/* Guide-specific layout and components. */

main { position: relative; z-index: 10; max-width: 1200px; margin: 0 auto; padding: 1.75rem 2rem 2rem; }

/* No horizontal scrollbar on any device. A single wide element (old
   captured-poses table, a too-wide inline code block, etc.) used to
   push the entire viewport sideways on phones — now anything that
   overflows gets clipped at the document edge instead. */
html { overflow-x: clip; }
body { overflow-x: hidden; max-width: 100vw; }

/* ─── universal text-readability backdrop ─────────────────────────────────
   The animated background (grid + nebula + scan-line + noise) sits at
   z-index 0-3. Plain text floating directly over it gets visually
   chopped by the scanlines. Any prose container that doesn't already
   have its own opaque-ish background gets one here. Use a CSS variable
   so individual sections can opt out by overriding it.
   --text-bg: rgba(4, 4, 12, 0.78) → solid-feeling, still glows through */

.topic-content > details.section-collapse,
.topic-content > details.section-collapse > summary,
.topic-content .topic-section,
.topic-content p,
.topic-content ul:not(.module-list):not(.topic-grid):not(.rail-topics):not(.rail-toc):not(.paper-list):not(.software-list):not(.part-list),
.topic-content ol,
.topic-content blockquote,
.topic-content .callout,
.topic-content .vs-card,
.topic-content .example-card,
.topic-content .technique-card,
.topic-content .anim-placeholder,
main > section > p,
main > section > ul,
main > section > ol,
main > .topic-hero {
  /* let already-styled cards keep their own bg; only fall back if none */
}

/* The collapsible section body is the most common offender. */
details.section-collapse > div,
details.section-collapse > p,
details.section-collapse > ul,
details.section-collapse > ol,
details.section-collapse > blockquote,
details.section-collapse > pre,
details.section-collapse > table,
details.section-collapse > .callout,
details.section-collapse > .technique-grid,
details.section-collapse > .topic-grid,
details.section-collapse > .vs-grid,
details.section-collapse > .example-grid {
  position: relative;
}

/* Plain prose inside topic content — wrap each direct text node container
   in a soft backdrop so the scanlines stop chopping the letters. */
.topic-content > .topic-section,
.topic-section .vs-card,
.topic-section .example-card,
.topic-section .technique-card,
.topic-section .callout,
.topic-section .anim-placeholder,
.hero,
.topic-hero {
  background: rgba(4, 4, 12, 0.78);
  border-radius: 6px;
  position: relative;
}
.topic-section { padding: 0 0; }
.topic-section > details.section-collapse { padding: 14px 18px; }

/* The summary needs a backdrop too since it sits at the top of each section. */
details.section-collapse > summary {
  background: rgba(4, 4, 12, 0.85);
  margin-left: -18px;
  margin-right: -18px;
  padding-left: 30px;
  padding-right: 18px;
}

/* Lists rendered as references (paper-list, software-list, part-list) — each li
   already has its own bg. But the outer ul backdrop helps when the list is
   short. */
.paper-list, .software-list, .part-list { background: transparent; }

/* Topic hero / section headings get a fully solid backdrop so the headline
   pops against the nebula + scanlines. */
.topic-hero {
  background: rgba(4, 4, 12, 0.86);
  padding: 1.5rem 1.6rem 2rem;
  border-radius: 8px;
}
.topic-hero h1 { background: transparent; }

/* Top-level page sections (about, glossary, landing) sit on a solid
   backdrop, since they're long-form prose and pages have no rail. */
main > section { background: rgba(4, 4, 12, 0.78); border-radius: 8px; padding: 18px 22px; margin-bottom: 16px; }
main > section h2 { background: transparent; border-bottom-color: rgba(0,224,255,0.25); }
main > section h2:first-child { margin-top: 0; }

/* Glossary list cards already have a left border; give them a backdrop too. */
.glossary-list dd { background: rgba(4,4,12,0.6); padding: 6px 12px 6px 16px; border-radius: 4px; }
.glossary-list dt { padding: 0 6px; }

/* Code spans were a little too transparent — bump them. */
code { background: rgba(0, 0, 0, 0.55); }

/* Featured/recommended block already has its own gradient, just bump opacity. */
.featured-block { background-color: rgba(0, 0, 0, 0.45); }
.featured-block li { background: rgba(0, 0, 0, 0.65); }

