/* ============================================================
   Melanotan Source — Drill Down Analytics Aesthetic
   Deep cool slate-indigo console, four drill-tier accent system
   Archivo (display) + IBM Plex Sans (body) + IBM Plex Mono (identifiers)
   ============================================================ */

/* ---- Custom properties ---- */
:root {
  /* Palette */
  --primary:          #4C8DFF;
  --primary-50:       #1B2440;
  --primary-100:      #22305A;
  --primary-300:      #3B6FD6;
  --primary-500:      #4C8DFF;
  --primary-700:      #7CADFF;
  --primary-900:      #B9D2FF;
  --secondary:        #2DD4BF;
  --accent:           #F5A524;
  --accent-pink:      #F471B5;

  /* Drill-tier accents */
  --tier-clinical:    #4C8DFF;
  --tier-preclinical: #2DD4BF;
  --tier-regulatory:  #F5A524;
  --tier-safety:      #F471B5;

  /* Surfaces (three elevation levels = drill depth) */
  --bg:               #0E1320;
  --bg-elev-1:        #141B2D;
  --bg-elev-2:        #1C2540;
  --surface:          #141B2D;
  --surface-inset:    #0A0E18;
  --surface-drill:    #1C2540;

  /* Neutral scale */
  --neutral-50:       #0A0E18;
  --neutral-100:      #0E1320;
  --neutral-200:      #141B2D;
  --neutral-300:      #1C2540;
  --neutral-400:      #283454;
  --neutral-500:      #5A6788;
  --neutral-600:      #7C89A8;
  --neutral-700:      #A6B2CE;
  --neutral-900:      #E6ECF7;

  /* Text */
  --text:             #E6ECF7;
  --text-muted:       #A6B2CE;
  --text-dim:         #7C89A8;
  --text-on-accent:   #0A0E18;

  /* Rules */
  --rule:             #283454;
  --rule-strong:      #3B6FD6;

  /* Links */
  --link:             #7CADFF;
  --link-visited:     #B9D2FF;

  /* Typography */
  --font-heading:     'Archivo', 'Helvetica Neue', Inter, system-ui, -apple-system, sans-serif;
  --font-body:        'IBM Plex Sans', system-ui, -apple-system, 'Segoe UI', sans-serif;
  --font-mono:        'IBM Plex Mono', 'SF Mono', Menlo, Consolas, monospace;

  /* Scale */
  --scale-metric-display: clamp(2.5rem, 6vw, 4.25rem);
  --scale-metric-kpi:     clamp(1.5rem, 3vw, 2.25rem);
  --scale-h1:             clamp(2rem, 4.25vw, 3.25rem);
  --scale-h2:             clamp(1.5rem, 3vw, 2.25rem);
  --scale-h3:             1.3125rem;
  --scale-h4:             1.0625rem;
  --scale-lede:           1.1875rem;
  --scale-body:           1.0625rem;
  --scale-small:          0.875rem;
  --scale-micro:          0.8125rem;
  --scale-breadcrumb:     0.8125rem;
  --scale-nav:            0.9375rem;

  /* Layout */
  --max-width:        76rem;
  --container-px:     clamp(1rem, 3.5vw, 2.5rem);

  /* Misc */
  --radius-button:    9999px;
  --radius-card:      0.625rem;
  --transition-fast:  180ms ease-out;
}

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

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

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }
  *,
  *::before,
  *::after {
    transition-duration: 0ms !important;
    animation-duration: 0ms !important;
  }
}

body {
  font-family: var(--font-body);
  font-size: var(--scale-body);
  line-height: 1.7;
  color: var(--text);
  background-color: var(--bg);
  -webkit-font-smoothing: antialiased;
  font-feature-settings: "kern" 1, "liga" 1;
}

/* ---- Typography ---- */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.18;
  color: var(--text);
}

h1 {
  font-size: var(--scale-h1);
  font-weight: 700;
  line-height: 1.14;
  letter-spacing: -0.015em;
}

h2 {
  font-size: var(--scale-h2);
  font-weight: 700;
  letter-spacing: -0.02em;
}

h3 {
  font-size: var(--scale-h3);
  font-weight: 600;
  letter-spacing: -0.01em;
}

