/* ============================================================
   Plainly Medicine
   Bold editorial magazine. Cream ground, enormous type,
   saturated full-bleed colour blocks, anatomical diagrams.
   ============================================================ */

:root {
  --paper:   #F7F3EA;
  --paper-2: #EFE9DC;
  --ink:     #14110D;
  --ink-2:   #3D372E;
  --muted:   #6B6357;
  --faint:   #9C9384;
  --rule:    #DCD4C4;
  --rule-2:  #C7BDA8;

  --display: "Fraunces", Georgia, serif;
  --sans: "IBM Plex Sans", system-ui, -apple-system, sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, SFMono-Regular, monospace;

  --measure: 66ch;
  --pad: clamp(1.25rem, 5vw, 4.5rem);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);

  --c-cardiology:   #D8262E;
  --c-neurology:    #7857E0;
  --c-oncology:     #D1276E;
  --c-metabolic:    #A2601C;
  --c-infectious:   #198125;
  --c-criticalcare: #1F77A2;
  --c-transplant:   #18804F;
  --c-longevity:    #91691B;
  --c-editing:      #5064DE;
}

[data-theme="dark"] {
  --paper:   #14110D;
  --paper-2: #1D1913;
  --ink:     #F7F3EA;
  --ink-2:   #DCD4C4;
  --muted:   #A79D8C;
  --faint:   #6B6357;
  --rule:    #2C2720;
  --rule-2:  #3D372E;

  --c-cardiology:   #E4646A;
  --c-neurology:    #9B82E8;
  --c-oncology:     #E36A9C;
  --c-metabolic:    #E0964A;
  --c-infectious:   #63B96D;
  --c-criticalcare: #52A6CE;
  --c-transplant:   #46C88A;
  --c-longevity:    #DBA53E;
  --c-editing:      #6F7FE0;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { animation: none !important; transition: none !important; }
}

body {
  background: var(--paper); color: var(--ink);
  font-family: var(--sans); font-size: 1.05rem; line-height: 1.65;
  -webkit-font-smoothing: antialiased; text-rendering: optimizeLegibility;
}

h1, h2, h3 {
  font-family: var(--display); font-weight: 900;
  font-variation-settings: "opsz" 144, "SOFT" 0, "WONK" 1;
  line-height: 0.92; letter-spacing: -0.035em;
}
a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }
::selection { background: var(--ink); color: var(--paper); }

.wrap { width: 100%; max-width: 1760px; margin-inline: auto; padding-inline: var(--pad); }
.narrow { max-width: 720px; }

.label {
  font-family: var(--mono); font-size: 0.7rem; font-weight: 500;
  letter-spacing: 0.22em; text-transform: uppercase;
}

/* ---------------- nav ---------------- */
.nav {
  position: sticky; top: 0; z-index: 100; background: var(--paper);
  border-bottom: 2px solid var(--ink);
}
.nav-inner { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.wordmark { font-family: var(--display); font-weight: 900; font-size: 1.25rem; letter-spacing: -0.02em; }
.nav-links { display: flex; align-items: center; gap: 2rem; }
.nav-links a {
  font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--ink); position: relative; padding: 4px 0;
}
.nav-links a::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: 0; height: 2px;
  background: var(--ink); transition: right 0.35s var(--ease);
}
.nav-links a:hover::after, .nav-links a[aria-current="page"]::after { right: 0; }
.nav-tools { display: flex; align-items: center; gap: 0.6rem; }
.theme-toggle {
  width: 38px; height: 38px; border-radius: 0; border: 2px solid var(--ink);
  background: transparent; color: var(--ink); display: grid; place-items: center;
  cursor: pointer; transition: background 0.2s, color 0.2s;
}
.theme-toggle:hover { background: var(--ink); color: var(--paper); }
.theme-toggle svg { width: 17px; height: 17px; }
.theme-toggle .sun { display: none; }
[data-theme="dark"] .theme-toggle .sun { display: block; }
[data-theme="dark"] .theme-toggle .moon { display: none; }
.menu-btn { display: none; background: none; border: 0; color: var(--ink); cursor: pointer; padding: 6px; }
.menu-btn svg { width: 24px; height: 24px; }

/* ---------------- masthead ---------------- */
.masthead { padding-block: clamp(2.5rem, 6vw, 4.5rem) clamp(2rem, 5vw, 3.5rem); border-bottom: 2px solid var(--ink); }
.masthead-meta {
  display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
  padding-bottom: 1.5rem; border-bottom: 1px solid var(--rule); color: var(--muted);
}
.masthead h1 {
  font-size: clamp(3.4rem, 13vw, 12rem); margin-top: clamp(1.5rem, 4vw, 3rem);
  letter-spacing: -0.045em; max-width: 14ch;
}
.masthead .standfirst {
  font-size: clamp(1.15rem, 2.2vw, 1.6rem); line-height: 1.4; color: var(--ink-2);
  max-width: 42ch; margin-top: 2rem; font-family: var(--display); font-weight: 700;
  font-variation-settings: "opsz" 40, "SOFT" 20, "WONK" 0;
}
.masthead .deck { color: var(--muted); max-width: 52ch; margin-top: 1.5rem; }
.masthead .actions { display: flex; gap: 0.9rem; flex-wrap: wrap; margin-top: 2.5rem; }

/* ---------------- buttons ---------------- */
.btn {
  display: inline-flex; align-items: center; gap: 0.6rem; font-family: var(--mono);
  font-size: 0.74rem; letter-spacing: 0.14em; text-transform: uppercase;
  padding: 1rem 1.75rem; cursor: pointer; border: 2px solid var(--ink);
  background: var(--ink); color: var(--paper); transition: background 0.2s, color 0.2s, transform 0.2s var(--ease);
}
.btn:hover { transform: translate(-2px, -2px); box-shadow: 4px 4px 0 var(--ink); }
.btn.ghost { background: transparent; color: var(--ink); }
.btn.ghost:hover { background: var(--ink); color: var(--paper); }

