*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
 :root {
  --black:    #afafaf;
  --dark:     #9e9e9e;
  --surface:  #bcbcbc;
  --surface2: #c8c8c8;
  --border:   #989898;
  --border2:  #888888;
  --muted:    #555555;
  --sub:      #707086;
  --text:     #1a1a1a;
  --light:    #0a0a0a;
  --white:    #0a0a0a;
  --gold:     #1a4f8a;
  --coral:    #174070;
  --blue:     #2c6bb0;
  --gold-dim: rgba(26,79,138,0.12);
  --coral-dim:rgba(23,64,112,0.10);
  --blue-dim: rgba(44,107,176,0.12);
}
 html { scroll-behavior: smooth; }
 body {
  background: var(--black);
  color: var(--text);
  font-family: 'Source Sans 3', 'Helvetica Neue', sans-serif;
  font-weight: 400;
  line-height: 1.7;
  overflow-x: hidden;
}
 /*  SCROLLBAR  */
::-webkit-scrollbar { width: 4px; }
::-webkit-scrollbar-track { background: var(--dark); }
::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 2px; }
 /*  HEADER  */
.site-header {
  position: sticky; top: 0; z-index: 100;
  background: rgba(175,175,175,0.97);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
}
.header-inner {
  max-width: 1200px; margin: 0 auto;
  padding: 0 2rem;
  height: 76px;
  display: flex; align-items: center;
  justify-content: space-between; gap: 2rem;
}
.logo {
  display: flex; align-items: center;
  text-decoration: none; flex-shrink: 0;
}
.logo-mark {
  display: block;
  shape-rendering: geometricPrecision;
  text-rendering: optimizeLegibility;
}
 .main-nav { display: flex; gap: 0.2rem; }
.main-nav a {
  font-size: 0.78rem; font-weight: 400;
  letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--muted); text-decoration: none;
  padding: 0.4rem 0.8rem; border-radius: 4px;
  transition: color 0.2s, background 0.2s;
}
.main-nav a:hover { color: var(--white); background: var(--surface); }
 /*  DROPDOWN  */
.nav-dropdown {
  position: relative;
}
.nav-dropdown-trigger {
  display: flex; align-items: center; gap: 0.3rem;
  font-size: 0.78rem; font-weight: 400;
  letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--muted); text-decoration: none;
  padding: 0.4rem 0.8rem; border-radius: 4px;
  transition: color 0.2s, background 0.2s;
  cursor: pointer; background: none; border: none;
  white-space: nowrap;
}
.nav-dropdown-trigger:hover,
.nav-dropdown:hover .nav-dropdown-trigger { color: var(--white); background: var(--surface); }
.nav-dropdown-trigger.active { color: var(--white); }
.nav-dropdown-caret {
  font-size: 0.5rem; opacity: 0.5;
  transition: transform 0.2s;
  display: inline-block;
}
.nav-dropdown:hover .nav-dropdown-caret { transform: rotate(180deg); }
 .nav-dropdown-menu {
  display: none;
  position: absolute;
  top: 100%;
  left: 0;
  padding-top: 8px;
  min-width: 200px;
  z-index: 200;
}
.nav-dropdown-menu::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 8px;
}
.nav-dropdown-menu-inner {
  background: rgba(175,175,175,0.98);
  backdrop-filter: blur(8px);
  border: 1px solid var(--border2);
  border-radius: 6px;
  overflow: hidden;
  box-shadow: 0 8px 24px rgba(0,0,0,0.15);
}
.nav-dropdown:hover .nav-dropdown-menu { display: block; }
 .nav-dropdown-menu a {
  display: block;
  font-size: 0.75rem; font-weight: 400;
  letter-spacing: 0.06em; text-transform: uppercase;
  color: var(--muted); text-decoration: none;
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--border);
  border-radius: 0;
  background: none;
  transition: color 0.15s, background 0.15s;
}
.nav-dropdown-menu a:last-child { border-bottom: none; }
.nav-dropdown-menu a:hover { color: var(--white); background: var(--surface2); }
.nav-dropdown-menu .dropdown-section-link {
  font-weight: 500; color: var(--text);
  border-bottom: 1px solid var(--border2);
}
.nav-dropdown-menu .dropdown-tool-label {
  font-size: 0.58rem; color: var(--muted);
  letter-spacing: 0.15em; padding: 0.4rem 1rem 0.2rem;