h4 {
  font-size: var(--scale-h4);
  font-weight: 600;
}

p {
  max-width: 40rem;
  margin-bottom: 1.25rem;
}

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

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

a:visited {
  color: var(--link-visited);
}

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

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

strong {
  font-weight: 600;
  color: var(--text);
}

em {
  font-style: italic;
  color: var(--text-muted);
}

code,
.mono {
  font-family: var(--font-mono);
  font-size: 0.9em;
  background-color: var(--surface-inset);
  border-radius: 0.25rem;
  padding: 0.0625rem 0.375rem;
  color: var(--text-muted);
  font-feature-settings: "tnum" 1;
}

ul, ol {
  padding-left: 1.5rem;
  margin-bottom: 1.25rem;
}

ul {
  list-style: none;
  padding-left: 0;
}

ul li {
  padding-left: 1.25rem;
  position: relative;
  margin-bottom: 0.5rem;
}

ul li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0.6em;
  width: 6px;
  height: 6px;
  background-color: var(--primary);
  flex-shrink: 0;
}

ol {
  counter-reset: item;
  list-style: none;
  padding-left: 0;
}

ol li {
  counter-increment: item;
  padding-left: 2rem;
  position: relative;
  margin-bottom: 0.625rem;
}

ol li::before {
  content: counter(item) ".";
  position: absolute;
  left: 0;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--primary);
  font-feature-settings: "tnum" 1;
  min-width: 1.5rem;
}

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

/* ---- Skip link ---- */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 9999;
  padding: 0.75rem 1rem;
  background: var(--primary);
  color: var(--text-on-accent);
  font-weight: 600;
  border-radius: 0 0 var(--radius-card) 0;
}

.skip-link:focus {
  left: 0;
}

/* ---- Site Header ---- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: 60px;
  background-color: var(--bg-elev-1);
  border-bottom: 1px solid var(--rule);
  display: flex;
  align-items: center;
}

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

/* Wordmark */
.site-brand {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-family: var(--font-heading);
  font-size: var(--scale-body);
  font-weight: 700;
  color: var(--text);
  text-decoration: none;
  white-space: nowrap;
}

.site-brand:visited {
  color: var(--text);
}

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

.wordmark-mark {
  display: inline-block;
  width: 9px;
  height: 9px;
  background-color: var(--primary);
  flex-shrink: 0;
}

/* Primary nav */
.site-nav {
  display: flex;
  align-items: center;
}

.site-nav ul {
  display: flex;
  gap: 1.5rem;
  list-style: none;
  padding: 0;
  margin: 0;
}

.site-nav ul li {
  padding: 0;
  margin: 0;
}

.site-nav ul li::before {
  display: none;
}

.site-nav a {
  font-family: var(--font-body);
  font-size: var(--scale-nav);
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  letter-spacing: 0.01em;
  padding-bottom: 2px;
  border-bottom: 2px solid transparent;
  transition: color var(--transition-fast), border-color var(--transition-fast);
}

.site-nav a:hover,
.site-nav a[aria-current="page"] {
  color: var(--text);
  border-bottom-color: var(--primary);
}

/* Mobile nav disclosure */
.nav-disclosure {
  display: none;
}

.nav-disclosure summary {
  list-style: none;
  cursor: pointer;
  font-family: var(--font-body);
  font-size: var(--scale-nav);
  font-weight: 500;
  color: var(--text-muted);
  padding: 0.5rem 0;
}

.nav-disclosure summary::-webkit-details-marker {
  display: none;
}

.nav-disclosure summary:focus-visible {
  outline: 2px solid var(--primary-700);
  outline-offset: 3px;
}

.nav-mobile-list {
  position: absolute;
  top: 60px;
  left: 0;
  right: 0;
  background-color: var(--bg-elev-1);
  border-bottom: 1px solid var(--rule);
  padding: 1rem var(--container-px);
  display: flex;
  flex-direction: column;
  gap: 0;
  z-index: 99;
}

.nav-mobile-list li {
  padding: 0;
  margin: 0;
}

.nav-mobile-list li::before {
  display: none;
}

.nav-mobile-list a {
  display: block;
  padding: 0.75rem 0;
  font-family: var(--font-body);
  font-size: var(--scale-body);
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  border-bottom: 1px solid var(--rule);
  transition: color var(--transition-fast);
}

.nav-mobile-list a:last-of-type {
  border-bottom: none;
}

.nav-mobile-list a:hover {
  color: var(--text);
}

@media (max-width: 880px) {
  .site-nav-desktop {
    display: none;
  }
  .nav-disclosure {
    display: block;
    position: relative;
  }
}

