #FFFFFF;

  /* Typography */
  --font-heading:       'Baloo 2', 'Quicksand', 'Trebuchet MS', system-ui, sans-serif;
  --font-body:          'Mulish', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --font-mono:          'Space Mono', 'JetBrains Mono', 'Courier New', monospace;

  /* Type scale */
  --text-h1:            clamp(2.125rem, 4.75vw, 3.5rem);
  --text-h2:            clamp(1.625rem, 3.25vw, 2.375rem);
  --text-h3:            1.375rem;
  --text-h4:            1.0625rem;
  --text-body:          1.0625rem;
  --text-lede:          1.1875rem;
  --text-small:         0.875rem;
  --text-eyebrow:       0.8125rem;

  /* Layout */
  --max-width:          72rem;
  --article-max-width:  44rem;
  --container-px:       clamp(1.25rem, 3.5vw, 2.5rem);

  /* Radii */
  --radius-pill:        9999px;
  --radius-card:        18px;
  --radius-callout:     16px;
  --radius-button:      14px;
  --radius-chip:        8px;
  --radius-table:       16px;

  /* Borders */
  --border-block:       2px solid var(--neutral-200);
  --border-header:      2px solid var(--neutral-200);

  /* Transitions */
  --transition-fast:    160ms ease-out;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}

body {
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--text-body);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

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

a {
  color: var(--primary);
  text-decoration: underline;
  text-underline-offset: 2px;
}

a:hover { color: var(--primary-700); }
a:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
  border-radius: 4px;
}

ul, ol { list-style: none; }

/* --------------------------------------------------------------------------
   3. Typography
   -------------------------------------------------------------------------- */
h1, h2, h3, h4 {
  font-family: var(--font-heading);
  line-height: 1.14;
  color: var(--text);
}

h1 {
  font-size: var(--text-h1);
  font-weight: 700;
  letter-spacing: -0.01em;
  line-height: 1.1;
}

h2 {
  font-size: var(--text-h2);
  font-weight: 700;
  letter-spacing: -0.005em;
}

h3 {
  font-size: var(--text-h3);
  font-weight: 600;
}

h4 {
  font-size: var(--text-h4);
  font-weight: 600;
  font-family: var(--font-body);
}

p { margin-bottom: 1rem; }
p:last-child { margin-bottom: 0; }

strong { font-weight: 700; }
em { font-style: italic; }

.lede {
  font-size: var(--text-lede);
  line-height: 1.45;
  letter-spacing: -0.003em;
  color: var(--text-muted);
}

.eyebrow {
  font-family: var(--font-body);
  font-size: var(--text-eyebrow);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
}

code, .mono {
  font-family: var(--font-mono);
  font-size: 0.9375em;
}

/* Inline code chip */
.chip-mono {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  display: inline-flex;
  align-items: center;
  padding: 1px 6px;
  border-radius: var(--radius-chip);
  background: var(--primary-50);
  border: 2px solid var(--primary);
  color: var(--text);
  white-space: nowrap;
}

/* Category-colored chip variants */
.chip-skin    { background: var(--cat-skin-tint);      border-color: var(--cat-skin); }
.chip-hair    { background: var(--cat-hair-tint);      border-color: var(--cat-hair); }
.chip-chem    { background: var(--cat-chemistry-tint); border-color: var(--cat-chemistry); }
.chip-safety  { background: var(--cat-safety-tint);    border-color: var(--cat-safety); }
.chip-ref     { background: var(--cat-reference-tint); border-color: var(--cat-reference); }
.chip-mech    { background: var(--cat-mechanism-tint); border-color: var(--cat-mechanism); }

/* Citation superscript */
sup a.citation-link {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 700;
  min-width: 1.25rem;
  height: 1.25rem;
  padding: 0 3px;
  border-radius: 4px;
  background: var(--primary-50);
  border: 2px solid var(--primary);
  color: var(--text);
  text-decoration: none;
  vertical-align: super;
  line-height: 1;
  transition: background var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}

sup a.citation-link:hover {
  background: var(--primary);
  color: var(--text-on-color);
  transform: scale(1.06);
}