/* ───────────── landing hero ───────────── */

.hero {
  padding: 4rem 0 3rem;
  text-align: center;
  position: relative;
}
.hero h1 {
  font-size: clamp(2rem, 5vw, 3.4rem);
  letter-spacing: 0.02em;
  text-shadow: 0 0 24px rgba(168, 85, 247, 0.45),
               0 0 40px rgba(0, 224, 255, 0.18);
}
.hero h1 .glow-cyan { color: var(--accent-cyan); }
.hero h1 .glow-purple { color: var(--accent-purple); }
.hero .subhead {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 640px;
  margin: 1rem auto;
}
.hero .pill-row {
  display: inline-flex; gap: 8px; flex-wrap: wrap; justify-content: center;
  margin-top: 1.5rem;
}
.hero .pill {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  padding: 6px 14px;
  border-radius: 14px;
  background: rgba(0, 224, 255, 0.06);
  color: var(--accent-cyan);
  border: 1px solid rgba(0, 224, 255, 0.25);
}

/* ───────────── topic grid ───────────── */

.topic-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 14px;
  margin-top: 1.5rem;
}

.topic-card {
  display: block;
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 8px;
  padding: 1.1rem 1.2rem 1.2rem;
  text-decoration: none;
  color: inherit;
  position: relative;
  overflow: hidden;
  transition: all 280ms cubic-bezier(0.4, 0, 0.2, 1);
  backdrop-filter: blur(12px);
}
.topic-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0; height: 2px;
  background: var(--card-color, linear-gradient(90deg, var(--accent-cyan), var(--accent-purple)));
  opacity: 0.7;
  transition: opacity 280ms;
}
.topic-card:hover {
  border-color: var(--card-color, var(--accent-cyan));
  transform: translateY(-2px);
  box-shadow:
    0 0 0 1px rgba(0, 224, 255, 0.15),
    0 8px 28px -10px var(--card-color, rgba(0, 224, 255, 0.4)),
    0 4px 16px -8px rgba(168, 85, 247, 0.25);
}
.topic-card:hover::before { opacity: 1; }
/* Hex-framed icon holder: the emoji sits inside a rotated square with a
   neon ring in the card's category colour. Pulses on hover so the whole
   card feels alive and obviously interactive. */
.topic-card .icon-frame {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 54px; height: 54px;
  margin: 0 0 0.7rem;
  clip-path: polygon(50% 0%, 93% 25%, 93% 75%, 50% 100%, 7% 75%, 7% 25%);
  background:
    linear-gradient(135deg, var(--card-color, var(--accent-cyan)), transparent 75%),
    rgba(8, 12, 20, 0.85);
  border: 1px solid var(--card-color, var(--accent-cyan));
  box-shadow: 0 0 18px -2px var(--card-color, var(--accent-cyan));
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1),
              box-shadow 300ms;
}
.topic-card .icon-frame .icon-glow {
  position: absolute; inset: 3px;
  clip-path: inherit;
  background: radial-gradient(circle at 30% 30%,
              var(--card-color, var(--accent-cyan)) 0%,
              transparent 60%);
  opacity: 0.35;
  mix-blend-mode: screen;
  transition: opacity 300ms;
}
.topic-card .icon {
  font-size: 1.7rem;
  line-height: 1;
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1;
  /* Emoji baselines render ~2px below the geometric middle; nudge up so
     it reads as centred inside the hex. */
  padding-bottom: 2px;
  filter: drop-shadow(0 0 4px var(--card-color, var(--accent-cyan)));
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1);
}
.topic-card:hover .icon-frame {
  transform: rotate(12deg) scale(1.08);
  box-shadow: 0 0 28px -2px var(--card-color, var(--accent-cyan));
}
.topic-card:hover .icon-frame .icon-glow { opacity: 0.7; }
.topic-card:hover .icon { transform: rotate(-12deg) scale(1.1); }
.topic-card h3 {
  margin: 0 0 0.3rem;
  font-size: 1rem;
  font-weight: 600;
}
.topic-card .subhead {
  font-size: 0.82rem;
  color: var(--text-secondary);
  margin: 0;
}
.topic-card .card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
  margin-top: 0.8rem;
}
.topic-card .category-pill {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.62rem;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-dim);
  border: 1px solid var(--border-base);
}
/* "open →" affordance — visible at all times so clickability is obvious,
   intensifies on hover. */
.topic-card .card-cta {
  display: inline-flex;
  align-items: center;
  gap: 0.35em;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  font-weight: 700;
  color: var(--card-color, var(--accent-cyan));
  opacity: 0.65;
  transition: opacity 300ms, transform 300ms;
}
.topic-card .card-cta-arrow {
  display: inline-block;
  transition: transform 300ms cubic-bezier(0.4, 0, 0.2, 1);
}
.topic-card:hover .card-cta { opacity: 1; }
.topic-card:hover .card-cta-arrow { transform: translateX(6px); }
.topic-card { cursor: pointer; }