/* ---------------- colour blocks ---------------- */
.block {
  position: relative; background: var(--c); color: #FFF6E8;
  border-bottom: 2px solid var(--ink); overflow: hidden;
}
.block-inner {
  display: grid; grid-template-columns: 1.15fr 0.85fr; gap: clamp(2rem, 5vw, 5rem);
  align-items: center; padding-block: clamp(3.5rem, 8vw, 7rem);
}
.block:nth-of-type(even) .block-inner { grid-template-columns: 0.85fr 1.15fr; }
.block:nth-of-type(even) .block-text { order: 2; }
.block:nth-of-type(even) .block-art { order: 1; }

.block-num {
  font-family: var(--display); font-weight: 900; font-size: clamp(3rem, 6vw, 5.5rem);
  line-height: 0.8; opacity: 0.45;
}
.block .label { opacity: 0.75; margin-top: 0.75rem; }
.block h2 {
  font-size: clamp(2.6rem, 6.5vw, 5.5rem); margin-top: 1.25rem; letter-spacing: -0.04em;
}
.block p { font-size: clamp(1rem, 1.5vw, 1.2rem); margin-top: 1.5rem; max-width: 38ch; opacity: 0.9; }
.block .go {
  display: inline-flex; align-items: center; gap: 0.7rem; margin-top: 2.25rem;
  font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.16em; text-transform: uppercase;
  padding-bottom: 0.4rem; border-bottom: 2px solid currentColor;
  transition: gap 0.3s var(--ease);
}
.block .go:hover { gap: 1.3rem; }
.block .tag {
  display: inline-block; font-family: var(--mono); font-size: 0.6rem; letter-spacing: 0.18em;
  text-transform: uppercase; border: 2px solid currentColor; padding: 4px 10px;
  margin-left: 1rem; vertical-align: middle;
}

/* diagram */
.diagram { width: 100%; max-width: 380px; margin-inline: auto; }
.diagram svg { width: 100%; height: auto; overflow: visible; }
.diagram figcaption {
  font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.16em; text-transform: uppercase;
  text-align: center; margin-top: 1.25rem; opacity: 0.55;
}

/* ---------------- article pages ---------------- */
.article-head { background: var(--c); color: #FFF6E8; border-bottom: 2px solid var(--ink); padding-block: clamp(3rem, 7vw, 5.5rem); }
.article-head .kicker { display: flex; align-items: center; gap: 1rem; opacity: 0.8; }
.article-head h1 { font-size: clamp(2.8rem, 8vw, 6rem); margin-top: 1.5rem; max-width: 15ch; letter-spacing: -0.04em; }
.article-head .summary { font-size: clamp(1.1rem, 2vw, 1.4rem); margin-top: 1.5rem; max-width: 44ch; opacity: 0.92; font-family: var(--display); font-weight: 700; font-variation-settings: "opsz" 40, "SOFT" 20, "WONK" 0; line-height: 1.3; }
.byline {
  font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.14em; text-transform: uppercase;
  margin-top: 2.5rem; padding-top: 1.25rem; border-top: 1px solid currentColor;
  display: flex; flex-wrap: wrap; gap: 0.5rem 2rem; opacity: 0.8;
}
.article-head .diagram { max-width: 240px; margin: 2.5rem auto 0; }
.article-head-grid { display: grid; grid-template-columns: 1.3fr 0.7fr; gap: 3rem; align-items: center; }

.article { padding-block: clamp(3rem, 6vw, 5rem); }
.prose { max-width: var(--measure); }
.prose p { margin-top: 1.4rem; }
.prose > p:first-of-type { margin-top: 0; font-size: 1.25rem; line-height: 1.55; color: var(--ink); }
.prose h2 {
  font-size: clamp(1.9rem, 4vw, 2.9rem); margin-top: 3.5rem; padding-top: 1.75rem;
  border-top: 2px solid var(--ink);
}
.prose h3 { font-family: var(--sans); font-weight: 600; font-size: 1.15rem; margin-top: 2.25rem; letter-spacing: 0; }
.prose a { color: var(--c); text-decoration: underline; text-underline-offset: 3px; text-decoration-thickness: 2px; }

.pullquote {
  font-family: var(--display); font-weight: 900; font-size: clamp(1.9rem, 4.5vw, 3.2rem);
  line-height: 1.02; letter-spacing: -0.03em; color: var(--c);
  margin: 3.5rem 0; max-width: 22ch;
}

.callout { background: var(--paper-2); border: 2px solid var(--ink); padding: 2rem; margin: 3.5rem 0; }
.callout .label { color: var(--c); margin-bottom: 1.25rem; display: block; }
.callout ul { list-style: none; display: grid; gap: 1rem; }
.callout li { position: relative; padding-left: 1.9rem; }
.callout li::before { content: ""; position: absolute; left: 0; top: 0.62em; width: 12px; height: 2px; background: var(--c); }

.refs { border-top: 2px solid var(--ink); padding-top: 2.25rem; margin-top: 3.5rem; }
.refs .label { margin-bottom: 1.25rem; display: block; color: var(--c); }
.refs ol { list-style: none; counter-reset: r; display: grid; gap: 1rem; margin-bottom: 2.25rem; }
.refs ol:last-child { margin-bottom: 0; }
.refs li { counter-increment: r; position: relative; padding-left: 2.6rem; color: var(--muted); font-size: 0.9rem; }
.refs li::before {
  content: counter(r); position: absolute; left: 0; top: 0; font-family: var(--mono);
  font-size: 0.68rem; color: var(--c); border: 2px solid var(--c); width: 1.9rem;
  text-align: center; line-height: 1.5rem;
}
.refs a { color: var(--c); text-decoration: underline; text-underline-offset: 3px; }