/* Page-category citation color overrides */
.page-skin    sup a.citation-link { background: var(--cat-skin-tint);      border-color: var(--cat-skin); }
.page-skin    sup a.citation-link:hover { background: var(--cat-skin); }
.page-hair    sup a.citation-link { background: var(--cat-hair-tint);      border-color: var(--cat-hair); }
.page-hair    sup a.citation-link:hover { background: var(--cat-hair); }
.page-chem    sup a.citation-link { background: var(--cat-chemistry-tint); border-color: var(--cat-chemistry); }
.page-chem    sup a.citation-link:hover { background: var(--cat-chemistry); }
.page-safety  sup a.citation-link { background: var(--cat-safety-tint);    border-color: var(--cat-safety); }
.page-safety  sup a.citation-link:hover { background: var(--cat-safety); }
.page-ref     sup a.citation-link { background: var(--cat-reference-tint); border-color: var(--cat-reference); }
.page-ref     sup a.citation-link:hover { background: var(--cat-reference); }

/* --------------------------------------------------------------------------
   4. Layout — Container & Grid
   -------------------------------------------------------------------------- */
.container {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--container-px);
}

.article-body {
  max-width: var(--article-max-width);
  margin-inline: auto;
}

.section-band {
  padding-block: 4rem;
}

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

/* Category tint bands */
.section-band--skin    { background-color: var(--cat-skin-tint); }
.section-band--hair    { background-color: var(--cat-hair-tint); }
.section-band--mech    { background-color: var(--cat-mechanism-tint); }
.section-band--chem    { background-color: var(--cat-chemistry-tint); }
.section-band--safety  { background-color: var(--cat-safety-tint); }
.section-band--ref     { background-color: var(--cat-reference-tint); }

/* --------------------------------------------------------------------------
   5. Header & Navigation
   -------------------------------------------------------------------------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--surface);
  border-bottom: var(--border-header);
  height: 4rem;
  display: flex;
  align-items: center;
}

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

.site-brand {
  font-family: var(--font-heading);
  font-size: 1.125rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  flex-shrink: 0;
}

.site-brand:hover { color: var(--primary-700); }

.brand-mark {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  position: relative;
}

.brand-mark::before {
  content: '';
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  position: absolute;
  top: 3px;
  right: 4px;
}

.brand-mark::after {
  content: '';
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--accent);
  position: absolute;
  bottom: 4px;
  left: 4px;
}

/* Desktop nav */
.site-nav { display: none; }

@media (min-width: 960px) {
  .site-nav {
    display: flex;
    align-items: center;
    gap: 0;
  }
}

.site-nav ul {
  display: flex;
  align-items: center;
  gap: 0.125rem;
}

.site-nav a {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--neutral-700);
  text-decoration: none;
  padding: 0.375rem 0.625rem;
  border-radius: 6px;
  letter-spacing: 0.06em;
  transition: color var(--transition-fast);
}

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

.nav-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--nav-cat-color, var(--primary));
  flex-shrink: 0;
  transition: width var(--transition-fast), height var(--transition-fast);
}

.site-nav a:hover .nav-dot,
.site-nav a.active .nav-dot {
  width: 8px;
  height: 8px;
}

.site-nav a.active .nav-dot {
  border-radius: 2px;
}

/* Category nav colors */
.nav-skin    { --nav-cat-color: var(--cat-skin); }
.nav-hair    { --nav-cat-color: var(--cat-hair); }
.nav-mech    { --nav-cat-color: var(--cat-mechanism); }
.nav-chem    { --nav-cat-color: var(--cat-chemistry); }
.nav-safety  { --nav-cat-color: var(--cat-safety); }
.nav-ref     { --nav-cat-color: var(--cat-reference); }

/* Hamburger button */
.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 2.5rem;
  height: 2.5rem;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
  border-radius: 6px;
}

.nav-toggle:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

.nav-toggle span {
  display: block;
  width: 100%;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

@media (min-width: 960px) {
  .nav-toggle { display: none; }
}

/* Mobile nav panel */
.mobile-nav {
  display: none;
  position: fixed;
  inset: 0;
  z-index: 200;
  background: var(--surface);
  padding: 1.5rem var(--container-px);
  flex-direction: column;
  overflow-y: auto;
}

.mobile-nav.is-open { display: flex; }

.mobile-nav-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 2rem;
}

.mobile-nav-close {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 1.5rem;
  color: var(--text);
  padding: 0.25rem;
  line-height: 1;
}

.mobile-nav ul { gap: 0.5rem; display: flex; flex-direction: column; }

.mobile-nav a {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1rem 1.25rem;
  border-radius: 12px;
  background: var(--mobile-cat-tint, var(--primary-50));
  color: var(--text);
  text-decoration: none;
  font-weight: 600;
  font-size: 1rem;
  transition: background var(--transition-fast);
}

.mobile-nav a:hover { opacity: 0.85; }

.mobile-nav .nav-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  background: var(--mobile-cat-color, var(--primary));
  flex-shrink: 0;
}

