/* ============================================================
   NEW AI HEALTH
   EXPLAINER FAMILY

   Depends on:
   /themes/css/system.css
   /themes/css/styles.css

   Owns:
   - Health AI Definitions index
   - explainer topic pages
   - topic navigation
   - related terms
   - educational boundaries
   - visual explainer surfaces
   - native dialog lightboxes

   Does not own:
   - global reset or tokens
   - shared header or menu
   - shared footer
   - article publication layouts
   - institutional standards pages
   ============================================================ */


/* ============================================================
   EXPLAINER INDEX
   ============================================================ */

.explainer-index {
  width: 100%;
  margin-inline: auto;
  padding:
    clamp(var(--space-16), 8vw, var(--space-24))
    0
    clamp(var(--space-20), 9vw, 7rem);
}

.explainer-index-header {
  max-width: 850px;
  margin: 0 0 var(--space-10);
}

.explainer-index-eyebrow {
  margin: 0 0 var(--space-4);

  color: var(--red);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-semibold);
  letter-spacing: 0.12em;
  line-height: 1.35;
  text-transform: uppercase;
}

.explainer-index-header h1 {
  max-width: 13ch;
  margin: 0;

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: var(--text-display-sm);
  font-weight: 680;
  letter-spacing: var(--tracking-hero);
  line-height: 0.98;
  text-wrap: balance;
}

.explainer-index-subtitle {
  max-width: 760px;
  margin: var(--space-5) 0 0;

  color: var(--text-soft);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  letter-spacing: 0.012em;
  line-height: 1.65;
}

.explainer-index-lede {
  max-width: 680px;
  margin: var(--space-6) 0 0;

  color: var(--text);
  font-size: var(--text-lg);
  line-height: 1.72;
}


/* ============================================================
   EDUCATIONAL BOUNDARY
   ============================================================ */

.explainer-boundary {
  max-width: var(--reading-width);
  margin: var(--space-8) 0 0;
  padding: var(--space-5) var(--space-6);

  border: 1px solid var(--border);
  border-radius: var(--radius-card);

  background: var(--peach);
}

.explainer-boundary p {
  margin: 0;

  color: var(--text-soft);
  font-size: var(--text-sm);
  line-height: 1.68;
}


/* ============================================================
   EXPLAINER GROUPS
   ============================================================ */

.explainer-groups {
  margin-top: var(--space-16);
  padding-top: var(--space-10);

  border-top: 1px solid var(--divider);
}

.explainer-groups-header {
  max-width: var(--reading-width);
  margin-bottom: var(--space-6);
}

.explainer-groups h2,
.explainer-directory-header h2 {
  margin: 0;

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: clamp(1.65rem, 3vw, 2.25rem);
  font-weight: 660;
  letter-spacing: var(--tracking-display);
  line-height: 1.08;
  text-wrap: balance;
}

.explainer-groups-header p,
.explainer-directory-header p {
  max-width: 680px;
  margin: var(--space-4) 0 0;

  color: var(--text-soft);
  font-size: var(--text-base);
  line-height: 1.7;
}

.explainer-group-grid {
  display: grid;
  grid-template-columns:
    repeat(
      auto-fit,
      minmax(min(100%, 13.5rem), 1fr)
    );
  gap: var(--grid-gap);
}

.explainer-group-card {
  min-width: 0;
  padding: var(--space-6);

  border: 1px solid var(--border);
  border-radius: var(--radius-card);

  background: var(--surface-soft);
}

.explainer-group-card h3 {
  margin: 0;

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 640;
  letter-spacing: var(--tracking-tight);
  line-height: 1.15;
}

.explainer-group-card p {
  margin: var(--space-4) 0 0;

  color: var(--text-soft);
  font-size: var(--text-sm);
  line-height: 1.68;
}


/* ============================================================
   EXPLAINER DIRECTORY
   ============================================================ */

.explainer-directory-section {
  margin-top: var(--space-16);
  padding-top: var(--space-10);

  border-top: 1px solid var(--divider);
}

.explainer-directory-header {
  max-width: var(--reading-width);
  margin-bottom: var(--space-6);
}