@media (min-width: 881px) {
  .nav-disclosure {
    display: none;
  }
}

/* ---- Main ---- */
main {
  min-height: 60vh;
}

/* ---- Breadcrumb drill-path ---- */
.breadcrumb-drill {
  font-family: var(--font-mono);
  font-size: var(--scale-breadcrumb);
  font-weight: 500;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 1rem;
  display: block;
}

.breadcrumb-drill .caret {
  color: var(--primary);
  margin-inline: 0.4em;
}

.breadcrumb-drill .crumb-current {
  color: var(--text);
}

/* ---- Hero ---- */
.hero {
  padding-block: clamp(3rem, 7vw, 5.5rem);
  padding-inline: var(--container-px);
  max-width: var(--max-width);
  margin-inline: auto;
}

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

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

.hero .eyebrow {
  font-size: var(--scale-small);
  font-family: var(--font-body);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.hero .subheadline {
  font-size: var(--scale-lede);
  font-family: var(--font-body);
  font-weight: 400;
  color: var(--text-muted);
  line-height: 1.5;
  max-width: 36rem;
  margin-top: 1rem;
  margin-bottom: 1.5rem;
}

/* CTA row */
.cta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.8125rem 1.625rem;
  border-radius: var(--radius-button);
  font-family: var(--font-body);
  font-size: var(--scale-nav);
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  border: none;
  transition: background-color var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
}

.btn:focus-visible {
  outline: 2px solid var(--primary-700);
  outline-offset: 3px;
}

.btn-primary {
  background-color: var(--primary);
  color: var(--text-on-accent);
  border: none;
}

.btn-primary:hover {
  background-color: var(--primary-700);
  color: var(--text-on-accent);
}

.btn-secondary {
  background-color: transparent;
  color: var(--primary-700);
  border: 1.5px solid var(--primary);
}

.btn-secondary:visited {
  color: var(--primary-700);
}

.btn-secondary:hover {
  background-color: var(--primary-50);
  color: var(--primary-700);
}

.btn-ghost {
  background-color: transparent;
  color: var(--primary-700);
  border: none;
  padding: 0;
  text-decoration: underline;
  text-underline-offset: 3px;
  border-radius: 0;
}

.btn-ghost:hover {
  color: var(--text);
}

/* ---- KPI Parent-metric strip ---- */
.kpi-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 2rem;
}

.kpi-tile {
  background-color: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  padding: 0.875rem 1.25rem;
  min-width: 9rem;
  position: relative;
  overflow: hidden;
}

.kpi-tile::before {
  content: '';
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
}

.kpi-tile.tier-clinical::before  { background-color: var(--tier-clinical); }
.kpi-tile.tier-preclinical::before { background-color: var(--tier-preclinical); }
.kpi-tile.tier-regulatory::before { background-color: var(--tier-regulatory); }
.kpi-tile.tier-safety::before   { background-color: var(--tier-safety); }

.kpi-value {
  font-family: var(--font-heading);
  font-size: var(--scale-metric-kpi);
  font-weight: 800;
  line-height: 0.98;
  display: block;
  font-feature-settings: "tnum" 1;
  margin-bottom: 0.375rem;
}

.kpi-tile.tier-clinical   .kpi-value { color: var(--tier-clinical); }
.kpi-tile.tier-preclinical .kpi-value { color: var(--tier-preclinical); }
.kpi-tile.tier-regulatory .kpi-value { color: var(--tier-regulatory); }
.kpi-tile.tier-safety     .kpi-value { color: var(--tier-safety); }

.kpi-unit {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  color: var(--text-dim);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  display: block;
  font-feature-settings: "tnum" 1;
}

/* ---- Hero data-illustration band ---- */
.hero-figure {
  width: 100%;
  margin-block: 3rem;
  border-top: 1px solid var(--rule);
  border-bottom: 1px solid var(--rule);
}

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

/* ---- Page body layout ---- */
.page-body {
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--container-px);
  padding-bottom: 4rem;
}

/* With sidebar layout */
.page-body-with-sidebar {
  display: grid;
  grid-template-columns: 1fr;
  gap: 3rem;
}

@media (min-width: 1080px) {
  .page-body-with-sidebar {
    grid-template-columns: 1fr 14rem;
    align-items: start;
  }
}

.page-body-main {
  min-width: 0;
}

.page-body-sidebar {
  display: none;
}

@media (min-width: 1080px) {
  .page-body-sidebar {
    display: block;
    position: sticky;
    top: 80px;
  }
}

/* Drill map sidebar */
.drill-map {
  background-color: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  padding: 1rem;
}

.drill-map-title {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--primary);
  margin-bottom: 0.75rem;
}