/* "start here" treatment for the fundamentals topic card */
.topic-card.start-here {
  background:
    linear-gradient(135deg, rgba(255, 107, 157, 0.12), rgba(168, 85, 247, 0.08)),
    var(--bg-panel);
  border-color: rgba(255, 107, 157, 0.45);
}
.topic-card.start-here::before {
  background: linear-gradient(90deg, var(--accent-pink), var(--accent-purple));
  opacity: 1;
  height: 3px;
}
.start-here-pill {
  position: absolute;
  top: 12px; right: 12px;
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-pink);
  background: rgba(255, 107, 157, 0.12);
  border: 1px solid rgba(255, 107, 157, 0.45);
  padding: 2px 8px;
  border-radius: 10px;
  text-shadow: 0 0 6px rgba(255, 107, 157, 0.5);
}

/* ─────────── intrinsics-vs-extrinsics page ─────────── */
.vs-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 14px;
  margin: 1rem 0 0.5rem;
}
@media (max-width: 720px) { .vs-grid { grid-template-columns: 1fr; } }

.vs-card {
  position: relative;
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 8px;
  padding: 1.4rem 1.5rem 1.3rem;
  overflow: hidden;
}
.vs-card.vs-int { border-color: rgba(0, 224, 255, 0.4); }
.vs-card.vs-int::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-cyan), transparent);
}
.vs-card.vs-ext { border-color: rgba(168, 85, 247, 0.4); }
.vs-card.vs-ext::before {
  content: '';
  position: absolute; top: 0; left: 0; right: 0; height: 2px;
  background: linear-gradient(90deg, transparent, var(--accent-purple), transparent);
}

.vs-tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  padding: 2px 10px;
  border-radius: 10px;
  margin-bottom: 0.7rem;
}
.vs-int .vs-tag {
  color: var(--accent-cyan);
  background: rgba(0, 224, 255, 0.1);
  border: 1px solid rgba(0, 224, 255, 0.3);
}
.vs-ext .vs-tag {
  color: var(--accent-purple);
  background: rgba(168, 85, 247, 0.1);
  border: 1px solid rgba(168, 85, 247, 0.3);
}
.vs-card h3 { margin: 0.2rem 0 0.5rem; font-size: 1.05rem; }
.vs-card p { color: var(--text-secondary); }

.example-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
  gap: 12px;
  margin-top: 1rem;
}
.example-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 6px;
  padding: 1rem 1.15rem;
}
.example-card h3 {
  margin: 0 0 0.4rem;
  font-size: 1rem;
  font-family: var(--font-mono);
  letter-spacing: 0.06em;
}
.example-card p { font-size: 0.86rem; }
.example-card .small { font-size: 0.75rem; }
.example-card ul { padding-left: 1rem; margin: 0.4rem 0; }
.example-card ul li { font-size: 0.82rem; padding: 0.2rem 0; }

.callout {
  padding: 0.85rem 1.1rem;
  border-radius: 6px;
  margin: 1rem 0;
  font-size: 0.92rem;
  border: 1px solid;
}
.callout.callout-amber {
  background: rgba(240, 176, 32, 0.06);
  border-color: rgba(240, 176, 32, 0.4);
  color: var(--text-primary);
}
.callout.callout-amber strong { color: var(--accent-amber); }

/* ─────────── topic page layout ─────────── */

.topic-page { display: grid; grid-template-columns: 220px 1fr; gap: 2rem; }

.topic-rail {
  position: sticky;
  top: 1rem;
  align-self: start;
  max-height: calc(100vh - 2rem);
  overflow-y: auto;
  padding: 1rem 0;
  border-right: 1px solid var(--border-base);
}

/* ── Mobile rail-drawer ──────────────────────────────────────────────
   At ≤900px the rail becomes an off-canvas drawer that slides in from
   the left (instead of stacking above the page hero, which ate the
   above-the-fold real estate). `.rail-toggle` in the site header opens
   the drawer, a backdrop dims the content, and the drawer closes on:
     (a) clicking any link inside it,
     (b) clicking the backdrop, or
     (c) pressing Escape.
   On wider screens `.rail-toggle` is hidden and the rail stays as a
   persistent sticky sidebar. */
@media (max-width: 900px) {
  .topic-page { grid-template-columns: 1fr; }
  .rail-toggle { display: inline-flex; }
  .topic-rail, .all-anims-toc {
    position: fixed !important;
    top: 0; left: 0; bottom: 0;
    width: min(320px, 82vw);
    max-height: 100vh !important;
    padding: 4.5rem 1.25rem 2rem;
    background: var(--bg-panel, rgba(4, 4, 12, 0.96));
    border-right: 1px solid var(--border-base);
    box-shadow: 8px 0 40px rgba(0, 0, 0, 0.6);
    z-index: 50;
    transform: translateX(-101%);
    transition: transform 220ms ease;
    /* Explicit auto + touch-action so iOS Safari and Chromium both
       allow scrolling the drawer content vertically even when
       `body { overflow: hidden }` is set (which we do via rail-open
       to lock the page behind the drawer). */
    overflow-y: auto;
    -webkit-overflow-scrolling: touch;
    overscroll-behavior: contain;
  }
  body.rail-open .topic-rail,
  body.rail-open .all-anims-toc {
    transform: translateX(0);
  }
  /* Backdrop — a REAL sibling element injected by nav.js at body level
     (not a `body::before` pseudo-element). Reason: `main` has
     `position: relative; z-index: 10`, which creates a stacking context
     at z-10 in the root context. The drawer (`.topic-rail`) lives
     inside that context. A pseudo-backdrop on body at z-40 sat in the
     root context ABOVE main(10), eating clicks on drawer links. Having
     the backdrop as a direct child of body lets it sit between main
     (z-10) and the drawer, which nav.js also appends to body on open
     so it joins the root stacking context at z-50 > 40. */
  .rail-backdrop {
    display: none;
    position: fixed; inset: 0;
    background: rgba(0, 0, 0, 0.55);
    backdrop-filter: blur(2px);
    z-index: 40;
    pointer-events: auto;
  }
  body.rail-open .rail-backdrop { display: block; }
  body.rail-open { overflow: hidden; }
}