.explainer-directory {
  display: grid;
  grid-template-columns:
    repeat(
      auto-fit,
      minmax(min(100%, 16.5rem), 1fr)
    );
  gap: var(--grid-gap);
}

.explainer-card {
  position: relative;

  min-width: 0;
  min-height: 100%;
  padding: var(--space-6);

  display: flex;
  flex-direction: column;

  border: 1px solid var(--border);
  border-radius: var(--radius-card);

  background: var(--surface);

  box-shadow: var(--shadow-soft);

  color: inherit;
  text-decoration: none;

  transition:
    transform var(--duration-standard) var(--ease-out),
    border-color var(--duration-standard) var(--ease-standard),
    background var(--duration-standard) var(--ease-standard),
    box-shadow var(--duration-standard) var(--ease-standard);
}

.explainer-card:hover {
  transform: translateY(-2px);

  border-color: var(--border-hover);

  background: var(--surface-hover);

  box-shadow: var(--shadow-card-hover);

  color: inherit;
}

.explainer-card:focus-visible {
  border-color: var(--blue);

  outline: none;

  box-shadow:
    var(--shadow-focus),
    var(--shadow-card-hover);
}

.explainer-card-category {
  display: block;
  margin: 0 0 var(--space-4);

  color: var(--text-faint);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-semibold);
  letter-spacing: 0.1em;
  line-height: 1.4;
  text-transform: uppercase;
}

.explainer-card h3 {
  margin: 0;

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: clamp(1.2rem, 2vw, 1.48rem);
  font-weight: 650;
  letter-spacing: var(--tracking-tight);
  line-height: 1.15;
  text-wrap: balance;
}

.explainer-card-description {
  margin: var(--space-4) 0 0;

  color: var(--text-soft);
  font-size: var(--text-sm);
  line-height: 1.68;
}

.explainer-card-cta {
  margin-top: auto;
  padding-top: var(--space-6);

  display: inline-flex;
  align-items: center;
  gap: var(--space-2);

  color: var(--blue);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-semibold);
  line-height: 1.4;
}

.explainer-card-cta::after {
  content: "\2192";

  color: var(--red);

  transition:
    transform var(--duration-standard) var(--ease-out);
}

.explainer-card:hover .explainer-card-cta::after,
.explainer-card:focus-visible .explainer-card-cta::after {
  transform: translateX(3px);
}


/* ============================================================
   EXPLAINER TOPIC PAGE
   ============================================================ */

.explainer-topic {
  width: min(100%, var(--reading-width));
  margin-inline: auto;
  padding:
    clamp(var(--space-12), 7vw, var(--space-20))
    0
    clamp(var(--space-20), 9vw, 7rem);
}

.explainer-topic-header {
  max-width: 740px;
  margin-top: var(--space-10);
}

.explainer-topic-eyebrow {
  margin: 0 0 var(--space-4);

  color: var(--red);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-semibold);
  letter-spacing: 0.12em;
  line-height: 1.35;
  text-transform: uppercase;
}

.explainer-topic-header h1 {
  max-width: 15ch;
  margin: 0;

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: var(--text-display-sm);
  font-weight: 680;
  letter-spacing: var(--tracking-hero);
  line-height: 0.98;
  text-wrap: balance;
}

.explainer-topic-deck {
  max-width: 700px;
  margin: var(--space-5) 0 0;

  color: var(--text);
  font-size: var(--text-lg);
  line-height: 1.7;
}

.explainer-topic-updated {
  margin: var(--space-4) 0 0;

  color: var(--text-faint);
  font-size: var(--text-sm);
  line-height: 1.5;
}

.explainer-topic-kicker {
  max-width: 620px;
  margin: var(--space-6) 0 0;

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: clamp(1.35rem, 2.1vw, 1.65rem);
  font-weight: 500;
  letter-spacing: -0.02em;
  line-height: 1.32;
  text-wrap: balance;
}


/* ============================================================
   TOPIC NAVIGATION
   ============================================================ */

.explainer-topic-nav {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: var(--space-6);
}