.compare { width: 100%; border-collapse: collapse; margin: 2.5rem 0 0; font-size: 0.92rem; }
.compare th, .compare td { text-align: left; padding: 1rem 0.9rem; border-bottom: 1px solid var(--rule); vertical-align: top; }
.compare th { font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--muted); font-weight: 500; border-bottom: 2px solid var(--ink); }
.compare td:first-child { font-weight: 600; color: var(--c); white-space: nowrap; }

/* ---------------- about ---------------- */
.about { padding-block: clamp(3.5rem, 8vw, 6rem); }
.about-grid { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(2rem, 5vw, 5rem); align-items: start; }
.about h2 { font-size: clamp(2.2rem, 5vw, 3.8rem); margin-bottom: 2.5rem; }
.about p { color: var(--ink-2); margin-top: 1.3rem; }
.about p:first-child { margin-top: 0; }
.contact-card { border: 2px solid var(--ink); padding: 2rem; background: var(--paper-2); }
.contact-card .label { color: var(--muted); }
.contact-card .big { font-family: var(--display); font-weight: 900; font-size: clamp(1.5rem, 3vw, 2.2rem); margin-top: 0.75rem; letter-spacing: -0.03em; word-break: break-word; }
.contact-card p { font-size: 0.94rem; margin-top: 1.25rem; color: var(--muted); }

/* ---------------- footer ---------------- */
.footer { background: var(--ink); color: var(--paper); padding-block: clamp(3rem, 6vw, 4.5rem); }
.footer h2 { font-size: clamp(2rem, 5vw, 3.6rem); max-width: 16ch; }
.footer .sub { color: var(--paper); opacity: 0.7; margin-top: 1.25rem; max-width: 46ch; }
.footer-meta {
  display: flex; justify-content: space-between; flex-wrap: wrap; gap: 1rem;
  margin-top: 3rem; padding-top: 1.5rem; border-top: 1px solid rgba(247,243,234,0.25);
  font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.08em; opacity: 0.8;
}
.footer-meta a:hover { text-decoration: underline; }
.disclaimer { font-family: var(--mono); font-size: 0.68rem; opacity: 0.55; max-width: 60ch; margin-top: 0.9rem; line-height: 1.7; }

/* ---------------- reveal ---------------- */
.reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.7s var(--ease), transform 0.7s var(--ease); }
.reveal.in { opacity: 1; transform: none; }

/* ---------------- responsive ---------------- */
@media (min-width: 1200px) {
  :root {
    --measure: 70ch;
    --pad: clamp(3.5rem, 5vw, 6.5rem);
  }

  body { font-size: 1.1rem; }

  .nav-inner { height: 76px; }
  .wordmark { font-size: 1.42rem; }
  .nav-links { gap: clamp(2rem, 3vw, 3.5rem); }
  .nav-links a { font-size: 0.76rem; }

  .masthead {
    padding-block: clamp(4.5rem, 6vw, 7rem) clamp(4rem, 5.5vw, 6.5rem);
  }
  .masthead .wrap {
    display: grid;
    grid-template-columns: minmax(0, 1.35fr) minmax(22rem, 0.65fr);
    column-gap: clamp(4rem, 8vw, 10rem);
    align-items: end;
  }
  .masthead-meta { grid-column: 1 / -1; }
  .masthead h1 {
    grid-column: 1;
    grid-row: 2 / span 3;
    align-self: center;
    font-size: clamp(7rem, 9.25vw, 11rem);
    max-width: 10ch;
    margin-top: clamp(3rem, 5vw, 5rem);
  }
  .masthead .standfirst {
    grid-column: 2;
    grid-row: 2;
    font-size: clamp(1.55rem, 1.65vw, 2rem);
    max-width: 28ch;
    margin-top: clamp(3rem, 5vw, 5rem);
  }
  .masthead .deck {
    grid-column: 2;
    grid-row: 3;
    max-width: 44ch;
    font-size: 1.08rem;
    margin-top: 1.6rem;
  }
  .masthead .actions {
    grid-column: 2;
    grid-row: 4;
    margin-top: 2.25rem;
  }

  .block-inner {
    grid-template-columns: minmax(0, 1.08fr) minmax(25rem, 0.92fr);
    gap: clamp(5rem, 8vw, 10rem);
    min-height: clamp(590px, 67vh, 760px);
    padding-block: clamp(5rem, 7vw, 8rem);
  }
  .block:nth-of-type(even) .block-inner {
    grid-template-columns: minmax(25rem, 0.92fr) minmax(0, 1.08fr);
  }
  .block h2 { font-size: clamp(4.6rem, 5.1vw, 6.6rem); max-width: 12ch; }
  .block p { font-size: clamp(1.16rem, 1.15vw, 1.35rem); max-width: 42ch; }
  .block .go { font-size: 0.8rem; margin-top: 2.75rem; }
  .block-num { font-size: clamp(4.5rem, 5vw, 6.5rem); }
  .diagram { max-width: clamp(440px, 29vw, 590px); }

  .article-head {
    padding-block: clamp(5rem, 7vw, 8rem);
  }
  .article-head-grid {
    grid-template-columns: minmax(0, 1.25fr) minmax(20rem, 0.75fr);
    gap: clamp(5rem, 8vw, 10rem);
  }
  .article-head h1 { font-size: clamp(5.5rem, 6.3vw, 7.5rem); }
  .article-head .summary { font-size: clamp(1.35rem, 1.45vw, 1.7rem); }
  .article-head .diagram { max-width: clamp(300px, 22vw, 410px); }
  .article { padding-block: clamp(5rem, 6vw, 7rem); }
  .article-grid {
    grid-template-columns: minmax(0, var(--measure)) minmax(17rem, 20rem);
    justify-content: space-between;
    gap: clamp(5rem, 8vw, 10rem);
  }
  .toc { top: 108px; }