  text-transform: uppercase; display: block;
}
 .header-cta {
  font-size: 0.75rem; font-weight: 500;
  letter-spacing: 0.08em; text-transform: uppercase;
  text-decoration: none; padding: 0.5rem 1.1rem;
  border-radius: 5px;
  border: 1px solid var(--border2);
  color: var(--text); transition: all 0.2s;
}
.header-cta:hover { border-color: var(--gold); color: var(--gold); }
 /*  HERO  */
.hero {
  min-height: 85vh;
  display: flex; align-items: center;
  position: relative; overflow: hidden;
  background: var(--dark);
  border-bottom: 1px solid var(--border);
}
 /* CIE chromaticity diagram as subtle background */
.hero-bg {
  position: absolute; inset: 0; pointer-events: none;
}
.hero-bg svg { width: 100%; height: 100%; opacity: 0.04; }
 /* Spectrum gradient wash on right side */
.hero-spectrum {
  position: absolute; right: 0; top: 0; bottom: 0;
  width: 40%;
  background: linear-gradient(to left, transparent, rgba(26,79,138,0.05) 40%, transparent);
  pointer-events: none;
}
 .hero-inner {
  position: relative; z-index: 1;
  max-width: 1200px; margin: 0 auto;
  padding: 5rem 2rem;
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 5rem; align-items: center;
}
 .hero-left {}
 .hero-standard {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.68rem; color: var(--gold);
  letter-spacing: 0.2em; text-transform: uppercase;
  margin-bottom: 1.5rem;
  display: flex; align-items: center; gap: 0.75rem;
}
.hero-standard::before {
  content: '';
  display: block; width: 28px; height: 1px;
  background: var(--gold);
}
 .hero h1 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: clamp(2.8rem, 5vw, 4.4rem);
  font-weight: 400; color: var(--white);
  line-height: 1.1; letter-spacing: -0.01em;
  margin-bottom: 1.5rem;
}
.hero h1 em { font-style: italic; color: var(--light); }
 .hero-desc {
  font-size: 1rem; line-height: 1.85;
  color: var(--text); max-width: 480px;
  margin-bottom: 2.5rem;
}
 .hero-actions { display: flex; gap: 1rem; flex-wrap: wrap; }
.btn-primary {
  font-size: 0.78rem; font-weight: 500;
  letter-spacing: 0.1em; text-transform: uppercase;
  text-decoration: none; padding: 0.85rem 1.8rem;
  border-radius: 5px; background: #1a4f8a;
  color: #ffffff; transition: all 0.2s;
  display: inline-block;
}
.btn-primary:hover { background: #0f3566; transform: translateY(-1px); }
.btn-ghost {
  font-size: 0.78rem; font-weight: 400;
  letter-spacing: 0.1em; text-transform: uppercase;
  text-decoration: none; padding: 0.85rem 1.8rem;
  border-radius: 5px; border: 1px solid var(--border2);
  color: var(--text); transition: all 0.2s;
  display: inline-block;
}
.btn-ghost:hover { border-color: #1a4f8a; color: #1a4f8a; }
 /* CIE diagram illustration */
.hero-right {
  display: flex; align-items: center; justify-content: center;
}
.cie-diagram {
  position: relative; width: 100%; max-width: 420px;
}
.cie-diagram svg { width: 100%; height: auto; }
 /*  DEFINITION BAND  */
.definition-band {
  background: var(--dark);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
  padding: 2.5rem 2rem;
}
.definition-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: auto 1fr;
  gap: 3rem; align-items: center;
}
.definition-label {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 3.5rem; font-weight: 400;
  color: #888888; letter-spacing: -0.04em;
  line-height: 1; white-space: nowrap;
}
.definition-text {
  border-left: 1px solid var(--border2);
  padding-left: 3rem;
}
.definition-text h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 1.15rem; font-weight: 400;
  color: var(--white); margin-bottom: 0.5rem;
}
.definition-text p {
  font-size: 0.9rem; color: var(--text); line-height: 1.75; margin-bottom: 1rem;
}
.definition-text p:last-of-type { margin-bottom: 0; }
.definition-text .spec {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.78rem; color: var(--gold);