.drill-map-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.drill-map-list li {
  padding: 0;
  margin-bottom: 0.375rem;
}

.drill-map-list li::before {
  display: none;
}

.drill-map-list a {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  color: var(--text-dim);
  text-decoration: none;
  display: block;
  padding: 0.25rem 0;
  transition: color var(--transition-fast);
}

.drill-map-list a:hover {
  color: var(--text-muted);
}

/* ---- Tier section header ---- */
.tier-section {
  margin-bottom: 3rem;
}

.tier-eyebrow {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  margin-bottom: 0.5rem;
  display: block;
}

.tier-clinical   .tier-eyebrow { color: var(--tier-clinical); }
.tier-preclinical .tier-eyebrow { color: var(--tier-preclinical); }
.tier-regulatory .tier-eyebrow { color: var(--tier-regulatory); }
.tier-safety     .tier-eyebrow { color: var(--tier-safety); }

.tier-section > h2 {
  margin-bottom: 0.5rem;
}

.tier-accent-rule {
  height: 2px;
  width: 2rem;
  border: none;
  margin: 0.75rem 0 1.25rem;
}

.tier-clinical   .tier-accent-rule { background-color: var(--tier-clinical); }
.tier-preclinical .tier-accent-rule { background-color: var(--tier-preclinical); }
.tier-regulatory .tier-accent-rule { background-color: var(--tier-regulatory); }
.tier-safety     .tier-accent-rule { background-color: var(--tier-safety); }

.tier-summary {
  margin-bottom: 1.5rem;
  color: var(--text-muted);
  font-size: var(--scale-body);
  max-width: 40rem;
}

/* ---- Drill rows (<details>/<summary>) ---- */
.drill-row {
  background-color: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  margin-bottom: 0.5rem;
  overflow: hidden;
  transition: border-color var(--transition-fast);
}

.drill-row:hover {
  border-color: var(--rule-strong);
}

.drill-row[open] {
  border-color: var(--rule-strong);
}

.drill-row > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.875rem 1.125rem;
  cursor: pointer;
  list-style: none;
  user-select: none;
}

.drill-row > summary::-webkit-details-marker {
  display: none;
}

.drill-row > summary:focus-visible {
  outline: 2px solid var(--primary-700);
  outline-offset: -3px;
  border-left: 2px solid var(--primary);
}

.drill-summary-left {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  min-width: 0;
}

.drill-caret {
  width: 0;
  height: 0;
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  border-left: 7px solid var(--primary);
  flex-shrink: 0;
  transition: transform var(--transition-fast);
}

.tier-preclinical .drill-caret { border-left-color: var(--tier-preclinical); }
.tier-regulatory  .drill-caret { border-left-color: var(--tier-regulatory); }
.tier-safety      .drill-caret { border-left-color: var(--tier-safety); }

.drill-row[open] .drill-caret {
  transform: rotate(90deg);
}

.drill-title {
  font-family: var(--font-heading);
  font-size: var(--scale-h4);
  font-weight: 600;
  color: var(--text);
  line-height: 1.3;
}

.drill-metric {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  white-space: nowrap;
  flex-shrink: 0;
  font-feature-settings: "tnum" 1;
}

.tier-clinical   .drill-metric { color: var(--tier-clinical); }
.tier-preclinical .drill-metric { color: var(--tier-preclinical); }
.tier-regulatory .drill-metric { color: var(--tier-regulatory); }
.tier-safety     .drill-metric { color: var(--tier-safety); }

.drill-panel {
  padding: 1rem 1.125rem 1.25rem;
  background-color: var(--surface-drill);
  border-top: 1px solid var(--rule);
}

.drill-panel p {
  color: var(--text);
  font-size: var(--scale-body);
  line-height: 1.7;
  max-width: 40rem;
}

/* ---- Citation superscripts ---- */
sup a[data-citation] {
  font-family: var(--font-mono);
  font-size: 0.65em;
  font-weight: 600;
  color: var(--primary-700);
  text-decoration: none;
  vertical-align: super;
  padding: 0 0.1em;
  transition: color var(--transition-fast);
}

sup a[data-citation]:hover {
  color: var(--text);
}

/* ---- Callout boxes ---- */
.callout {
  background-color: var(--surface);
  border: 1px solid var(--rule);
  border-left-width: 3px;
  border-radius: 0 var(--radius-card) var(--radius-card) 0;
  padding: 1rem 1.25rem;
  margin-block: 1.5rem;
  max-width: 40rem;
}