  .about { padding-block: clamp(6rem, 8vw, 9rem); }
  .about-grid { gap: clamp(5rem, 8vw, 10rem); }
  .about h2 { font-size: clamp(4rem, 4.2vw, 5.5rem); }
  .footer { padding-block: clamp(5rem, 6vw, 7rem); }
}

@media (max-width: 900px) {
  .block-inner, .block:nth-of-type(even) .block-inner { grid-template-columns: 1fr; gap: 2.5rem; }
  .block:nth-of-type(even) .block-text { order: 1; }
  .block:nth-of-type(even) .block-art { order: 2; }
  .article-head-grid { grid-template-columns: 1fr; gap: 2rem; }
  .about-grid { grid-template-columns: 1fr; }
  .diagram { max-width: 300px; }
}
@media (max-width: 760px) {
  .nav-links {
    position: fixed; inset: 68px 0 auto 0; flex-direction: column; align-items: flex-start; gap: 0;
    background: var(--paper); border-bottom: 2px solid var(--ink); padding: 0.5rem var(--pad) 1.5rem;
    transform: translateY(-130%); visibility: hidden; pointer-events: none;
    transition: transform 0.4s var(--ease), visibility 0s linear 0.4s;
  }
  .nav-links.open {
    transform: none; visibility: visible; pointer-events: auto;
    transition: transform 0.4s var(--ease), visibility 0s linear 0s;
  }
  .nav-links a { width: 100%; padding: 1rem 0; border-bottom: 1px solid var(--rule); font-size: 0.85rem; }
  .menu-btn { display: inline-flex; }
  .compare, .compare tbody, .compare tr, .compare td { display: block; width: 100%; }
  .compare thead { display: none; }
  .compare tr { border-bottom: 2px solid var(--ink); padding: 1rem 0; }
  .compare td { border: 0; padding: 0.25rem 0; }
  .compare td:first-child { font-size: 1.1rem; margin-bottom: 0.4rem; }
}

/* ============================================================
   NAV MENUS, SETTINGS, BACK BUTTON
   ============================================================ */

.nav-inner { position: relative; }
.has-menu { position: relative; }
.menu-trigger {
  font-family: var(--mono); font-size: 0.72rem; letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--ink); background: none; border: 0; cursor: pointer; padding: 4px 0;
  display: inline-flex; align-items: center; gap: 0.45rem; position: relative;
}
.menu-trigger::after {
  content: ""; position: absolute; left: 0; right: 100%; bottom: 0; height: 2px;
  background: var(--ink); transition: right 0.35s var(--ease);
}
.menu-trigger:hover::after, .menu-trigger[aria-expanded="true"]::after { right: 0; }
.menu-trigger .chev { transition: transform 0.3s var(--ease); }
.menu-trigger[aria-expanded="true"] .chev { transform: rotate(180deg); }

.dropdown {
  position: absolute; top: calc(100% + 14px); right: 0; z-index: 120;
  background: var(--paper); border: 2px solid var(--ink); min-width: 300px;
  opacity: 0; visibility: hidden; transform: translateY(-8px);
  /* visibility flips instantly on open so menu items can take focus,
     and is delayed on close so the fade out is still seen */
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0s linear 0.25s;
  box-shadow: 6px 6px 0 var(--ink);
}
.dropdown[data-open="true"] {
  opacity: 1; visibility: visible; transform: none;
  transition: opacity 0.25s var(--ease), transform 0.25s var(--ease), visibility 0s linear 0s;
}
.dropdown .dd-head {
  font-family: var(--mono); font-size: 0.64rem; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--muted); padding: 0.9rem 1.1rem 0.6rem; border-bottom: 1px solid var(--rule);
}
.dropdown a.dd-item {
  display: flex; align-items: center; gap: 0.85rem; padding: 0.75rem 1.1rem;
  border-bottom: 1px solid var(--rule); transition: background 0.15s;
}
.dropdown a.dd-item:last-child { border-bottom: 0; }
.dropdown a.dd-item:hover { background: var(--paper-2); }
.dropdown a.dd-item .swatch { width: 14px; height: 14px; background: var(--c); flex: none; }
.dropdown a.dd-item .nm { font-size: 0.92rem; font-weight: 500; }
.dropdown a.dd-item .no {
  font-family: var(--mono); font-size: 0.66rem; color: var(--muted); margin-left: auto;
}

/* settings panel */
.settings-panel { min-width: 280px; padding: 0.35rem 0 0.75rem; }
.set-row { padding: 0.9rem 1.1rem; border-bottom: 1px solid var(--rule); }
.set-row:last-child { border-bottom: 0; }
.set-row > .lb {
  font-family: var(--mono); font-size: 0.64rem; letter-spacing: 0.18em; text-transform: uppercase;
  color: var(--muted); display: block; margin-bottom: 0.6rem;
}
.seg { display: flex; border: 2px solid var(--ink); }
.seg button {
  flex: 1; font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.08em; text-transform: uppercase;
  padding: 0.55rem 0.3rem; background: transparent; color: var(--ink); border: 0; cursor: pointer;
  border-right: 1px solid var(--ink); transition: background 0.15s, color 0.15s;
}
.seg button:last-child { border-right: 0; }
.seg button[aria-pressed="true"] { background: var(--ink); color: var(--paper); }
.set-toggle { display: flex; align-items: center; justify-content: space-between; gap: 1rem; }
.set-toggle .nm { font-size: 0.9rem; }
.switch {
  width: 46px; height: 26px; border: 2px solid var(--ink); background: transparent;
  cursor: pointer; position: relative; flex: none; padding: 0;
}
.switch::after {
  content: ""; position: absolute; top: 2px; left: 2px; width: 18px; height: 18px;
  background: var(--ink); transition: transform 0.22s var(--ease);
}
.switch[aria-pressed="true"] { background: var(--ink); }
.switch[aria-pressed="true"]::after { transform: translateX(20px); background: var(--paper); }