  margin-top: 0.75rem; display: block;
}
 /*  SECTIONS GRID  */
.sections-area {
  padding: 6rem 2rem;
  background: var(--black); /* white */
}
.sections-header {
  max-width: 1200px; margin: 0 auto 3rem;
}
.section-eyebrow {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.68rem; color: var(--muted);
  letter-spacing: 0.18em; text-transform: uppercase;
  margin-bottom: 0.75rem;
  display: flex; align-items: center; gap: 0.6rem;
}
.section-eyebrow::before {
  content: ''; display: block;
  width: 16px; height: 1px; background: var(--muted);
}
.sections-header h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: clamp(1.6rem, 2.5vw, 2.2rem);
  font-weight: 400; color: var(--white);
}
.sections-header h2 em { font-style: italic; }
 .sections-grid {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: repeat(3, 1fr);
  gap: 1px; background: var(--border);
  border: 1px solid var(--border);
  border-radius: 10px; overflow: hidden;
}
.section-card {
  background: var(--surface);
  padding: 2rem; text-decoration: none;
  transition: background 0.2s;
  display: flex; flex-direction: column;
}
.section-card:hover { background: var(--surface2); }
.section-card-num {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.65rem; color: var(--muted);
  letter-spacing: 0.12em; margin-bottom: 1.25rem;
}
.section-card-icon {
  font-size: 1.4rem; margin-bottom: 1rem;
}
.section-card h3 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 1.05rem; font-weight: 400;
  color: var(--white); line-height: 1.3;
  margin-bottom: 0.6rem;
}
.section-card p {
  font-size: 0.82rem; color: var(--muted);
  line-height: 1.65; flex: 1;
}
.section-card-arrow {
  margin-top: 1.25rem;
  font-size: 0.75rem; color: var(--muted);
  letter-spacing: 0.06em; transition: color 0.2s;
}
.section-card:hover .section-card-arrow { color: var(--white); }
 /* accent left borders per card */
.card-gold  { border-left: 3px solid #2c5f8a; border-top: none; }
.card-coral { border-left: 3px solid #2c5f8a; border-top: none; }
.card-blue  { border-left: 3px solid #4a6fa5; border-top: none; }
.card-gold2 { border-left: 3px solid #2c5f8a; border-top: none; }
.card-coral2{ border-left: 3px solid #4a6fa5; border-top: none; }
.card-blue2 { border-left: 3px solid #4a6fa5; border-top: none; }
 /*  WHAT IS D65  */
.explainer-section {
  padding: 6rem 2rem;
  background: var(--dark);
  border-top: 1px solid var(--border);
}
.explainer-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 6rem; align-items: start;
}
.explainer-inner h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 400; color: var(--white);
  line-height: 1.15; margin-bottom: 1.5rem;
}
.explainer-inner h2 em { font-style: italic; }
.explainer-inner p {
  font-size: 0.95rem; line-height: 1.85;
  color: var(--text); margin-bottom: 1.1rem;
}
.explainer-inner p:last-of-type { margin-bottom: 0; }
 /* Spec table */
.spec-table {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px; overflow: hidden;
}
.spec-table-header {
  padding: 0.75rem 1.25rem;
  background: var(--black);
  border-bottom: 1px solid var(--border);
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.65rem; color: var(--muted);
  letter-spacing: 0.15em; text-transform: uppercase;
}
.spec-row {
  display: grid; grid-template-columns: 1fr 1fr;
  border-bottom: 1px solid var(--border);
}
.spec-row:last-child { border-bottom: none; }
.spec-key, .spec-val {
  padding: 0.75rem 1.25rem;
  font-size: 0.85rem;
}
.spec-key {
  color: var(--muted);
  border-right: 1px solid var(--border);
}
.spec-val {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  color: var(--light); font-size: 0.82rem;
}
.spec-val.gold { color: var(--gold); }
.spec-val.blue { color: var(--blue); }
 /* Source citation */
.citation {