.explainer-topic-nav-link {
  min-width: 0;
  max-width: 46%;

  display: grid;
  gap: var(--space-1);

  color: inherit;
  text-decoration: none;
}

.explainer-topic-nav-link:last-child {
  justify-items: end;
  text-align: right;
}

.explainer-topic-nav-direction {
  color: var(--text-faint);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-semibold);
  letter-spacing: 0.08em;
  line-height: 1.35;
  text-transform: uppercase;
}

.explainer-topic-nav-name {
  color: var(--blue);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  line-height: 1.45;
  text-decoration: underline;
  text-decoration-color: rgba(47, 111, 159, 0.28);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;

  transition:
    color var(--duration-fast) var(--ease-standard),
    text-decoration-color var(--duration-fast) var(--ease-standard);
}

.explainer-topic-nav-link:hover .explainer-topic-nav-name {
  color: var(--text-strong);
  text-decoration-color: var(--red);
}

.explainer-topic-nav-link:focus-visible {
  border-radius: var(--radius-sm);

  outline: 2px solid var(--blue);
  outline-offset: 5px;
}

.explainer-topic-nav--bottom {
  margin-top: var(--space-12);
  padding-top: var(--space-8);

  border-top: 1px solid var(--divider);
}


/* ============================================================
   TOPIC READING FLOW
   ============================================================ */

.explainer-topic-body {
  margin-top: var(--space-16);
}

.explainer-topic-section {
  margin: 0;
}

.explainer-topic-section + .explainer-topic-section {
  margin-top: var(--space-12);
  padding-top: var(--space-10);

  border-top: 1px solid var(--divider);
}

.explainer-topic-section h2 {
  max-width: 24ch;
  margin: 0 0 var(--space-5);

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: clamp(1.5rem, 2.8vw, 2rem);
  font-weight: 650;
  letter-spacing: var(--tracking-display);
  line-height: 1.1;
  text-wrap: balance;
}

.explainer-topic-section p {
  max-width: 72ch;
  margin: 0;

  color: var(--text);
  font-size: var(--text-base);
  line-height: 1.78;
}

.explainer-topic-section p + p {
  margin-top: var(--space-5);
}

.explainer-topic-section a {
  color: var(--blue);
  font-weight: var(--font-weight-medium);
  text-decoration-color: rgba(47, 111, 159, 0.32);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;

  transition:
    color var(--duration-fast) var(--ease-standard),
    text-decoration-color var(--duration-fast) var(--ease-standard);
}

.explainer-topic-section a:hover {
  color: var(--text-strong);
  text-decoration-color: var(--red);
}

.explainer-topic-section a:focus-visible {
  border-radius: 3px;

  outline: 2px solid var(--blue);
  outline-offset: 3px;
}

.explainer-topic-section--emphasis {
  padding-left: var(--space-6);

  border-left: 3px solid var(--blue);
}

.explainer-topic-section--emphasis +
.explainer-topic-section {
  margin-top: var(--space-12);
}


/* ============================================================
   RELATED TERMS
   ============================================================ */

.explainer-related-terms {
  margin: 0;
  padding: 0;

  display: flex;
  flex-wrap: wrap;
  gap:
    var(--space-3)
    var(--space-5);

  list-style: none;
}

.explainer-related-terms li {
  margin: 0;
}

.explainer-related-terms a {
  display: inline-flex;

  color: var(--blue);
  font-size: var(--text-sm);
  font-weight: var(--font-weight-medium);
  line-height: 1.5;
}


/* ============================================================
   VISUAL EXPLAINER SURFACE
   ============================================================ */

.explainer-visual {
  width: min(100%, 640px);
  margin:
    clamp(var(--space-12), 7vw, var(--space-16))
    auto
    var(--space-16);
  padding: 26px;

  border: 1px solid var(--border);
  border-radius: 30px;

  background:
    linear-gradient(
      180deg,
      rgba(255, 255, 255, 0.88),
      rgba(255, 255, 255, 0.72)
    ),
    radial-gradient(
      circle at 18% 0%,
      rgba(255, 31, 31, 0.05),
      transparent 42%
    ),
    radial-gradient(
      circle at 86% 12%,
      rgba(47, 111, 159, 0.07),
      transparent 46%
    );

  box-shadow:
    0 22px 62px rgba(20, 27, 34, 0.075),
    0 1px 0 rgba(255, 255, 255, 0.88) inset;
}