/* text-size scale */
html[data-size="s"]  { font-size: 93.75%; }
html[data-size="l"]  { font-size: 112.5%; }
html[data-motion="off"] *, html[data-motion="off"] *::before, html[data-motion="off"] *::after {
  animation: none !important; transition: none !important;
}
html[data-motion="off"] { scroll-behavior: auto; }

/* back button */
.backbar { border-bottom: 2px solid var(--ink); background: var(--paper); }
.backbar .wrap { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding-block: 0.85rem; }
.back-btn {
  display: inline-flex; align-items: center; gap: 0.65rem; font-family: var(--mono);
  font-size: 0.72rem; letter-spacing: 0.14em; text-transform: uppercase;
  border: 2px solid var(--ink); padding: 0.6rem 1.1rem; background: var(--paper); color: var(--ink);
  transition: background 0.18s, color 0.18s, transform 0.18s var(--ease);
}
.back-btn:hover { background: var(--ink); color: var(--paper); transform: translateX(-3px); }
.backbar .where { font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.16em; text-transform: uppercase; color: var(--muted); }

@media (max-width: 760px) {
  .dropdown { position: fixed; left: 0; right: 0; top: 68px; min-width: 0; border-left: 0; border-right: 0; box-shadow: none; }
  .backbar .where { display: none; }
}

/* extra colour tokens for the new interactives */
:root { --c-exposure: #A95C20; --c-resistance: #187E62; }
[data-theme="dark"] { --c-exposure: #C88A5A; --c-resistance: #3FBE9B; }

html[data-underline="on"] .prose a,
html[data-underline="on"] .block .go,
html[data-underline="on"] .dd-item .nm { text-decoration: underline; text-underline-offset: 3px; }




/* illustration set: every mark is currentColor, so each takes the cream of its block */
.diagram svg { width: 100%; height: auto; display: block; overflow: visible; }
.diagram svg [stroke-linecap] { stroke-linecap: round; }


/* ============================================================
   READER CONTROLS, TABLE OF CONTENTS, CITATIONS, GLOSSARY
   ============================================================ */

/* --- skip link --- */
.skip {
  position: absolute; left: -9999px; top: 0; z-index: 300;
  background: var(--ink); color: var(--paper); padding: 0.9rem 1.4rem;
  font-family: var(--mono); font-size: 0.74rem; letter-spacing: 0.14em; text-transform: uppercase;
}
.skip:focus { left: 0; }

/* --- visible keyboard focus everywhere --- */
:focus-visible {
  outline: 3px solid var(--ink); outline-offset: 2px; border-radius: 2px;
}
.block :focus-visible, .article-head :focus-visible, .footer :focus-visible {
  outline-color: currentColor;
}
[data-theme="dark"] :focus-visible { outline-color: var(--ink); }

/* --- reading progress --- */
.progress-rail {
  position: fixed; top: 0; left: 0; right: 0; height: 3px; z-index: 150;
  background: transparent; pointer-events: none;
}
.progress-rail span {
  display: block; height: 100%; width: 0%; background: var(--c, var(--ink));
  transition: width 0.08s linear;
}
html[data-motion="off"] .progress-rail span { transition: none; }

/* --- reader preference controls --- */
.set-row .hint {
  font-family: var(--mono); font-size: 0.58rem; letter-spacing: 0.1em;
  color: var(--faint); margin-top: 0.5rem; display: block; text-transform: none;
}
.settings-panel { max-height: min(78vh, 640px); overflow-y: auto; }
.set-group-label {
  font-family: var(--mono); font-size: 0.58rem; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--faint); padding: 0.9rem 1.1rem 0.3rem; border-top: 2px solid var(--ink);
  background: var(--paper-2);
}
.set-reset {
  width: 100%; text-align: left; padding: 0.85rem 1.1rem; background: none; border: 0;
  border-top: 1px solid var(--rule); cursor: pointer; color: var(--ink);
  font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.12em; text-transform: uppercase;
}
.set-reset:hover { background: var(--paper-2); }

/* reading width */
html[data-width="narrow"]  { --measure: 54ch; }
html[data-width="wide"]    { --measure: 82ch; }
/* line spacing */
html[data-leading="tight"] .prose p, html[data-leading="tight"] .prose li { line-height: 1.45; }
html[data-leading="loose"] .prose p, html[data-leading="loose"] .prose li { line-height: 1.95; }
/* article typeface */
html[data-font="serif"] .prose { font-family: var(--display); font-variation-settings: "opsz" 14, "SOFT" 0, "WONK" 0; }
html[data-font="serif"] .prose p { font-weight: 400; }
html[data-font="mono"] .prose { font-family: var(--mono); font-size: 0.94em; }

/* higher contrast */
html[data-contrast="high"] {
  --muted: var(--ink); --faint: var(--ink-2); --rule: var(--ink); --rule-2: var(--ink);
}
html[data-contrast="high"] .prose p { opacity: 1; }
html[data-contrast="high"] .diagram figcaption { opacity: 1; }
html[data-contrast="high"] .block p,
html[data-contrast="high"] .article-head .summary { opacity: 1; }
html[data-contrast="high"] .prose a { text-decoration-thickness: 3px; }
html[data-contrast="high"] .refs li { color: var(--ink); }