  margin-top: 1.5rem;
  padding: 1rem 1.25rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 2px solid var(--gold);
  border-radius: 0 6px 6px 0;
}
.citation p {
  font-size: 0.8rem; color: var(--muted);
  line-height: 1.6; margin: 0;
}
.citation strong { color: var(--light); font-weight: 500; }
 /*  SCIENCE SECTION  */
.science-section {
  padding: 6rem 2rem;
  background: var(--black);
  border-top: 1px solid var(--border);
}
.science-inner { max-width: 1200px; margin: 0 auto; }
.science-inner > h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 400; color: var(--white);
  margin-bottom: 3rem;
}
.science-inner > h2 em { font-style: italic; }
 .science-grid {
  display: grid; grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
}
.science-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px; padding: 1.75rem;
  transition: border-color 0.2s;
}
.science-card:hover { border-color: var(--border2); }
.science-card-tag {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.65rem; letter-spacing: 0.15em;
  text-transform: uppercase; color: var(--muted);
  margin-bottom: 0.75rem;
}
.science-card h3 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 1.1rem; font-weight: 400;
  color: var(--white); margin-bottom: 0.75rem;
  line-height: 1.3;
}
.science-card p {
  font-size: 0.85rem; color: var(--text);
  line-height: 1.75; margin-bottom: 0.75rem;
}
.science-card p:last-child { margin-bottom: 0; }
.inline-spec {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.78rem; color: var(--gold);
  background: var(--gold-dim);
  padding: 0.15rem 0.5rem; border-radius: 3px;
}
.inline-spec.blue { color: var(--blue); background: var(--blue-dim); }
.inline-spec.coral { color: var(--coral); background: var(--coral-dim); }
 /*  STANDARDS  */
.standards-section {
  padding: 6rem 2rem;
  background: var(--dark);
  border-top: 1px solid var(--border);
}
.standards-inner { max-width: 1200px; margin: 0 auto; }
.standards-inner > h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 400; color: var(--white);
  margin-bottom: 3rem;
}
.standards-inner > h2 em { font-style: italic; }
 .standards-list {
  display: flex; flex-direction: column; gap: 1px;
  border: 1px solid var(--border); border-radius: 8px;
  overflow: hidden; background: var(--border);
}
.standard-item {
  background: var(--surface);
  padding: 1.5rem 2rem;
  display: grid; grid-template-columns: 200px 1fr auto;
  gap: 2rem; align-items: center;
  transition: background 0.2s;
}
.standard-item:hover { background: var(--surface2); }
.standard-id {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.85rem; color: var(--gold);
  font-weight: 400;
}
.standard-body h4 {
  font-size: 0.92rem; font-weight: 500;
  color: var(--white); margin-bottom: 0.2rem;
}
.standard-body p {
  font-size: 0.8rem; color: var(--muted); line-height: 1.5;
}
.standard-org {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.68rem; color: var(--muted);
  letter-spacing: 0.1em; text-transform: uppercase;
  white-space: nowrap;
  background: var(--surface2);
  border: 1px solid var(--border2);
  padding: 0.3rem 0.7rem; border-radius: 4px;
}
 /*  MYTHS SECTION  */
.myths-section {
  padding: 6rem 2rem;
  background: var(--black);
  border-top: 1px solid var(--border);
}
.myths-inner { max-width: 1200px; margin: 0 auto; }
.myths-inner > h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 400; color: var(--white);
  margin-bottom: 3rem;
}
.myths-inner > h2 em { font-style: italic; }
 .myths-grid {
  display: grid; grid-template-columns: repeat(2, 1fr);
  gap: 1rem;
}
.myth-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px; padding: 1.5rem;
}
.myth-label {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.65rem; color: var(--coral);
  letter-spacing: 0.15em; text-transform: uppercase;