.mobile-nav .nav-skin-item    { --mobile-cat-tint: var(--cat-skin-tint);      --mobile-cat-color: var(--cat-skin); }
.mobile-nav .nav-hair-item    { --mobile-cat-tint: var(--cat-hair-tint);      --mobile-cat-color: var(--cat-hair); }
.mobile-nav .nav-mech-item    { --mobile-cat-tint: var(--cat-mechanism-tint); --mobile-cat-color: var(--cat-mechanism); }
.mobile-nav .nav-chem-item    { --mobile-cat-tint: var(--cat-chemistry-tint); --mobile-cat-color: var(--cat-chemistry); }
.mobile-nav .nav-safety-item  { --mobile-cat-tint: var(--cat-safety-tint);    --mobile-cat-color: var(--cat-safety); }
.mobile-nav .nav-ref-item     { --mobile-cat-tint: var(--cat-reference-tint); --mobile-cat-color: var(--cat-reference); }

/* --------------------------------------------------------------------------
   6. Hero — Index (two-block flat split)
   -------------------------------------------------------------------------- */
.hero-index {
  background: var(--primary-50);
}

.hero-index .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
  padding-block: 3rem;
}

@media (min-width: 960px) {
  .hero-index .container {
    grid-template-columns: 7fr 5fr;
    align-items: center;
    padding-block: 4.5rem;
  }
}

.hero-content { max-width: 42rem; }

.hero-eyebrow-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background: var(--secondary);
  color: var(--text-on-color);
  border-radius: var(--radius-pill);
  padding: 0.375rem 0.875rem;
  margin-bottom: 1.25rem;
}

.hero-eyebrow-chip .eyebrow { color: var(--text-on-color); }

.hero-atom-glyph {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--text-on-color);
  opacity: 0.85;
  flex-shrink: 0;
}

.hero-h1 { margin-bottom: 1rem; }

.hero-lede {
  margin-bottom: 1.75rem;
}

.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-bottom: 2rem;
}

/* Chapter chips row */
.chapter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

/* Hero illustration block */
.hero-illustration {
  background: var(--primary);
  border-radius: 24px;
  border: 2px solid var(--primary-700);
  padding: 1.5rem;
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 280px;
  position: relative;
  overflow: hidden;
}

.hero-illustration img {
  width: 100%;
  height: auto;
  border-radius: 18px;
  border: 2px solid var(--text-on-color);
}

/* Confetti dots (decorative, CSS-only) */
.hero-illustration::before {
  content: '';
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--cat-hair);
}

.hero-illustration::after {
  content: '';
  position: absolute;
  bottom: 1.25rem;
  left: 1.25rem;
  width: 10px;
  height: 10px;
  background: var(--accent);
  border-radius: 3px;
  transform: rotate(15deg);
}

/* --------------------------------------------------------------------------
   7. Hero — Inner pages (single band)
   -------------------------------------------------------------------------- */
.hero-inner {
  padding-block: 3rem 2.5rem;
}

.hero-inner .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

@media (min-width: 768px) {
  .hero-inner .container {
    grid-template-columns: 1fr auto;
    align-items: center;
  }
}

.hero-inner-content { max-width: 42rem; }

.hero-inner h1 {
  font-size: clamp(1.75rem, 3.5vw, 2.75rem);
  margin-bottom: 0.75rem;
}

.hero-inner .lede { margin-bottom: 1.5rem; }

/* Category-colored hero chip */
.chapter-label-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  border-radius: var(--radius-chip);
  padding: 0.25rem 0.75rem;
  border: 2px solid;
  font-family: var(--font-body);
  font-size: var(--text-eyebrow);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-bottom: 1rem;
  color: var(--text);
}

/* Chapter colors */
.label-skin    { background: var(--cat-skin-tint);      border-color: var(--cat-skin);      color: var(--accent-700); }
.label-hair    { background: var(--cat-hair-tint);      border-color: var(--cat-hair);      color: #96720A; }
.label-mech    { background: var(--cat-mechanism-tint); border-color: var(--cat-mechanism); color: var(--primary-700); }
.label-chem    { background: var(--cat-chemistry-tint); border-color: var(--cat-chemistry); color: var(--secondary-700); }
.label-safety  { background: var(--cat-safety-tint);    border-color: var(--cat-safety);    color: #8F1551; }
.label-ref     { background: var(--cat-reference-tint); border-color: var(--cat-reference); color: #1A6B2E; }

/* --------------------------------------------------------------------------
   8. Buttons
   -------------------------------------------------------------------------- */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  font-family: var(--font-heading);
  font-size: 0.9375rem;
  font-weight: 600;
  text-decoration: none;
  padding: 0.875rem 1.75rem;
  border-radius: var(--radius-button);
  border: 2px solid;
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
  white-space: nowrap;
}