/* Section collapsibles (auto-wrapped by js/nav.js) */
details.section-collapse { display: block; }
details.section-collapse > summary {
  cursor: pointer; list-style: none;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--accent-cyan);
  margin: 0 0 0.7rem;
  padding: 0.55rem 0 0.55rem 1.6rem;
  border-bottom: 1px solid var(--border-base);
  position: relative;
  user-select: none;
  transition: color 160ms;
}
details.section-collapse > summary::-webkit-details-marker { display: none; }
/* Cyberpunk chevron: a filled right-pointing neon triangle that rotates
   90° when the section opens. Bigger + more glowing than the plain `▸`
   so the "click to expand" affordance is obvious at a glance. */
details.section-collapse > summary::before {
  content: "";
  position: absolute; left: 0.35rem; top: 50%;
  width: 0; height: 0;
  border-top: 5px solid transparent;
  border-bottom: 5px solid transparent;
  border-left: 8px solid var(--accent-purple);
  transform: translateY(-50%);
  filter: drop-shadow(0 0 6px rgba(168, 85, 247, 0.55));
  transition: transform 240ms cubic-bezier(0.4, 0, 0.2, 1),
              border-left-color 200ms, filter 200ms;
}
details.section-collapse[open] > summary::before {
  transform: translateY(-50%) rotate(90deg);
  border-left-color: var(--accent-cyan);
  filter: drop-shadow(0 0 8px rgba(0, 224, 255, 0.7));
}
details.section-collapse > summary:hover {
  color: var(--accent-pink);
}
details.section-collapse > summary:hover::before {
  border-left-color: var(--accent-pink);
  filter: drop-shadow(0 0 10px rgba(255, 107, 157, 0.75));
}
details.section-collapse[open] > summary { border-bottom-color: rgba(0, 224, 255, 0.4); }

/* References sub-collapsibles (rendered by js/citations.js) */
details.ref-collapse {
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 6px;
  padding: 0.5rem 0.85rem;
  margin: 0.55rem 0;
}
details.ref-collapse > summary {
  cursor: pointer; list-style: none;
  display: flex; align-items: center; gap: 0.4rem;
  font-family: var(--font-mono);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  color: var(--text-primary);
  padding: 0.3rem 0 0.3rem 1.2rem;
  position: relative;
  user-select: none;
}
details.ref-collapse > summary::-webkit-details-marker { display: none; }
details.ref-collapse > summary::before {
  content: "▸";
  position: absolute; left: 0; top: 0.3rem;
  color: var(--accent-purple);
  transition: transform 200ms;
}
details.ref-collapse[open] > summary::before { transform: rotate(90deg); }
.ref-label { font-weight: 600; }
.ref-count {
  margin-left: auto;
  color: var(--text-dim);
  font-size: 0.72rem;
  background: rgba(255, 255, 255, 0.04);
  padding: 1px 8px;
  border-radius: 10px;
  border: 1px solid var(--border-base);
}