  margin-bottom: 0.6rem; display: flex; align-items: center; gap: 0.5rem;
}
.myth-label::before {
  content: ''; font-size: 0.6rem;
}
.fact-label {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.65rem; color: var(--blue);
  letter-spacing: 0.15em; text-transform: uppercase;
  margin-bottom: 0.4rem; margin-top: 0.75rem;
  display: flex; align-items: center; gap: 0.5rem;
}
.fact-label::before { content: ''; font-size: 0.6rem; }
.myth-card h4 {
  font-size: 0.9rem; font-weight: 400;
  color: var(--light); margin-bottom: 0.1rem;
  font-style: italic;
}
.myth-card p {
  font-size: 0.82rem; color: var(--text); line-height: 1.65;
}
.myth-divider {
  height: 1px; background: var(--border);
  margin: 0.75rem 0;
}
 /*  CALIBRATION SECTION  */
.calibration-section {
  padding: 6rem 2rem;
  background: var(--dark);
  border-top: 1px solid var(--border);
}
.calibration-inner { max-width: 1200px; margin: 0 auto; }
.calibration-inner > h2 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 400; color: var(--white);
  margin-bottom: 3rem;
}
.calibration-inner > h2 em { font-style: italic; }
 .cal-steps {
  display: flex; flex-direction: column; gap: 0;
  border: 1px solid var(--border); border-radius: 8px;
  overflow: hidden;
}
.cal-step {
  display: grid; grid-template-columns: 64px 1fr;
  border-bottom: 1px solid var(--border);
  background: var(--surface); transition: background 0.2s;
}
.cal-step:last-child { border-bottom: none; }
.cal-step:hover { background: var(--surface2); }
.cal-step-num {
  display: flex; align-items: center; justify-content: center;
  border-right: 1px solid var(--border);
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.75rem; color: var(--muted);
}
.cal-step-body { padding: 1.5rem; }
.cal-step-body h4 {
  font-size: 0.92rem; font-weight: 500;
  color: var(--white); margin-bottom: 0.3rem;
}
.cal-step-body p {
  font-size: 0.83rem; color: var(--muted); line-height: 1.6;
}
 /*  PRODUCT CTA  */
.product-cta-section {
  padding: 6rem 2rem;
  background: var(--black);
  border-top: 1px solid var(--border);
}
.product-cta-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}
.product-cta-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px; padding: 2rem;
  text-decoration: none;
  display: flex; flex-direction: column;
  transition: border-color 0.2s, transform 0.2s;
}
.product-cta-card:hover { border-color: var(--border2); transform: translateY(-2px); }
.product-cta-card.featured {
  grid-column: span 2;
  display: grid; grid-template-columns: 1fr auto;
  gap: 2rem; align-items: center;
  background: var(--surface2);
  border-color: var(--border2);
}
.product-cta-tag {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.65rem; color: var(--muted);
  letter-spacing: 0.15em; text-transform: uppercase;
  margin-bottom: 0.75rem;
}
.product-cta-card h3 {
  font-family: 'Source Serif 4', Georgia, serif;
  font-size: 1.25rem; font-weight: 400;
  color: var(--white); margin-bottom: 0.5rem;
}
.product-cta-card p {
  font-size: 0.83rem; color: var(--muted);
  line-height: 1.65; flex: 1;
}
.product-cta-specs {
  display: flex; gap: 0.5rem; flex-wrap: wrap;
  margin: 1rem 0;
}
.product-cta-spec {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.68rem; color: var(--gold);
  background: var(--gold-dim);
  padding: 0.2rem 0.55rem; border-radius: 3px;
}
.product-cta-spec.blue { color: var(--blue); background: var(--blue-dim); }
.product-link {
  margin-top: 1.25rem;
  font-size: 0.75rem; font-weight: 500;
  letter-spacing: 0.08em; text-transform: uppercase;
  color: var(--white); display: inline-flex;
  align-items: center; gap: 0.4rem;
}
.product-link-btn {
  display: inline-block;
  font-size: 0.75rem; font-weight: 500;
  letter-spacing: 0.08em; text-transform: uppercase;
  text-decoration: none; padding: 0.7rem 1.5rem;