.callout-eyebrow {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  margin-bottom: 0.5rem;
  display: block;
}

.callout-clinical    { border-left-color: var(--tier-clinical); }
.callout-preclinical { border-left-color: var(--tier-preclinical); }
.callout-regulatory  { border-left-color: var(--tier-regulatory); }
.callout-safety      { border-left-color: var(--tier-safety); }

.callout-clinical    .callout-eyebrow { color: var(--tier-clinical); }
.callout-preclinical .callout-eyebrow { color: var(--tier-preclinical); }
.callout-regulatory  .callout-eyebrow { color: var(--tier-regulatory); }
.callout-safety      .callout-eyebrow { color: var(--tier-safety); }

/* ---- Section divider ---- */
.section-divider {
  border: none;
  border-top: 1px solid var(--rule);
  margin-block: 2.5rem;
}

/* ---- Figure images ---- */
.content-figure {
  margin-block: 2rem;
  background-color: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  overflow: hidden;
}

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

.content-figure figcaption {
  padding: 0.75rem 1rem;
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  color: var(--text-dim);
  border-top: 1px solid var(--rule);
  letter-spacing: 0.04em;
}

/* ---- FAQ accordion ---- */
.faq-section {
  margin-bottom: 2.5rem;
}

.faq-section-heading {
  margin-bottom: 1rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--rule);
}

.faq-item {
  background-color: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  margin-bottom: 0.5rem;
  overflow: hidden;
}

.faq-item:hover {
  border-color: var(--rule-strong);
}

.faq-item[open] {
  border-color: var(--rule-strong);
}

.faq-item > summary {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 1rem 1.125rem;
  cursor: pointer;
  list-style: none;
  font-family: var(--font-heading);
  font-size: var(--scale-h4);
  font-weight: 600;
  color: var(--text);
  line-height: 1.4;
}

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

.faq-item > summary:focus-visible {
  outline: 2px solid var(--primary-700);
  outline-offset: -3px;
}

.faq-caret {
  width: 0;
  height: 0;
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  border-left: 7px solid var(--primary);
  flex-shrink: 0;
  margin-top: 0.4em;
  transition: transform var(--transition-fast);
}

.faq-item[open] .faq-caret {
  transform: rotate(90deg);
}

.faq-answer {
  padding: 0.75rem 1.125rem 1.125rem;
  background-color: var(--surface-drill);
  border-top: 1px solid var(--rule);
  color: var(--text);
  font-size: var(--scale-body);
  line-height: 1.7;
  max-width: 40rem;
}

/* ---- References list ---- */
.references-intro {
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  max-width: 40rem;
}

.references-filter-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
}

.filter-chip {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  padding: 0.375rem 0.75rem;
  border-radius: 0.375rem;
  cursor: pointer;
  border: 1px solid var(--rule);
  background-color: transparent;
  color: var(--text-dim);
  transition: color var(--transition-fast), border-color var(--transition-fast), background-color var(--transition-fast);
}

.filter-chip.active,
.filter-chip:hover {
  color: var(--primary);
  border-color: var(--primary);
  background-color: var(--primary-50);
}

#references-table-wrapper {
  overflow-x: auto;
}

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

.references-list li {
  padding: 1rem 0;
  border-bottom: 1px solid var(--rule);
  counter-increment: refs;
  display: grid;
  grid-template-columns: 2.5rem 1fr;
  gap: 0.75rem;
  padding-left: 0;
  margin-bottom: 0;
}

.references-list li::before {
  display: none;
}

.ref-num {
  font-family: var(--font-mono);
  font-size: var(--scale-small);
  font-weight: 600;
  color: var(--primary);
  font-feature-settings: "tnum" 1;
  padding-top: 0.1em;
}

.ref-body {
  min-width: 0;
}

.ref-citation {
  font-family: var(--font-body);
  font-size: var(--scale-small);
  color: var(--text-muted);
  margin-bottom: 0.375rem;
  line-height: 1.55;
}

.ref-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
}

.ref-type-chip {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  font-weight: 500;
  padding: 0.1875rem 0.5rem;
  border-radius: 0.25rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

.ref-type-clinical    { border: 1px solid var(--tier-clinical);    color: var(--tier-clinical); }
.ref-type-preclinical { border: 1px solid var(--tier-preclinical); color: var(--tier-preclinical); }
.ref-type-case-report { border: 1px solid var(--tier-safety);     color: var(--tier-safety); }
.ref-type-review      { border: 1px solid var(--tier-regulatory);  color: var(--tier-regulatory); }
.ref-type-observational { border: 1px solid var(--text-dim);       color: var(--text-dim); }