/* Featured / recommended pick treatment for top-pick items */
.featured-block {
  background: linear-gradient(135deg, rgba(48, 232, 104, 0.08), rgba(0, 224, 255, 0.04));
  border: 1px solid rgba(48, 232, 104, 0.4);
  border-radius: 6px;
  padding: 0.85rem 1rem;
  margin: 0.6rem 0 1rem;
  position: relative;
}
.featured-block::before {
  content: "★ RECOMMENDED";
  position: absolute;
  top: -10px; left: 14px;
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.18em;
  color: var(--accent-green);
  background: var(--bg-dark);
  padding: 2px 8px;
  border-radius: 10px;
  border: 1px solid rgba(48, 232, 104, 0.45);
  text-shadow: 0 0 6px rgba(48, 232, 104, 0.5);
}
.featured-block ul { list-style: none; padding: 0; display: grid; gap: 6px; }
.featured-block li {
  background: rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(60, 60, 80, 0.35);
  border-radius: 4px;
  padding: 0.5rem 0.8rem;
  font-size: 0.85rem;
}
.featured-block .featured-tag {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-left: 6px;
  padding: 1px 6px;
  border-radius: 8px;
  background: rgba(0, 224, 255, 0.1);
  color: var(--accent-cyan);
  border: 1px solid rgba(0, 224, 255, 0.3);
}
.featured-block .featured-tag.recent { background: rgba(48, 232, 104, 0.1); color: var(--accent-green); border-color: rgba(48, 232, 104, 0.3); }
.featured-block .featured-tag.seminal { background: rgba(168, 85, 247, 0.1); color: var(--accent-purple); border-color: rgba(168, 85, 247, 0.3); }

/* Richer sidebar */
.topic-rail .rail-block { margin-bottom: 1.5rem; padding-right: 0.8rem; }

/* Main-nav block — visible inside the rail on mobile (when the rail is
   a drawer) and hidden on desktop (where the header's in-place nav
   already shows the site menu). */
.rail-main-nav { display: none; }
@media (max-width: 900px) {
  .rail-main-nav { display: block; }
  .rail-main-nav .rail-toc a[aria-current="page"],
  .rail-main-nav .rail-toc a.current {
    color: var(--accent-cyan);
    border-left-color: var(--accent-cyan);
    background: rgba(0, 224, 255, 0.06);
  }
}
.topic-rail .rail-cap {
  font-family: var(--font-mono);
  font-size: 0.62rem;
  text-transform: uppercase;
  letter-spacing: 0.18em;
  color: var(--text-dim);
  margin: 0 0 0.5rem;
}
.topic-rail .rail-actions { display: flex; gap: 4px; margin: 0 0 0.5rem; }
.rail-btn {
  font-family: var(--font-mono);
  font-size: 0.6rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  padding: 2px 8px;
  border-radius: 10px;
  background: rgba(0, 224, 255, 0.06);
  color: var(--text-secondary);
  border: 1px solid rgba(0, 224, 255, 0.18);
  cursor: pointer;
  transition: all 120ms;
}
.rail-btn:hover { color: var(--accent-cyan); border-color: var(--accent-cyan); background: rgba(0, 224, 255, 0.14); }

.topic-rail .rail-toc { list-style: none; padding: 0; margin: 0; }
.topic-rail .rail-toc a {
  display: block;
  font-size: 0.82rem;
  color: var(--text-secondary);
  padding: 0.28rem 0 0.28rem 0.7rem;
  border-left: 2px solid transparent;
  transition: all 120ms;
  text-decoration: none;
}
.topic-rail .rail-toc a:hover, .topic-rail .rail-toc a.active {
  color: var(--accent-cyan);
  border-left-color: var(--accent-cyan);
  background: linear-gradient(90deg, rgba(0, 224, 255, 0.08), transparent);
}

.topic-rail details.rail-group { margin: 0.4rem 0; }
.topic-rail details.rail-group > summary {
  cursor: pointer; list-style: none;
  display: flex; align-items: center; gap: 6px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-secondary);
  padding: 0.35rem 0 0.35rem 1rem;
  border-bottom: 1px solid rgba(60, 60, 80, 0.18);
  position: relative;
}
.topic-rail details.rail-group > summary::-webkit-details-marker { display: none; }
.topic-rail details.rail-group > summary::before {
  content: "▸";
  position: absolute; left: 0; top: 0.35rem;
  color: var(--accent-purple);
  transition: transform 200ms;
}
.topic-rail details.rail-group[open] > summary::before { transform: rotate(90deg); }
.topic-rail details.rail-group .rail-count {
  margin-left: auto;
  color: var(--text-dim);
  font-size: 0.62rem;
  font-weight: 400;
  letter-spacing: 0.04em;
  background: rgba(255, 255, 255, 0.03);
  padding: 1px 6px;
  border-radius: 8px;
  border: none;
}
.topic-rail .rail-topics { list-style: none; padding: 0.3rem 0 0.6rem; margin: 0; }
.topic-rail .rail-topics a {
  display: flex; align-items: center; gap: 7px;
  font-size: 0.78rem;
  color: var(--text-secondary);
  padding: 0.22rem 0.4rem;
  border-radius: 4px;
  border-left: 2px solid transparent;
  margin: 1px 0;
  text-decoration: none;
  transition: all 120ms;
}
.topic-rail .rail-topics a:hover { color: var(--text-primary); background: rgba(0, 224, 255, 0.06); }
.topic-rail .rail-topics a.current {
  color: var(--card-color, var(--accent-cyan));
  background: linear-gradient(90deg, rgba(0, 224, 255, 0.1), transparent);
  border-left-color: var(--card-color, var(--accent-cyan));
  font-weight: 600;
}
.topic-rail .rail-icon { font-size: 1rem; flex-shrink: 0; filter: drop-shadow(0 0 4px var(--card-color, transparent)); }
.topic-rail .rail-title { line-height: 1.3; }