.btn:focus-visible {
  outline: 3px solid var(--primary);
  outline-offset: 2px;
}

.btn-arrow { transition: transform var(--transition-fast); }

.btn:hover .btn-arrow { transform: translateX(3px); }

@media (prefers-reduced-motion: reduce) {
  .btn:hover .btn-arrow { transform: none; }
}

/* Primary */
.btn-primary {
  background: var(--primary);
  color: var(--text-on-color);
  border-color: var(--primary);
}

.btn-primary:hover {
  background: #2E78F0;
  border-color: #2E78F0;
  transform: scale(1.02);
  color: var(--text-on-color);
}

@media (prefers-reduced-motion: reduce) {
  .btn-primary:hover { transform: none; }
}

/* Secondary */
.btn-secondary {
  background: var(--surface);
  color: var(--primary);
  border-color: var(--primary);
}

.btn-secondary:hover {
  background: var(--primary-50);
  transform: scale(1.02);
}

@media (prefers-reduced-motion: reduce) {
  .btn-secondary:hover { transform: none; }
}

/* Category variants */
.btn-skin    { background: var(--cat-skin);      border-color: var(--cat-skin);      color: var(--text); }
.btn-skin:hover { background: var(--accent-700); border-color: var(--accent-700); color: var(--text-on-color); }
.btn-hair    { background: var(--cat-hair);      border-color: var(--cat-hair);      color: var(--text); }
.btn-hair:hover { opacity: 0.88; }
.btn-chem    { background: var(--cat-chemistry); border-color: var(--cat-chemistry); color: var(--text-on-color); }
.btn-chem:hover { background: var(--secondary-700); border-color: var(--secondary-700); }
.btn-safety  { background: var(--cat-safety);    border-color: var(--cat-safety);    color: var(--text-on-color); }
.btn-ref     { background: var(--cat-reference); border-color: var(--cat-reference); color: var(--text); }

/* --------------------------------------------------------------------------
   9. Chapter Chip (nav pill)
   -------------------------------------------------------------------------- */
.chip {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  font-family: var(--font-heading);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text);
  text-decoration: none;
  padding: 0.375rem 0.875rem;
  border-radius: var(--radius-pill);
  border: 2px solid;
  transition: background var(--transition-fast), color var(--transition-fast), transform var(--transition-fast);
}

.chip:hover { transform: scale(1.04); }

@media (prefers-reduced-motion: reduce) {
  .chip:hover { transform: none; }
}

.chip-icon {
  width: 14px;
  height: 14px;
  border-radius: 3px;
  flex-shrink: 0;
}

/* Chip category variants */
.chip-cat-skin    { background: var(--cat-skin-tint);      border-color: var(--cat-skin); }
.chip-cat-skin.active    { background: var(--cat-skin);    color: var(--text-on-color); }
.chip-cat-hair    { background: var(--cat-hair-tint);      border-color: var(--cat-hair); }
.chip-cat-hair.active    { background: var(--cat-hair);    color: var(--text); }
.chip-cat-mech    { background: var(--cat-mechanism-tint); border-color: var(--cat-mechanism); }
.chip-cat-mech.active    { background: var(--cat-mechanism); color: var(--text-on-color); }
.chip-cat-chem    { background: var(--cat-chemistry-tint); border-color: var(--cat-chemistry); }
.chip-cat-chem.active    { background: var(--cat-chemistry); color: var(--text-on-color); }
.chip-cat-safety  { background: var(--cat-safety-tint);    border-color: var(--cat-safety); }
.chip-cat-safety.active  { background: var(--cat-safety);  color: var(--text-on-color); }
.chip-cat-ref     { background: var(--cat-reference-tint); border-color: var(--cat-reference); }
.chip-cat-ref.active     { background: var(--cat-reference); color: var(--text); }

/* --------------------------------------------------------------------------
   10. Section Headers with Chapter Number Block
   -------------------------------------------------------------------------- */
.section-heading-wrap {
  display: flex;
  align-items: flex-start;
  gap: 0.875rem;
  margin-bottom: 1.5rem;
}

.chapter-numeral {
  font-family: var(--font-mono);
  font-size: 0.9375rem;
  font-weight: 700;
  color: var(--text-on-color);
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  margin-top: 0.25rem;
}