/* --- article layout with a sticky contents rail --- */
.article-grid { display: grid; grid-template-columns: minmax(0,1fr) 15rem; gap: clamp(2rem,5vw,4.5rem); align-items: start; }
.toc { position: sticky; top: 92px; font-family: var(--mono); }
.toc h2 {
  font-family: var(--mono); font-size: 0.62rem; letter-spacing: 0.2em; text-transform: uppercase;
  color: var(--faint); font-weight: 500; margin-bottom: 0.9rem; padding-bottom: 0.6rem;
  border-bottom: 2px solid var(--ink); letter-spacing: 0.2em;
}
.toc ol { list-style: none; display: grid; gap: 0.15rem; }
.toc a {
  display: block; padding: 0.45rem 0 0.45rem 0.85rem; font-size: 0.74rem; line-height: 1.4;
  color: var(--muted); border-left: 2px solid var(--rule); transition: color 0.2s, border-color 0.2s;
}
.toc a:hover { color: var(--ink); border-color: var(--ink); }
.toc a[aria-current="true"] { color: var(--c); border-color: var(--c); font-weight: 500; }
.toc .toc-read {
  margin-top: 1rem; padding-top: 0.8rem; border-top: 1px solid var(--rule);
  font-size: 0.62rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--faint);
}
.toc-toggle { display: none; }

/* --- heading anchors --- */
.prose h2 { position: relative; scroll-margin-top: 92px; }
.prose h2 .anchor {
  position: absolute; left: -1.6rem; top: 50%; transform: translateY(-40%);
  font-family: var(--mono); font-size: 0.9rem; color: var(--c); opacity: 0;
  transition: opacity 0.2s; text-decoration: none;
}
.prose h2:hover .anchor, .prose h2 .anchor:focus-visible { opacity: 0.7; }

/* --- inline citations --- */
a.cite {
  font-family: var(--mono); font-size: 0.62em; font-weight: 600; vertical-align: super;
  line-height: 0; color: var(--c); text-decoration: none; padding: 0 0.12em;
  border-bottom: 0; white-space: nowrap;
}
a.cite:hover, a.cite:focus-visible { text-decoration: underline; text-underline-offset: 2px; }
.refs li:target { background: var(--c); color: var(--paper); padding: 0.4rem 0.6rem; margin-left: -0.6rem; }
.refs li:target::before { border-color: var(--paper); color: var(--paper); }
.refs li { scroll-margin-top: 100px; }

/* --- evidence status labels --- */
.ev {
  display: inline-flex; align-items: center; gap: 0.35rem; vertical-align: baseline;
  font-family: var(--mono); font-size: 0.58rem; letter-spacing: 0.14em; text-transform: uppercase;
  padding: 0.18rem 0.5rem; border: 1.5px solid currentColor; white-space: nowrap;
  margin-left: 0.15rem;
}
.ev::before { content: ""; width: 6px; height: 6px; background: currentColor; flex: none; }
.ev-approved { color: #2C7A45; }
.ev-trials   { color: #A75B17; }
.ev-early    { color: #6B6357; }
[data-theme="dark"] .ev-approved { color: #63B96D; }
[data-theme="dark"] .ev-trials   { color: #E0964A; }
[data-theme="dark"] .ev-early    { color: #A79D8C; }
.ev-key {
  display: flex; flex-wrap: wrap; gap: 0.8rem 1.4rem; align-items: center;
  border: 2px solid var(--ink); background: var(--paper-2); padding: 0.9rem 1.1rem; margin-bottom: 2.5rem;
}
.ev-key .lb { font-family: var(--mono); font-size: 0.58rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--muted); }

/* --- glossary terms --- */
.gloss {
  border-bottom: 2px dotted var(--c); cursor: help; position: relative;
  background: none; border-top: 0; border-left: 0; border-right: 0; padding: 0;
  font: inherit; color: inherit; text-align: left;
}
.gloss:hover, .gloss:focus-visible { background: var(--paper-2); }
.gloss .def {
  position: absolute; left: 0; top: calc(100% + 0.5rem); z-index: 60; width: min(20rem, 78vw);
  background: var(--paper); border: 2px solid var(--ink); box-shadow: 5px 5px 0 var(--ink);
  padding: 0.9rem 1rem; font-family: var(--sans); font-size: 0.86rem; line-height: 1.55;
  color: var(--ink); opacity: 0; visibility: hidden; transform: translateY(-4px);
  transition: opacity 0.18s, transform 0.18s, visibility 0.18s; text-align: left; font-weight: 400;
}
.gloss[aria-expanded="true"] .def { opacity: 1; visibility: visible; transform: none; }
.gloss .def strong {
  display: block; font-family: var(--mono); font-size: 0.6rem; letter-spacing: 0.16em;
  text-transform: uppercase; color: var(--c); margin-bottom: 0.4rem;
}

/* --- previous / next --- */
.pager { margin-top: 3.5rem; display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.pager a {
  padding: 1.75rem 1.5rem; display: flex; flex-direction: column; gap: 0.4rem;
  transition: background 0.2s;
}
.pager a:hover { background: var(--paper-2); }
.pager a + a { text-align: right; align-items: flex-end; }
.pager .dir { font-family: var(--mono); font-size: 0.6rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--muted); }
.pager .ttl { font-family: var(--display); font-weight: 900; font-size: clamp(1.05rem,2vw,1.35rem); letter-spacing: -0.02em; line-height: 1.15; }
.pager .none { opacity: 0.35; pointer-events: none; }

/* --- back to top --- */
.to-top {
  position: fixed; right: clamp(1rem,3vw,2rem); bottom: clamp(1rem,3vw,2rem); z-index: 90;
  width: 46px; height: 46px; display: grid; place-items: center; cursor: pointer;
  background: var(--ink); color: var(--paper); border: 2px solid var(--ink);
  opacity: 0; visibility: hidden; transform: translateY(8px);
  transition: opacity 0.25s, transform 0.25s, visibility 0.25s;
}
.to-top.show { opacity: 1; visibility: visible; transform: none; }
.to-top svg { width: 18px; height: 18px; }

/* --- share / copy link --- */
.share { display: flex; gap: 0.6rem; align-items: center; margin-top: 1.5rem; flex-wrap: wrap; }
.share button {
  font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.12em; text-transform: uppercase;
  padding: 0.55rem 0.95rem; border: 2px solid currentColor; background: transparent;
  color: inherit; cursor: pointer; transition: background 0.18s, color 0.18s;
}
.share button:hover { background: currentColor; }
.share button:hover span { color: var(--c); }