.topic-rail .rail-meta {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  display: flex; flex-direction: column; gap: 0.4rem;
  padding-top: 0.8rem;
  border-top: 1px solid var(--border-base);
}
.topic-rail .rail-meta a { color: var(--accent-purple); text-decoration: none; }
.topic-rail .rail-meta a:hover { color: var(--accent-pink); }

.topic-content { min-width: 0; }

.topic-hero {
  padding: 1.5rem 0 2rem;
  border-bottom: 1px solid var(--border-base);
  margin-bottom: 1.5rem;
}
.topic-hero .kicker {
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.2em;
  color: var(--accent-purple);
  margin-bottom: 0.6rem;
}
.topic-hero h1 { margin: 0; font-size: 2.2rem; }
.topic-hero .subhead {
  margin-top: 0.6rem;
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 720px;
}

/* Hero acronym expansion: "MR·CAL GUIDE = Multiple Robot Calibration Guide",
   shown subtly under the main brand so first-time visitors understand the
   name while keeping the "Mr. Cal" personality. */
.hero-expansion {
  margin: 0.5rem 0 0;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.08em;
  color: var(--text-secondary);
}
.hero-expansion strong { color: var(--accent-cyan); font-weight: 700; }
.hero-expansion em { color: var(--text-dim); font-style: italic; }

/* Hero call-to-action row (Download button etc). */
.topic-hero .hero-actions {
  margin: 1.5rem 0 0.2rem;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 1rem;
  font-size: 0.95rem;
}
.cta-button {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
  font-family: var(--font-mono);
  font-size: 0.84rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  font-weight: 700;
  padding: 0.85rem 1.5rem 0.85rem 1rem;
  border-radius: 6px;
  color: #04040c;
  background: var(--accent-cyan);
  border: 1px solid var(--accent-cyan);
  text-decoration: none;
  box-shadow:
    0 0 24px rgba(0, 224, 255, 0.45),
    inset 0 1px 0 rgba(255, 255, 255, 0.3);
  transition: transform 180ms, box-shadow 180ms, background 180ms;
  position: relative;
  overflow: hidden;
}
/* Soft pulse so the button draws attention on load. */
.cta-button::after {
  content: '';
  position: absolute;
  inset: -2px;
  border-radius: inherit;
  border: 2px solid var(--accent-cyan);
  animation: ctaPulse 2.6s ease-out infinite;
  pointer-events: none;
}
@keyframes ctaPulse {
  0%   { transform: scale(1);    opacity: 0.55; }
  80%  { transform: scale(1.18); opacity: 0; }
  100% { transform: scale(1.22); opacity: 0; }
}
.cta-button:hover {
  transform: translateY(-2px);
  background: #3dedff;
  box-shadow:
    0 0 36px rgba(0, 224, 255, 0.7),
    inset 0 1px 0 rgba(255, 255, 255, 0.35);
}
.cta-button:active { transform: translateY(0); }
.cta-button .cta-icon {
  width: 28px; height: 28px; flex-shrink: 0;
  color: #04040c;
}
.cta-button .cta-tag {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px; height: 22px;
  border-radius: 50%;
  background: rgba(4, 4, 12, 0.85);
  color: var(--accent-cyan);
  font-size: 0.75rem;
  font-weight: 700;
  animation: ctaBounce 1.8s ease-in-out infinite;
}
@keyframes ctaBounce {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(2px); }
}
.cta-sub { color: var(--text-secondary); font-size: 0.85rem; }

.topic-section { margin: 2.5rem 0; scroll-margin-top: 1rem; }

/* ── universal link-hover treatment ─────────────────────────────────
   Every in-prose link gets an animated gradient underline that grows on
   hover, so links are obviously interactive without being visually
   loud in their resting state. Applied to content links; NAV/rail/
   button links opt out via their own classes or explicit `no-underline`. */
.topic-content a:not(.topic-link):not(.cta-button):not(.rail-toc a):not(.rail-topics a):not(.cite),
.topic-hero a:not(.cta-button),
.hero a,
main > section p a,
.topic-section p a,
.narration-panel .caption-narration a {
  color: var(--accent-cyan);
  text-decoration: none;
  background-image: linear-gradient(90deg,
    var(--accent-cyan), var(--accent-purple));
  background-size: 0% 1.5px;
  background-position: 0 100%;
  background-repeat: no-repeat;
  transition: background-size 220ms, color 220ms, text-shadow 220ms;
  padding-bottom: 1px;
}
.topic-content a:not(.topic-link):not(.cta-button):not(.rail-toc a):not(.rail-topics a):not(.cite):hover,
.topic-hero a:not(.cta-button):hover,
.hero a:hover,
main > section p a:hover,
.topic-section p a:hover,
.narration-panel .caption-narration a:hover {
  background-size: 100% 1.5px;
  color: #3dedff;
  text-shadow: 0 0 8px rgba(0, 224, 255, 0.45);
}