  border-radius: 5px; background: #1a4f8a;
  color: #ffffff; white-space: nowrap;
  transition: background 0.2s;
}
.product-link-btn:hover { background: #0f3566; }
 /*  FOOTER  */
.site-footer {
  background: var(--surface);
  border-top: 1px solid var(--border);
  padding: 3rem 2rem;
}
.footer-inner {
  max-width: 1200px; margin: 0 auto;
  display: grid; grid-template-columns: 1fr 1fr 1fr;
  gap: 3rem;
}
.footer-brand .logo-d65 { font-size: 1.1rem; }
.footer-brand p {
  margin-top: 0.75rem;
  font-size: 0.8rem; color: var(--muted); line-height: 1.65;
}
.footer-col h4 {
  font-family: 'Source Code Pro', 'Courier New', monospace;
  font-size: 0.65rem; letter-spacing: 0.15em;
  text-transform: uppercase; color: var(--muted);
  margin-bottom: 1rem;
}
.footer-col a {
  display: block; text-decoration: none;
  font-size: 0.82rem; color: var(--muted);
  padding: 0.25rem 0; transition: color 0.2s;
}
.footer-col a:hover { color: var(--white); }
.footer-bottom {
  max-width: 1200px; margin: 2rem auto 0;
  padding-top: 1.5rem;
  border-top: 1px solid var(--border);
  display: flex; justify-content: space-between;
  align-items: center; flex-wrap: wrap; gap: 1rem;
}
.footer-bottom p { font-size: 0.75rem; color: var(--muted); }
.footer-bottom a { color: var(--muted); text-decoration: none; }
.footer-bottom a:hover { color: var(--white); }
 /*  ANIMATIONS  */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}
.hero-standard { animation: fadeUp 0.5s ease both; }
.hero h1       { animation: fadeUp 0.5s 0.1s ease both; }
.hero-desc     { animation: fadeUp 0.5s 0.2s ease both; }
.hero-actions  { animation: fadeUp 0.5s 0.3s ease both; }
 /*  RESPONSIVE  */
@media (max-width: 900px) {
  .hero-inner     { grid-template-columns: 1fr; gap: 2rem; }
  .explainer-inner{ grid-template-columns: 1fr; gap: 3rem; }
  .science-grid   { grid-template-columns: 1fr; }
  .myths-grid     { grid-template-columns: 1fr; }
  .sections-grid  { grid-template-columns: 1fr 1fr; }
  .standard-item  { grid-template-columns: 1fr; gap: 0.5rem; }
  .product-cta-inner { grid-template-columns: 1fr; }
  .product-cta-card.featured { grid-column: span 1; grid-template-columns: 1fr; }
  .footer-inner   { grid-template-columns: 1fr; gap: 2rem; }
  .definition-inner { grid-template-columns: 1fr; gap: 1.5rem; }
  .definition-text { border-left: none; padding-left: 0; border-top: 1px solid var(--border2); padding-top: 1.5rem; }
}
@media (max-width: 600px) {
  .sections-grid  { grid-template-columns: 1fr; }
}
   /*  MOBILE NAV  */
.hamburger {
  display: none;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
  padding: 6px;
  background: none;
  border: none;
}
.hamburger span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.25s;
}
.hamburger.open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.hamburger.open span:nth-child(2) { opacity: 0; }
.hamburger.open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }
 .mobile-menu {
  display: none;
  position: fixed;
  top: 64px;
  left: 0;
  right: 0;
  background: rgba(160,160,160,0.99);
  backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--border);
  z-index: 99;
  padding: 1rem 2rem 1.5rem;
  flex-direction: column;
  gap: 0.25rem;
}
.mobile-menu.open { display: flex; }
.mobile-menu a {
  font-size: 0.9rem;
  font-weight: 400;
  letter-spacing: 0.04em;
  color: var(--text);
  text-decoration: none;
  padding: 0.65rem 0;
  border-bottom: 1px solid var(--border);
  transition: color 0.2s;
}
.mobile-menu a:last-child { border-bottom: none; }
.mobile-menu a:hover, .mobile-menu a.active { color: var(--white); }
.mobile-menu a.active { color: var(--blue); }
.mobile-menu .mobile-cta {
  margin-top: 0.75rem;
  font-size: 0.78rem;
  font-weight: 500;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-decoration: none;