.chapter-numeral--skin    { background: var(--cat-skin); }
.chapter-numeral--hair    { background: var(--cat-hair);    color: var(--text); }
.chapter-numeral--mech    { background: var(--cat-mechanism); }
.chapter-numeral--chem    { background: var(--cat-chemistry); }
.chapter-numeral--safety  { background: var(--cat-safety); }
.chapter-numeral--ref     { background: var(--cat-reference); color: var(--text); }
.chapter-numeral--default { background: var(--neutral-700); }

.section-heading-content { flex: 1; }

.section-heading-content h2 { margin-bottom: 0.5rem; }

.section-rule {
  height: 3px;
  border-radius: 2px;
  width: 66%;
  margin-top: 0.375rem;
}

.rule-skin    { background: var(--cat-skin); }
.rule-hair    { background: var(--cat-hair); }
.rule-mech    { background: var(--cat-mechanism); }
.rule-chem    { background: var(--cat-chemistry); }
.rule-safety  { background: var(--cat-safety); }
.rule-ref     { background: var(--cat-reference); }
.rule-default { background: var(--neutral-400); }

/* Subsection eyebrow (H3 level) */
.subsection-eyebrow {
  font-family: var(--font-body);
  font-size: var(--text-eyebrow);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 0.375rem;
}

.eyebrow-skin    { color: var(--cat-skin); }
.eyebrow-hair    { color: #96720A; }
.eyebrow-mech    { color: var(--primary-700); }
.eyebrow-chem    { color: var(--secondary-700); }
.eyebrow-safety  { color: #8F1551; }
.eyebrow-ref     { color: #1A6B2E; }

/* --------------------------------------------------------------------------
   11. Cards
   -------------------------------------------------------------------------- */
.card {
  background: var(--surface);
  border: 2px solid var(--neutral-200);
  border-radius: var(--radius-card);
  padding: 1.75rem 1.75rem 1.75rem 2rem;
  position: relative;
  transition: transform var(--transition-fast);
}

.card::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 6px;
  border-radius: var(--radius-card) 0 0 var(--radius-card);
  background: var(--card-cat-color, var(--primary));
  transition: width var(--transition-fast);
}

.card:hover { transform: translateY(-2px); }
.card:hover::before { width: 8px; }

@media (prefers-reduced-motion: reduce) {
  .card:hover { transform: none; }
}

/* Category card bar colors */
.card-skin    { --card-cat-color: var(--cat-skin); }
.card-hair    { --card-cat-color: var(--cat-hair); }
.card-mech    { --card-cat-color: var(--cat-mechanism); }
.card-chem    { --card-cat-color: var(--cat-chemistry); }
.card-safety  { --card-cat-color: var(--cat-safety); }
.card-ref     { --card-cat-color: var(--cat-reference); }

.card-header {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  margin-bottom: 0.875rem;
}

.card-icon-tile {
  width: 36px;
  height: 36px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1rem;
}

.card-icon-tile--skin    { background: var(--cat-skin);      color: var(--text); }
.card-icon-tile--hair    { background: var(--cat-hair);      color: var(--text); }
.card-icon-tile--mech    { background: var(--cat-mechanism); color: var(--text-on-color); }
.card-icon-tile--chem    { background: var(--cat-chemistry); color: var(--text-on-color); }
.card-icon-tile--safety  { background: var(--cat-safety);    color: var(--text-on-color); }
.card-icon-tile--ref     { background: var(--cat-reference); color: var(--text); }

.card h3 { font-size: 1.25rem; margin-bottom: 0.5rem; }

/* Card grid */
.cards-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

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

@media (min-width: 1024px) {
  .cards-grid { grid-template-columns: repeat(3, 1fr); }
}

/* --------------------------------------------------------------------------
   12. Callouts
   -------------------------------------------------------------------------- */
.callout {
  display: flex;
  gap: 1rem;
  padding: 1.5rem;
  border-radius: var(--radius-callout);
  border: 2px solid;
  margin-block: 1.5rem;
}

.callout-icon {
  width: 32px;
  height: 32px;
  border-radius: 8px;
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.callout-body { flex: 1; }

.callout-eyebrow {
  font-family: var(--font-body);
  font-size: var(--text-eyebrow);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 0.5rem;
}

/* Callout variants */
.callout--finding {
  background: var(--cat-skin-tint);
  border-color: var(--cat-skin);
}
.callout--finding .callout-eyebrow { color: var(--accent-700); }
.callout--finding .callout-icon { background: var(--cat-skin); color: var(--text); }

.callout--note {
  background: var(--cat-chemistry-tint);
  border-color: var(--cat-chemistry);
}
.callout--note .callout-eyebrow { color: var(--secondary-700); }
.callout--note .callout-icon { background: var(--cat-chemistry); color: var(--text-on-color); }