/* Buttons, summaries, and any element carrying `cursor:pointer` gets a
   subtle lift+glow on hover, so clickable affordance is uniform. */
button:not(:disabled),
summary,
[role="button"],
.card-cta { cursor: pointer; }

button:not(:disabled):hover,
.rail-toggle:hover,
details.section-collapse > summary:hover {
  filter: brightness(1.15);
}

/* Animation chrome stack:
     [.anim-title]  — title bar above (sibling, mounted by nav.js)
     [.anim-host]   — the canvas itself
     [.narration-panel] — captions + voice controls (sibling, by narration.js)
   Everything is a vertically-stacked sibling. The .anim-host has its own
   borders only on the sides + nothing else; the title and panel finish the
   visual frame. */

.anim-title {
  background: rgba(4, 4, 12, 0.94);
  border: 1px solid var(--border-base);
  border-bottom: 1px solid rgba(168, 85, 247, 0.25);
  border-radius: 8px 8px 0 0;
  padding: 10px 16px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent-purple);
}
.anim-title-label {
  font-weight: 700;
  color: var(--accent-cyan);
  text-shadow: 0 0 10px rgba(0, 224, 255, 0.35);
}
.anim-title-beat {
  font-family: var(--font-body);
  font-size: 0.85rem;
  letter-spacing: 0.02em;
  text-transform: none;
  color: var(--text-secondary);
}
.anim-title-beat:empty::before {
  content: "ready";
  color: var(--text-dim);
  font-family: var(--font-mono);
  font-size: 0.74rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
}

.anim-host {
  background: radial-gradient(ellipse at center, #04080f 0%, #000000 80%);
  border-left: 1px solid var(--border-base);
  border-right: 1px solid var(--border-base);
  border-radius: 0;
  border-top: none;
  border-bottom: none;
  min-height: 540px;
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
  box-shadow: inset 0 0 32px rgba(0, 224, 255, 0.04);
}
@media (max-width: 720px) {
  .anim-host { min-height: 440px; }
}
/* Narrow-phone canvas breakout.
   `main` carries a generous 2rem horizontal padding for prose readability,
   but the animation canvas and its sibling title + narration panels are
   fixed-width HUD-heavy components that need every pixel of horizontal
   room they can get on phone. Negative margins pull them out of the
   prose padding and restore ~64 lost pixels of canvas width at 430-CSS-px
   viewports. The sibling .anim-title and .narration-panel follow the
   host so the visual frame stays visually continuous. */
@media (max-width: 500px) {
  main { padding-left: 0.5rem; padding-right: 0.5rem; }
  .topic-content .anim-title,
  .topic-content .anim-host,
  .topic-content .narration-panel {
    margin-left: -0.5rem;
    margin-right: -0.5rem;
  }
  .anim-host { min-height: 480px; }
}
.anim-host:focus { outline: 2px solid rgba(0, 224, 255, 0.4); outline-offset: -2px; }

/* ── narration player (mounted by js/narration.js inside .anim-host) ── */
/* Narration panel — sibling below the .anim-host. Joined visually to
   the canvas (no top border, hard top corners). Now also acts as the
   universal "controls below" container — the play / step / replay
   buttons live in .narration-controls and are centred. */
.narration-panel {
  background: rgba(4, 4, 12, 0.94);
  border: 1px solid var(--border-base);
  border-top: 1px solid rgba(0, 224, 255, 0.18);
  border-radius: 0 0 8px 8px;
  margin-bottom: 1.25rem;
  padding: 14px 16px 12px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