  padding: 0.7rem 1.2rem;
  border-radius: 5px;
  border: 1px solid var(--border2);
  color: var(--text);
  text-align: center;
  transition: all 0.2s;
}
.mobile-menu .mobile-cta:hover { border-color: var(--blue); color: var(--blue); }
 @media (max-width: 700px) {
  .hamburger { display: flex; }
  .main-nav { display: none !important; }
  .header-cta { display: none; }
}
 /*  GLOBAL PADDING BUFFER  */
.header-inner,
.breadcrumb-inner,
.page-hero-inner,
.page-content,
.page-nav,
.footer-inner,
.footer-bottom,
.definition-inner,
.sections-header,
.sections-grid,
.explainer-inner,
.science-inner,
.standards-inner,
.myths-inner,
.calibration-inner,
.product-cta-inner,
.hero-inner {
  padding-left: max(1.5rem, env(safe-area-inset-left));
  padding-right: max(1.5rem, env(safe-area-inset-right));
  box-sizing: border-box;
}
 /*  PAGE LAYOUT  */
.page-content { max-width: 1200px; margin: 0 auto; padding: 4rem 2rem 6rem; }
.content-grid { display: grid; grid-template-columns: 1fr 320px; gap: 4rem; align-items: start; }
.content-sidebar { position: sticky; top: 84px; }
 /*  PROSE  */
.prose h2 { font-family: 'Source Serif 4', Georgia, serif; font-size: 1.7rem; font-weight: 400; color: var(--white); margin: 2.5rem 0 1rem; line-height: 1.2; }
.prose h2:first-child { margin-top: 0; }
.prose h2 em { font-style: italic; }
.prose h3 { font-family: 'Source Serif 4', Georgia, serif; font-size: 1.15rem; font-weight: 400; color: var(--light); margin: 2rem 0 0.75rem; }
.prose p { font-size: 0.95rem; color: var(--text); line-height: 1.85; margin-bottom: 1.1rem; }
.prose p:last-child { margin-bottom: 0; }
.prose strong { color: var(--light); font-weight: 500; }
.prose a { color: #1a4f8a; text-decoration: none; border-bottom: 1px solid rgba(26,79,138,0.3); transition: border-color 0.2s; }
.prose a:hover { border-color: #1a4f8a; }
 /*  CALLOUTS  */
.callout { margin: 2rem 0; padding: 1.25rem 1.5rem; border-radius: 0 6px 6px 0; }
.callout-standard { background: rgba(0,0,0,0.06); border-left: 3px solid var(--gold); }
.callout-note     { background: rgba(0,0,0,0.06); border-left: 3px solid var(--blue); }
.callout-warning  { background: rgba(0,0,0,0.06); border-left: 3px solid var(--coral); }
.callout p { font-size: 0.85rem; color: var(--text); line-height: 1.7; margin: 0; }
.callout strong { color: var(--white); }
.callout-label { font-family: 'Source Code Pro', monospace; font-size: 0.62rem; letter-spacing: 0.15em; text-transform: uppercase; color: var(--muted); margin-bottom: 0.5rem; display: block; }
 /*  SPEC TABLE  */
.spec-table { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; overflow: hidden; margin: 2rem 0; }
.spec-table-header { padding: 0.75rem 1.25rem; background: rgba(0,0,0,0.12); border-bottom: 1px solid var(--border); font-family: 'Source Code Pro', monospace; font-size: 0.65rem; color: var(--muted); letter-spacing: 0.15em; text-transform: uppercase; }
.spec-row { display: grid; grid-template-columns: 1fr 1fr; border-bottom: 1px solid var(--border); }
.spec-row:last-child { border-bottom: none; }
.spec-key { padding: 0.75rem 1.25rem; font-size: 0.85rem; color: var(--muted); border-right: 1px solid var(--border); }
.spec-val { padding: 0.75rem 1.25rem; font-family: 'Source Code Pro', monospace; color: var(--light); font-size: 0.82rem; }
.spec-val.gold  { color: var(--gold); }
.spec-val.blue  { color: var(--blue); }
.spec-val.coral { color: var(--coral); }
 /*  INLINE CODE  */
.inline-spec { font-family: 'Source Code Pro', monospace; font-size: 0.82rem; color: var(--gold); background: var(--gold-dim); padding: 0.1rem 0.45rem; border-radius: 3px; }
.inline-spec.blue  { color: var(--blue);  background: var(--blue-dim); }
.inline-spec.coral { color: var(--coral); background: var(--coral-dim); }
 /*  SIDEBAR  */