.callout--safety {
  background: var(--cat-safety-tint);
  border-color: var(--cat-safety);
}
.callout--safety .callout-eyebrow { color: #8F1551; }
.callout--safety .callout-icon { background: var(--cat-safety); color: var(--text-on-color); }

.callout--definition {
  background: var(--cat-mechanism-tint);
  border-color: var(--cat-mechanism);
}
.callout--definition .callout-eyebrow { color: var(--primary-700); }
.callout--definition .callout-icon { background: var(--cat-mechanism); color: var(--text-on-color); }

/* --------------------------------------------------------------------------
   13. Stat Blocks
   -------------------------------------------------------------------------- */
.stat-blocks {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
  margin-block: 2rem;
}

@media (min-width: 640px) {
  .stat-blocks { grid-template-columns: repeat(4, 1fr); }
}

.stat-block {
  padding: 1.25rem 1rem;
  border-radius: var(--radius-callout);
  text-align: center;
  position: relative;
}

.stat-block--skin    { background: var(--cat-skin);      color: var(--text); }
.stat-block--hair    { background: var(--cat-hair);      color: var(--text); }
.stat-block--mech    { background: var(--cat-mechanism); color: var(--text-on-color); }
.stat-block--chem    { background: var(--cat-chemistry); color: var(--text-on-color); }
.stat-block--safety  { background: var(--cat-safety);    color: var(--text-on-color); }
.stat-block--ref     { background: var(--cat-reference); color: var(--text); }

.stat-value {
  font-family: var(--font-heading);
  font-size: clamp(1.75rem, 3.5vw, 2.75rem);
  font-weight: 800;
  letter-spacing: -0.01em;
  display: block;
  line-height: 1.1;
}

.stat-label {
  font-family: var(--font-body);
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  display: block;
  margin-top: 0.25rem;
}

/* --------------------------------------------------------------------------
   14. Figure / Image blocks
   -------------------------------------------------------------------------- */
.figure-block {
  border: 2px solid var(--neutral-200);
  border-radius: var(--radius-card);
  overflow: hidden;
  position: relative;
  margin-block: 2rem;
}

.figure-block::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 6px;
  background: var(--fig-cat-color, var(--primary));
}

.figure-block--skin    { --fig-cat-color: var(--cat-skin); }
.figure-block--hair    { --fig-cat-color: var(--cat-hair); }
.figure-block--mech    { --fig-cat-color: var(--cat-mechanism); }
.figure-block--chem    { --fig-cat-color: var(--cat-chemistry); }
.figure-block--skin    { --fig-cat-color: var(--cat-skin); }

.figure-block img {
  width: 100%;
  height: auto;
  display: block;
}

.figure-caption {
  padding: 0.875rem 1.25rem;
  background: var(--surface);
}

.figure-caption .eyebrow { margin-bottom: 0.25rem; }
.figure-caption p { font-style: italic; font-size: var(--text-small); color: var(--text-muted); margin: 0; }

/* --------------------------------------------------------------------------
   15. Tables
   -------------------------------------------------------------------------- */
.table-wrap {
  border: 2px solid var(--neutral-200);
  border-radius: var(--radius-table);
  overflow: hidden;
  margin-block: 1.5rem;
  overflow-x: auto;
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 32rem;
}

thead tr {
  background: var(--table-cat-color, var(--primary));
}

.table-skin    { --table-cat-color: var(--cat-skin); }
.table-hair    { --table-cat-color: var(--cat-hair); }
.table-mech    { --table-cat-color: var(--cat-mechanism); }
.table-chem    { --table-cat-color: var(--cat-chemistry); }

thead th {
  padding: 0.875rem 1rem;
  font-family: var(--font-heading);
  font-size: 0.8125rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-on-color);
  text-align: left;
}

.table-skin thead th,
.table-hair thead th,
.table-ref thead th {
  color: var(--text);
}

tbody tr + tr {
  border-top: 2px solid var(--neutral-100);
}

tbody tr:hover { background: var(--bg-alt); }

td {
  padding: 0.875rem 1rem;
  font-size: var(--text-small);
  vertical-align: top;
}

td:first-child {
  padding-left: 1.25rem;
  position: relative;
}

td:first-child::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--table-cat-color, var(--primary));
}

.td-mono { font-family: var(--font-mono); }

/* --------------------------------------------------------------------------
   16. Accordion (FAQ)
   -------------------------------------------------------------------------- */
.accordion-list {
  display: flex;
  flex-direction: column;
  gap: 0.75rem;
}