/* --- current page in the section menu --- */
.dropdown a.dd-item[aria-current="page"] { background: var(--paper-2); }
.dropdown a.dd-item[aria-current="page"] .nm { font-weight: 600; }
.dropdown a.dd-item[aria-current="page"]::after {
  content: "Now reading"; font-family: var(--mono); font-size: 0.52rem; letter-spacing: 0.14em;
  text-transform: uppercase; color: var(--c); margin-left: auto; padding-left: 0.6rem;
}
.dropdown a.dd-item[aria-current="page"] .no { display: none; }

@media (max-width: 1080px) {
  .article-grid { grid-template-columns: 1fr; }
  .toc {
    position: static; border: 2px solid var(--ink); background: var(--paper-2);
    padding: 0 1rem; margin-bottom: 2.5rem;
  }
  .toc-toggle {
    display: flex; width: 100%; align-items: center; justify-content: space-between;
    background: none; border: 0; padding: 1rem 0; cursor: pointer; color: var(--ink);
    font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.18em; text-transform: uppercase;
  }
  .toc h2 { display: none; }
  .toc .toc-body { display: none; padding-bottom: 1rem; }
  .toc.open .toc-body { display: block; }
  .toc-toggle .chev { transition: transform 0.3s var(--ease); }
  .toc.open .toc-toggle .chev { transform: rotate(180deg); }
}
@media (max-width: 760px) {
  .pager { grid-template-columns: 1fr; }
  .pager a + a { text-align: left; align-items: flex-start; }
  .gloss .def { position: fixed; left: 4vw; right: 4vw; width: auto; top: auto; bottom: 1rem; }
}

/* --- print --- */
@media print {
  .nav, .backbar, .toc, .pager, .to-top, .progress-rail, .share, .footer, .skip { display: none !important; }
  body { background: #fff; color: #000; }
  .article-head { background: #fff !important; color: #000 !important; border-bottom: 2px solid #000; }
  .diagram { max-width: 150px; }
  .prose { max-width: none; }
  .prose a::after { content: " (" attr(href) ")"; font-size: 0.8em; word-break: break-all; }
  a.cite::after { content: none; }
}

/* --- previous / next, wearing the colour of where they go --- */
.pager a {
  background: var(--to); color: #FFF6E8; padding: 2rem 1.75rem;
  border: 2px solid var(--ink); position: relative; overflow: hidden;
  transition: filter 0.2s;
}
.pager a:only-child { grid-column: 1 / -1; }
.pager a:hover { background: var(--to); filter: brightness(1.12); }

.pager .dir { display: flex; align-items: center; gap: 0.5rem; opacity: 0.85; }
.pager a + a .dir { flex-direction: row-reverse; }
.pager .arw { font-size: 1rem; transition: transform 0.25s var(--ease); }
.pager a:hover .arw { transform: translateX(-5px); }
.pager a + a:hover .arw { transform: translateX(5px); }
.pager .ttl { margin-top: 0.5rem; }
.pager .kind {
  font-family: var(--mono); font-size: 0.58rem; letter-spacing: 0.18em;
  text-transform: uppercase; opacity: 0.7; margin-top: 0.6rem;
}

/* ============================================================
   SECTION MODELS
   ============================================================ */
.figure-box {
  border: 2px solid var(--ink); background: var(--paper-2);
  padding: clamp(1.25rem, 3vw, 1.9rem); margin: 3rem 0;
}
.fig-label {
  font-family: var(--mono); font-size: 0.6rem; letter-spacing: 0.22em;
  text-transform: uppercase; color: var(--c);
}
.fig-title {
  font-family: var(--display); font-weight: 900; font-size: clamp(1.2rem, 2.4vw, 1.65rem);
  letter-spacing: -0.02em; line-height: 1.12; margin: 0.6rem 0 1.4rem;
}
.fig-stage { border: 2px solid var(--ink); background: var(--paper); padding: 1.1rem; }
.fig-stage svg { width: 100%; height: auto; display: block; overflow: hidden; }
.fig-stage svg text { font-family: var(--mono); fill: var(--muted); }
.fig-stage svg .cap { font-size: 11px; letter-spacing: 0.06em; }
.fig-stage svg .mid { text-anchor: middle; }
.fig-stage svg .big {
  font-family: var(--display); font-weight: 900; font-size: 30px; fill: var(--c); letter-spacing: -0.02em;
}
.fig-stage svg .track { fill: var(--rule); }
.fig-stage svg .fill { fill: var(--c); }
.fig-stage svg .axis { stroke: var(--ink); stroke-width: 1.5; }
.fig-stage svg .scrub { stroke: var(--c); stroke-width: 2; }
.fig-stage svg .vessel { fill: none; stroke: var(--ink); stroke-width: 2.5; }
.fig-stage svg .wall { fill: var(--c); opacity: 0.18; stroke: none; }
.fig-stage svg .lumen { fill: var(--paper); stroke: var(--c); stroke-width: 2; transition: r 0.25s var(--ease); }
.fig-stage svg .tumour { fill: var(--c); opacity: 0.22; stroke: var(--c); stroke-width: 2.5; }
.fig-stage svg .tcell { stroke: var(--ink); stroke-width: 2; transition: cx 0.4s var(--ease), cy 0.4s var(--ease); }
.fig-stage svg .tcell.live { fill: var(--c); }
.fig-stage svg .tcell.off { fill: var(--rule); }
.fig-stage svg .curve { fill: none; stroke: var(--c); stroke-width: 3; }
.fig-stage svg .ill { fill: none; stroke: var(--muted); stroke-width: 2.2; stroke-dasharray: 6 5; }
.fig-stage svg rect.fill { transition: width 0.3s var(--ease), opacity 0.2s; }