.ref-link {
  font-family: var(--font-mono);
  font-size: 0.6875rem;
  color: var(--link);
  text-decoration: none;
  font-feature-settings: "tnum" 1;
  transition: color var(--transition-fast);
}

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

/* ---- Contact form ---- */
.contact-form {
  max-width: 36rem;
  margin-top: 2rem;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-label {
  display: block;
  font-family: var(--font-body);
  font-size: var(--scale-small);
  font-weight: 500;
  color: var(--text-muted);
  margin-bottom: 0.375rem;
}

.form-input,
.form-textarea {
  width: 100%;
  background-color: var(--surface);
  border: 1px solid var(--rule);
  border-radius: var(--radius-card);
  padding: 0.75rem 1rem;
  font-family: var(--font-body);
  font-size: var(--scale-body);
  color: var(--text);
  transition: border-color var(--transition-fast);
  appearance: none;
  -webkit-appearance: none;
}

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

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

/* ---- Tippy theme overrides ---- */
.tippy-box[data-theme~='melanotan'] {
  background-color: var(--surface);
  border: 1px solid var(--primary);
  color: var(--text);
  font-family: var(--font-body);
  font-size: var(--scale-small);
  border-radius: var(--radius-card);
}

.tippy-box[data-theme~='melanotan'] .tippy-content {
  padding: 0.75rem;
}

.tippy-box[data-theme~='melanotan'][data-placement^='top'] .tippy-arrow::before {
  border-top-color: var(--primary);
}

/* ---- 404 ---- */
.error-page {
  padding-block: 6rem;
  text-align: center;
}

.error-code {
  font-family: var(--font-heading);
  font-size: var(--scale-metric-display);
  font-weight: 800;
  color: var(--primary);
  display: block;
  margin-bottom: 1rem;
  font-feature-settings: "tnum" 1;
}

/* ---- Site Footer ---- */
.site-footer {
  background-color: var(--surface-inset);
  border-top: 1px solid var(--rule);
  padding-top: 2.5rem;
  padding-bottom: 2rem;
}

.footer-disclaimer {
  font-family: var(--font-body);
  font-size: var(--scale-small);
  font-style: italic;
  color: var(--text-muted);
  margin-bottom: 1.5rem;
  max-width: 60rem;
}

.footer-rule {
  border: none;
  border-top: 1px solid var(--primary);
  margin-bottom: 2rem;
  opacity: 0.4;
}

.footer-columns {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(10rem, 1fr));
  gap: 2rem;
  margin-bottom: 2.5rem;
}

.footer-col-heading {
  font-family: var(--font-mono);
  font-size: var(--scale-micro);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--primary);
  margin-bottom: 0.75rem;
}

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

.footer-col-links li {
  padding: 0;
  margin-bottom: 0.5rem;
}

.footer-col-links li::before {
  display: none;
}

.footer-col-links a {
  font-family: var(--font-body);
  font-size: var(--scale-small);
  font-weight: 500;
  color: var(--text-muted);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

.footer-wordmark {
  font-family: var(--font-heading);
  font-size: var(--scale-body);
  font-weight: 700;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
  margin-bottom: 0.5rem;
}

.footer-colophon {
  font-size: var(--scale-micro);
  color: var(--text-dim);
  line-height: 1.6;
}

.footer-copyright {
  font-size: var(--scale-micro);
  color: var(--text-dim);
  margin-top: 0.25rem;
}

/* ---- Reading prose sections ---- */
.prose {
  max-width: 40rem;
}

.prose p,
.prose ul,
.prose ol {
  margin-bottom: 1.25rem;
}

.prose h3 {
  margin-top: 2rem;
  margin-bottom: 0.75rem;
}

.prose h4 {
  margin-top: 1.5rem;
  margin-bottom: 0.5rem;
}

/* ---- Responsive ---- */
@media (max-width: 720px) {
  .kpi-strip {
    flex-direction: column;
  }
  .kpi-tile {
    min-width: unset;
  }
  .footer-columns {
    grid-template-columns: 1fr 1fr;
  }
  .references-list li {
    grid-template-columns: 2rem 1fr;
  }
}

@media (max-width: 480px) {
  .footer-columns {
    grid-template-columns: 1fr;
  }
  .cta-row {
    flex-direction: column;
  }
  .btn {
    text-align: center;
    width: 100%;
    justify-content: center;
  }
}