.accordion-item {
  background: var(--surface);
  border: 2px solid var(--neutral-200);
  border-radius: var(--radius-callout);
  overflow: hidden;
  position: relative;
}

.accordion-item::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 6px;
  background: var(--cat-safety);
}

.accordion-trigger {
  width: 100%;
  background: none;
  border: none;
  padding: 1.25rem 1.25rem 1.25rem 1.75rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  cursor: pointer;
  text-align: left;
  font-family: var(--font-heading);
  font-size: var(--text-h4);
  font-weight: 600;
  color: var(--text);
  transition: background var(--transition-fast);
}

.accordion-trigger:hover { background: var(--cat-safety-tint); }

.accordion-trigger:focus-visible {
  outline: 3px solid var(--cat-safety);
  outline-offset: -3px;
}

.accordion-icon {
  width: 24px;
  height: 24px;
  border-radius: 6px;
  background: var(--cat-safety);
  color: var(--text-on-color);
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1;
  transition: transform var(--transition-fast);
}

@media (prefers-reduced-motion: reduce) {
  .accordion-icon { transition: none; }
}

.accordion-item.is-open .accordion-icon {
  transform: rotate(45deg);
}

.accordion-body {
  display: none;
  padding: 0 1.25rem 1.25rem 1.75rem;
  background: var(--cat-safety-tint);
}

.accordion-item.is-open .accordion-body { display: block; }

/* --------------------------------------------------------------------------
   17. References List
   -------------------------------------------------------------------------- */
.references-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.references-list li {
  padding: 1.25rem 1.25rem 1.25rem 1.75rem;
  background: var(--surface);
  border: 2px solid var(--neutral-200);
  border-radius: 12px;
  position: relative;
  font-size: var(--text-small);
  line-height: 1.6;
}

.references-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 4px;
  border-radius: 12px 0 0 12px;
  background: var(--cat-reference);
}

.ref-num {
  font-family: var(--font-mono);
  font-weight: 700;
  color: var(--primary);
  margin-right: 0.5rem;
}

.ref-link {
  color: var(--primary);
  word-break: break-all;
}

/* --------------------------------------------------------------------------
   18. Content sections in article body
   -------------------------------------------------------------------------- */
.content-section {
  padding-block: 3rem;
}

.content-section + .content-section {
  border-top: 2px solid var(--neutral-100);
}

.content-section h3 {
  margin-bottom: 0.875rem;
}

.content-section p + h3 { margin-top: 1.5rem; }
.content-section p + h4 { margin-top: 1.25rem; }

.content-section h4 {
  margin-bottom: 0.5rem;
}

.content-section ul,
.content-section ol {
  margin-block: 0.75rem;
  padding-left: 1.5rem;
}

.content-section ul { list-style: disc; }
.content-section ol { list-style: decimal; }

.content-section li { margin-bottom: 0.375rem; }

/* --------------------------------------------------------------------------
   19. Contact Form
   -------------------------------------------------------------------------- */
.contact-form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  max-width: 36rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.375rem;
}

.form-label {
  font-weight: 600;
  font-size: 0.9375rem;
  color: var(--text);
}

.form-input,
.form-select,
.form-textarea {
  padding: 0.75rem 1rem;
  border: 2px solid var(--neutral-200);
  border-radius: 10px;
  font-family: var(--font-body);
  font-size: var(--text-body);
  color: var(--text);
  background: var(--surface);
  transition: border-color var(--transition-fast);
  width: 100%;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
  outline: none;
  border-color: var(--primary);
}

.form-textarea {
  min-height: 8rem;
  resize: vertical;
}

/* --------------------------------------------------------------------------
   20. Footer
   -------------------------------------------------------------------------- */
.site-footer { margin-top: auto; }

.footer-disclaimer-band {
  padding-block: 1.25rem;
  background: var(--bg);
  border-top: 2px solid var(--neutral-200);
  text-align: center;
}

.footer-disclaimer {
  font-family: var(--font-body);
  font-style: italic;
  font-size: 0.9375rem;
  color: var(--text-muted);
  max-width: 56rem;
  margin-inline: auto;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.75rem;
}

.footer-atom {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--secondary);
  flex-shrink: 0;
}

.footer-links-band {
  background: var(--primary-50);
  padding-block: 3rem;
}

.footer-columns {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

@media (min-width: 640px) {
  .footer-columns { grid-template-columns: repeat(3, 1fr); }
}

.footer-col-heading {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-heading);
  font-size: 0.9375rem;
  font-weight: 700;
  margin-bottom: 1rem;
}