.fig-ctrl { display: flex; flex-wrap: wrap; gap: 0.8rem 1.2rem; align-items: center; margin-top: 1.2rem; }
.fig-slider { flex: 1 1 15rem; }
.fig-slider label {
  display: block; font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.1em;
  text-transform: uppercase; color: var(--muted); margin-bottom: 0.5rem;
}
.fig-slider label b { color: var(--c); font-weight: 500; }
.fig-slider input[type=range] {
  width: 100%; -webkit-appearance: none; appearance: none; height: 4px; background: var(--rule-2); outline: none;
}
.fig-slider input[type=range]::-webkit-slider-thumb {
  -webkit-appearance: none; width: 20px; height: 20px; background: var(--c);
  border: 2px solid var(--ink); cursor: pointer;
}
.fig-slider input[type=range]::-moz-range-thumb {
  width: 18px; height: 18px; background: var(--c); border: 2px solid var(--ink);
  cursor: pointer; border-radius: 0;
}
.fig-choices { display: flex; flex-wrap: wrap; border: 2px solid var(--ink); }
.fig-choices button {
  font-family: var(--mono); font-size: 0.64rem; letter-spacing: 0.08em; text-transform: uppercase;
  padding: 0.5rem 0.8rem; background: transparent; color: var(--ink); border: 0;
  border-right: 1px solid var(--ink); cursor: pointer;
}
.fig-choices button:last-child { border-right: 0; }
.fig-choices button[aria-pressed="true"] { background: var(--c); color: #FFF6E8; }
.fig-step, .fig-check {
  font-family: var(--mono); font-size: 0.64rem; letter-spacing: 0.08em; text-transform: uppercase;
  display: inline-flex; align-items: center; gap: 0.45rem; cursor: pointer; color: var(--ink);
}
.fig-step { border: 2px solid var(--ink); background: transparent; padding: 0.5rem 0.9rem; }
.fig-step:hover { background: var(--ink); color: var(--paper); }
.fig-check input { width: 15px; height: 15px; accent-color: var(--c); }
.fig-out { font-size: 0.9rem; color: var(--ink-2); margin-top: 1.1rem; line-height: 1.6; }
.fig-grid { display: grid; grid-template-columns: repeat(8, 1fr); gap: 5px; }
.fig-grid .gcell {
  aspect-ratio: 1; background: var(--rule); border-radius: 50%;
  transition: background 0.3s var(--ease);
}
.fig-grid .gcell.r { background: var(--c); }
@media (max-width: 620px) { .fig-ctrl { gap: 0.9rem; } .fig-slider { flex: 1 1 100%; } }
@media print { .figure-box { break-inside: avoid; } }

/* --- article extras that can be switched off --- */
html[data-gloss="off"] .gloss { border-bottom-color: transparent; }
html[data-evidence="off"] .prose .ev, html[data-evidence="off"] .ev-key { display: none; }

/* --- resume prompt --- */
.resume {
  position: fixed; left: 50%; transform: translateX(-50%) translateY(120%); bottom: 1.25rem; z-index: 120;
  display: flex; align-items: center; gap: 1rem; flex-wrap: wrap;
  background: var(--ink); color: var(--paper); border: 2px solid var(--ink);
  padding: 0.85rem 1.1rem; font-family: var(--mono); font-size: 0.7rem; letter-spacing: 0.08em;
  transition: transform 0.35s var(--ease); max-width: calc(100vw - 2rem);
}
.resume.show { transform: translateX(-50%) translateY(0); }
.resume button {
  font: inherit; text-transform: uppercase; letter-spacing: 0.12em; cursor: pointer;
  border: 2px solid var(--paper); background: transparent; color: var(--paper); padding: 0.35rem 0.7rem;
}
.resume button:hover { background: var(--paper); color: var(--ink); }
.resume .dismiss { border-color: transparent; opacity: 0.7; }

/* --- read ticks in the contents menu --- */
.dd-item .tick {
  font-family: var(--mono); font-size: 0.62rem; color: var(--c); margin-left: auto;
  padding-left: 0.6rem; opacity: 0; transition: opacity 0.2s;
}
.dd-item.read .tick { opacity: 1; }
.dd-item.read .no { display: none; }

/* --- extra pieces used by the rebuilt models --- */
.fig-stage svg .gapfill { fill: var(--c); opacity: 0.15; }
.fig-stage svg .sick { fill: var(--muted); opacity: 0.55; }
.fig-organs { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0.6rem; }
.organ {
  display: flex; flex-direction: column; gap: 0.28rem; text-align: left; cursor: pointer;
  border: 2px solid var(--rule-2); background: var(--paper); padding: 0.7rem 0.75rem;
  font-family: var(--mono); color: var(--ink); transition: border-color 0.2s, background 0.2s;
}
.organ .on { font-size: 0.76rem; font-weight: 600; letter-spacing: 0.04em; }
.organ .st { font-size: 0.6rem; letter-spacing: 0.12em; text-transform: uppercase; color: var(--muted); }
.organ .act { font-size: 0.56rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--c); margin-top: 0.2rem; }
.organ.failing { border-color: var(--c); background: color-mix(in srgb, var(--c) 10%, var(--paper)); }
.organ.supported { border-color: var(--ink); }
.organ.supported .st { color: var(--ink); }
.organ:disabled { opacity: 0.45; cursor: default; }
.fig-meter { height: 14px; background: var(--rule); margin-top: 0.9rem; border: 2px solid var(--ink); }
.fig-meter span { display: block; height: 100%; background: var(--c); transition: width 0.3s var(--ease); }
.fig-meter.low span { background: var(--muted); }
.fig-clock { font-family: var(--mono); font-size: 0.66rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--muted); margin-top: 0.6rem; }
.fig-step:disabled { opacity: 0.4; cursor: default; }
@media (max-width: 560px) { .fig-organs { grid-template-columns: 1fr; } }