.sidebar-card { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; overflow: hidden; margin-bottom: 1.25rem; }
.sidebar-card-header { padding: 0.75rem 1.25rem; background: rgba(0,0,0,0.12); border-bottom: 1px solid var(--border); font-family: 'Source Code Pro', monospace; font-size: 0.62rem; color: var(--muted); letter-spacing: 0.15em; text-transform: uppercase; }
.sidebar-card-body { padding: 1.25rem; }
.sidebar-nav a { display: block; font-size: 0.82rem; color: var(--muted); text-decoration: none; padding: 0.4rem 0; border-bottom: 1px solid var(--border); transition: color 0.2s; }
.sidebar-nav a:last-child { border-bottom: none; }
.sidebar-nav a:hover { color: var(--white); }
.sidebar-nav a.active { color: var(--gold); }
.sidebar-card-body p { font-size: 0.82rem; color: var(--muted); line-height: 1.65; }
.sidebar-card-body .btn-sm { display: inline-block; margin-top: 0.75rem; font-size: 0.72rem; font-weight: 500; letter-spacing: 0.08em; text-transform: uppercase; text-decoration: none; padding: 0.5rem 1rem; border-radius: 4px; background: #1a4f8a; color: #fff; transition: background 0.2s; }
.sidebar-card-body .btn-sm:hover { background: #0f3566; }
 /*  SECTION DIVIDER  */
.section-divider { height: 1px; background: var(--border); margin: 3rem 0; }
 /*  PREV/NEXT NAV  */
.page-nav { max-width: 1200px; margin: 0 auto; padding: 0 2rem 4rem; display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap; }
.page-nav-item { background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 1.25rem 1.5rem; text-decoration: none; flex: 1; min-width: 200px; transition: border-color 0.2s; }
.page-nav-item:hover { border-color: var(--border2); }
.page-nav-label { font-family: 'Source Code Pro', monospace; font-size: 0.62rem; color: var(--muted); letter-spacing: 0.12em; text-transform: uppercase; margin-bottom: 0.4rem; }
.page-nav-title { font-size: 0.9rem; color: var(--white); }
.page-nav-item.next { text-align: right; }
 /*  PAGE HERO  */
.page-hero { padding: 5rem 2rem 4rem; background: var(--dark); border-bottom: 1px solid var(--border); position: relative; overflow: hidden; }
.page-hero-inner { max-width: 1200px; margin: 0 auto; position: relative; z-index: 1; }
.page-eyebrow { font-family: 'Source Code Pro', monospace; font-size: 0.68rem; color: var(--gold); letter-spacing: 0.2em; text-transform: uppercase; margin-bottom: 1.25rem; display: flex; align-items: center; gap: 0.75rem; }
.page-eyebrow::before { content: ''; display: block; width: 24px; height: 1px; background: var(--gold); }
.page-hero h1 { font-family: 'Source Serif 4', Georgia, serif; font-size: clamp(2.4rem, 5vw, 3.8rem); font-weight: 400; color: var(--white); line-height: 1.1; letter-spacing: -0.01em; margin-bottom: 1.25rem; max-width: 800px; }
.page-hero h1 em { font-style: italic; }
.page-hero-desc { font-size: 1.05rem; color: var(--text); line-height: 1.85; max-width: 680px; }
.page-hero-meta { margin-top: 2rem; display: flex; gap: 2rem; flex-wrap: wrap; }
.page-meta-item { font-family: 'Source Code Pro', monospace; font-size: 0.7rem; color: var(--muted); }
.page-meta-item strong { color: var(--gold); display: block; margin-bottom: 0.2rem; }
 /*  BREADCRUMB  */
.breadcrumb { background: var(--surface); border-bottom: 1px solid var(--border); padding: 0.65rem 2rem; }
.breadcrumb-inner { max-width: 1200px; margin: 0 auto; display: flex; gap: 0.5rem; align-items: center; font-family: 'Source Code Pro', monospace; font-size: 0.68rem; color: var(--muted); }
.breadcrumb-inner a { color: var(--muted); text-decoration: none; transition: color 0.2s; }
.breadcrumb-inner a:hover { color: var(--white); }
.breadcrumb-inner span { opacity: 0.4; }
 /*  RESPONSIVE: collapse sidebar below content  */
@media (max-width: 900px) {
  .content-grid { grid-template-columns: 1fr; }
  .content-sidebar { position: static; }
}