.explainer-visual-copy {
  max-width: 520px;
  margin: 0 auto var(--space-5);

  text-align: center;
}

.explainer-visual-kicker {
  margin: 0 0 var(--space-2);

  color: var(--text-faint);
  font-size: var(--text-xs);
  font-weight: var(--font-weight-bold);
  letter-spacing: 0.12em;
  line-height: 1.2;
  text-transform: uppercase;
}

.explainer-visual-copy h2 {
  margin: 0;

  color: var(--text-strong);
  font-family: var(--font-display);
  font-size: clamp(1.24rem, 2vw, 1.6rem);
  font-weight: 650;
  letter-spacing: var(--tracking-display);
  line-height: 1.08;
  text-wrap: balance;
}

.explainer-visual-copy p {
  max-width: 500px;
  margin: var(--space-3) auto 0;

  color: var(--text-soft);
  font-size: var(--text-sm);
  line-height: 1.62;
}

.explainer-visual-frame {
  max-width: 440px;
  margin: 0 auto;
  padding: 12px;

  border: 1px solid var(--border);
  border-radius: 24px;

  background: var(--surface-frosted-strong);

  box-shadow:
    0 16px 42px rgba(20, 27, 34, 0.07),
    0 1px 0 rgba(255, 255, 255, 0.92) inset;
}

.explainer-visual-trigger {
  width: 100%;
  margin: 0;
  padding: 8px;

  display: flex;
  align-items: center;
  justify-content: center;

  border: 0;
  border-radius: 18px;

  background: var(--surface);

  cursor: zoom-in;

  overflow: visible;
}

.explainer-visual-trigger:hover {
  background: var(--surface-hover);
}

.explainer-visual-trigger:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 4px;

  box-shadow: var(--shadow-focus);
}

.explainer-visual-trigger img {
  display: block;

  width: auto;
  max-width: 100%;
  max-height: 300px;
  height: auto;

  border-radius: var(--radius-sm);

  background: var(--surface);
}

.explainer-visual-caption {
  margin: 10px 6px 2px;

  color: var(--text-faint);
  font-size: 0.74rem;
  line-height: 1.5;
  text-align: center;
}

.explainer-enlarge-cue {
  appearance: none;
  -webkit-appearance: none;

  margin: 0;
  padding: 0;

  display: inline;

  border: 0;

  background: transparent;

  color: var(--blue);
  font: inherit;
  font-weight: var(--font-weight-bold);
  line-height: inherit;
  letter-spacing: inherit;
  text-decoration: underline;
  text-decoration-color: rgba(47, 111, 159, 0.3);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;

  cursor: zoom-in;
}

.explainer-enlarge-cue:hover {
  color: var(--text-strong);
  text-decoration-color: var(--red);
}

.explainer-enlarge-cue:focus-visible {
  border-radius: 3px;

  outline: 2px solid var(--blue);
  outline-offset: 3px;
}


/* ============================================================
   NATIVE DIALOG LIGHTBOX
   ============================================================ */

.explainer-lightbox {
  position: relative;

  width: min(1120px, calc(100vw - 32px));
  max-height: calc(100vh - 32px);
  padding: 16px;

  border: 1px solid var(--border-strong);
  border-radius: 28px;

  background: var(--surface-frosted-strong);

  box-shadow:
    0 30px 90px rgba(20, 27, 34, 0.22);
}

.explainer-lightbox::backdrop {
  background: rgba(23, 33, 43, 0.52);

  backdrop-filter: blur(4px);
}

.explainer-lightbox figure {
  margin: 0;
}

.explainer-lightbox img {
  display: block;

  width: 100%;
  max-height: calc(100vh - 132px);

  object-fit: contain;

  border-radius: var(--radius-card);

  background: var(--surface);
}

.explainer-lightbox figcaption {
  margin: 12px 42px 0 4px;

  color: var(--text-soft);
  font-size: var(--text-sm);
  line-height: 1.45;
}

.explainer-lightbox-close {
  position: absolute;
  z-index: 2;
  top: 12px;
  right: 12px;