.footer-col-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
}

.footer-col-heading--mech    .footer-col-dot { background: var(--cat-mechanism); }
.footer-col-heading--mech    { color: var(--primary-700); }
.footer-col-heading--skin    .footer-col-dot { background: var(--cat-skin); }
.footer-col-heading--skin    { color: var(--accent-700); }
.footer-col-heading--ref     .footer-col-dot { background: var(--cat-reference); }
.footer-col-heading--ref     { color: #1A6B2E; }

.footer-links {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.footer-links a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 500;
  font-size: 0.9375rem;
  color: var(--text);
  text-decoration: none;
}

.footer-links a::before {
  content: '';
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: var(--footer-col-dot-color, var(--primary));
  flex-shrink: 0;
  transition: width var(--transition-fast), height var(--transition-fast);
}

.footer-links a:hover::before {
  width: 6px;
  height: 6px;
}

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

.footer-col--mech .footer-links a::before { --footer-col-dot-color: var(--cat-mechanism); }
.footer-col--skin .footer-links a::before { --footer-col-dot-color: var(--cat-skin); }
.footer-col--ref  .footer-links a::before { --footer-col-dot-color: var(--cat-reference); }

.footer-bottom {
  background: var(--primary);
  padding-block: 1.25rem;
}

.footer-bottom .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.footer-bottom-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--text-on-color);
  text-decoration: none;
  font-size: 1rem;
}

.footer-copyright {
  font-size: var(--text-small);
  color: rgba(255,255,255,0.7);
}

/* --------------------------------------------------------------------------
   21. Glossary
   -------------------------------------------------------------------------- */
.glossary-list {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.glossary-term {
  padding: 1.25rem 1.25rem 1.25rem 1.75rem;
  background: var(--surface);
  border: 2px solid var(--neutral-200);
  border-radius: 12px;
  position: relative;
}

.glossary-term::before {
  content: '';
  position: absolute;
  left: 0; top: 0; bottom: 0;
  width: 4px;
  border-radius: 12px 0 0 12px;
  background: var(--cat-mechanism);
}

.glossary-term dt {
  font-family: var(--font-heading);
  font-weight: 700;
  font-size: var(--text-h4);
  margin-bottom: 0.375rem;
}

.glossary-term dd { font-size: var(--text-small); color: var(--text-muted); line-height: 1.55; }

/* --------------------------------------------------------------------------
   22. 404 page
   -------------------------------------------------------------------------- */
.page-404 {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  min-height: 60vh;
  padding: 4rem var(--container-px);
}

.page-404 .big-num {
  font-family: var(--font-heading);
  font-size: clamp(5rem, 15vw, 10rem);
  font-weight: 800;
  color: var(--primary);
  line-height: 1;
  margin-bottom: 1rem;
}

/* --------------------------------------------------------------------------
   23. Utilities
   -------------------------------------------------------------------------- */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  white-space: nowrap;
  border: 0;
}

.text-center { text-align: center; }
.mb-0 { margin-bottom: 0; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }
.mt-4 { margin-top: 2rem; }
.mt-6 { margin-top: 3rem; }

.page-main { min-height: 60vh; }

/* -------------------------------------------------------------------------
   24. Utility helpers (replaces inline styles)
   ----------------------------------------------------------------------- */
.list-disc {
  list-style: disc;
  padding-left: 1.25rem;
  margin-top: 0.5rem;
}

.cards-grid--auto {
  grid-template-columns: repeat(auto-fit, minmax(14rem, 1fr));
}

.cta-row--center {
  justify-content: center;
  margin-top: 2rem;
}

.chapter-chips--center {
  justify-content: center;
  margin-top: 2rem;
}

/* Category chip icon colors (moved out of inline style) */
.chip-icon--skin    { background: var(--cat-skin); }
.chip-icon--hair    { background: var(--cat-hair); }
.chip-icon--mech    { background: var(--cat-mechanism); }
.chip-icon--chem    { background: var(--cat-chemistry); }
.chip-icon--safety  { background: var(--cat-safety); }
.chip-icon--ref     { background: var(--cat-reference); }

/* Hero illustration category variants */
.hero-illustration--skin {
  max-width: 320px;
  background: var(--cat-skin-tint);
  border-color: var(--cat-skin);
}
.hero-illustration--hair {
  max-width: 320px;
  background: var(--cat-hair-tint);
  border-color: var(--cat-hair);
}
.hero-illustration--mech {
  max-width: 340px;
}
.hero-illustration--chem {
  max-width: 320px;
  background: var(--cat-chemistry-tint);
  border-color: var(--cat-chemistry);
}