  width: 34px;
  height: 34px;
  padding: 0;

  display: grid;
  place-items: center;

  border: 1px solid var(--border-strong);
  border-radius: var(--radius-pill);

  background: var(--surface-frosted-strong);

  color: var(--text);
  font-size: 1.25rem;
  line-height: 1;

  cursor: pointer;
}

.explainer-lightbox-close:hover {
  border-color: rgba(255, 31, 31, 0.28);

  color: var(--red);
}

.explainer-lightbox-close:focus-visible {
  outline: 2px solid var(--blue);
  outline-offset: 3px;

  box-shadow: var(--shadow-focus);
}


/* ============================================================
   RESPONSIVE
   ============================================================ */

@media (max-width: 760px) {
  .explainer-index {
    padding:
      var(--space-12)
      0
      var(--space-20);
  }

  .explainer-index-header {
    margin-bottom: var(--space-8);
  }

  .explainer-index-header h1,
  .explainer-topic-header h1 {
    font-size: clamp(2.2rem, 12vw, 3.1rem);
  }

  .explainer-index-lede,
  .explainer-topic-deck {
    font-size: var(--text-base);
  }

  .explainer-groups,
  .explainer-directory-section {
    margin-top: var(--space-12);
    padding-top: var(--space-8);
  }

  .explainer-group-grid,
  .explainer-directory {
    grid-template-columns: minmax(0, 1fr);
  }

  .explainer-group-card,
  .explainer-card {
    padding: var(--space-5);
  }

  .explainer-topic {
    padding:
      var(--space-10)
      0
      var(--space-20);
  }

  .explainer-topic-header {
    margin-top: var(--space-8);
  }

  .explainer-topic-nav {
    gap: var(--space-4);
  }

  .explainer-topic-nav-link {
    max-width: 48%;
  }

  .explainer-topic-nav-name {
    font-size: 0.8rem;
  }

  .explainer-topic-body {
    margin-top: var(--space-12);
  }

  .explainer-topic-section + .explainer-topic-section {
    margin-top: var(--space-10);
    padding-top: var(--space-8);
  }

  .explainer-topic-section h2 {
    font-size: clamp(1.45rem, 7vw, 1.85rem);
  }

  .explainer-topic-section p {
    line-height: 1.72;
  }

  .explainer-topic-section--emphasis {
    padding-left: var(--space-5);
  }

  .explainer-visual {
    width: min(100%, calc(100% - 16px));
    margin:
      var(--space-10)
      auto
      var(--space-12);
    padding: var(--space-5);

    border-radius: 24px;
  }

  .explainer-visual-copy {
    margin-bottom: var(--space-5);

    text-align: left;
  }

  .explainer-visual-frame {
    max-width: 100%;
    padding: 9px;

    border-radius: 20px;
  }

  .explainer-visual-trigger {
    padding: 6px;

    border-radius: 15px;
  }

  .explainer-lightbox {
    width: calc(100vw - 18px);
    padding: 10px;

    border-radius: 22px;
  }

  .explainer-lightbox img {
    max-height: calc(100vh - 112px);

    border-radius: 14px;
  }

  .explainer-lightbox figcaption {
    margin-right: 40px;

    font-size: 0.76rem;
  }
}


@media (max-width: 520px) {
  .explainer-index-subtitle {
    max-width: 34ch;
  }

  .explainer-boundary {
    padding: var(--space-5);

    border-radius: var(--radius-card);
  }

  .explainer-topic-nav-direction {
    font-size: 0.625rem;
  }

  .explainer-topic-nav-name {
    font-size: 0.75rem;
  }

  .explainer-related-terms {
    gap:
      var(--space-3)
      var(--space-4);
  }
}


/* ============================================================
   REDUCED MOTION
   ============================================================ */

@media (prefers-reduced-motion: reduce) {
  .explainer-card,
  .explainer-card-cta::after,
  .explainer-topic-nav-name,
  .explainer-topic-section a {
    transition: none;
  }

  .explainer-card:hover {
    transform: none;
  }
}