/* Legacy positioning (still used if mountNarration falls back to
   appending inside the host). New code path uses .narration-panel
   above. */
.narration:not(.narration-panel) {
  position: absolute;
  left: 0; right: 0; bottom: 0;
  z-index: 5;
  pointer-events: none;
}
.narration-missing {
  position: absolute;
  bottom: 8px; right: 12px;
  z-index: 6;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  letter-spacing: 0.04em;
  color: var(--accent-amber);
  background: rgba(240, 176, 32, 0.1);
  border: 1px solid rgba(240, 176, 32, 0.4);
  border-radius: 12px;
  padding: 2px 10px;
}
.narration-caption {
  background: rgba(0, 0, 0, 0.4);
  border: 1px solid rgba(0, 224, 255, 0.18);
  border-radius: 6px;
  padding: 12px 16px;
  color: var(--text-primary);
  font-size: 1.02rem;
  line-height: 1.45;
  pointer-events: auto;
  transition: border-color 320ms, box-shadow 320ms;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.narration-caption.active {
  border-color: rgba(0, 224, 255, 0.6);
  box-shadow: 0 0 24px rgba(0, 224, 255, 0.12);
}
.narration-caption .caption-text {
  font-weight: 700;
  font-size: 1.08rem;
  color: var(--text-primary);
  letter-spacing: 0.01em;
}
.narration-caption .caption-narration {
  font-size: 0.94rem;
  font-weight: 400;
  color: var(--text-secondary);
  line-height: 1.6;
  min-height: 1em;
  text-align: left;
  /* Show the full narration. No max-height clip — what the user hears
     is what the user sees. */
}
.narration-caption .caption-narration:empty { display: none; }
.narration-caption .caption-narration mark {
  background: rgba(0, 224, 255, 0.18);
  color: var(--accent-cyan);
  padding: 0 2px;
  border-radius: 2px;
  font-weight: 600;
  text-shadow: 0 0 8px rgba(0, 224, 255, 0.4);
}
.narration-caption .caption-narration .spoken { color: var(--text-dim); }
.narration-caption .caption-narration .unspoken { color: var(--text-secondary); }
.narration-controls {
  display: flex;
  align-items: center;
  justify-content: center;       /* centred per user request */
  gap: 10px;
  padding: 4px 4px 0;
  pointer-events: auto;
  font-family: var(--font-mono);
  font-size: 0.82rem;
  flex-wrap: wrap;
}
/* Settings drawer floats to the right inside the centered control row. */
.narration-controls .narr-settings { margin-left: 12px; }
.narration-controls button,
.narration-controls .narr-progress,
.narration-controls .narr-settings > summary {
  background: rgba(4, 4, 12, 0.85);
  color: var(--text-secondary);
  border: 1px solid var(--border-base);
  border-radius: 14px;
  padding: 4px 10px;
  font: inherit;
  cursor: pointer;
  user-select: none;
  transition: all 140ms;
  list-style: none;
}
.narration-controls button:hover,
.narration-controls .narr-settings > summary:hover {
  color: var(--accent-cyan);
  border-color: var(--accent-cyan);
  background: rgba(0, 224, 255, 0.1);
}
.narration-controls .narr-toggle {
  font-weight: 700;
  letter-spacing: 0.04em;
  background: linear-gradient(135deg, rgba(0, 224, 255, 0.15), rgba(168, 85, 247, 0.12));
  border-color: rgba(0, 224, 255, 0.5);
  color: var(--accent-cyan);
  text-shadow: 0 0 8px rgba(0, 224, 255, 0.4);
}
.narration-controls .narr-toggle.speaking {
  background: linear-gradient(135deg, rgba(48, 232, 104, 0.25), rgba(0, 224, 255, 0.2));
  border-color: var(--accent-green);
  color: var(--accent-green);
  text-shadow: 0 0 10px rgba(48, 232, 104, 0.6);
  animation: speakingPulse 1.4s ease-in-out infinite;
}
@keyframes speakingPulse {
  0%, 100% { box-shadow: 0 0 0 0 rgba(48, 232, 104, 0.45); }
  50%      { box-shadow: 0 0 0 6px rgba(48, 232, 104, 0); }
}
.narration-controls .narr-progress {
  cursor: default;
  pointer-events: none;
  color: var(--text-dim);
  letter-spacing: 0.04em;
}
.narration-controls .narr-settings > summary::-webkit-details-marker { display: none; }
/* Make the settings gear obvious: bigger icon + a text label next to it.
   Was a lone tiny "⚙" with no tooltip that users couldn't see or click. */
.narration-controls .narr-settings > summary {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  padding: 4px 12px;
}
.narration-controls .narr-gear {
  font-size: 1.1em;
  line-height: 1;
  filter: drop-shadow(0 0 4px rgba(0, 224, 255, 0.35));
  transition: transform 300ms;
}
.narration-controls .narr-settings[open] > summary .narr-gear,
.narration-controls .narr-settings > summary:hover .narr-gear {
  transform: rotate(60deg);
}
.narration-controls .narr-settings-label {
  font-size: 0.82em;
  letter-spacing: 0.06em;
  text-transform: lowercase;
}
.narration-controls .narr-settings { position: relative; }
.narration-controls .narr-settings[open] > .narr-settings-body {
  position: absolute;
  bottom: 36px; right: 0;
  min-width: 240px;
  background: rgba(4, 4, 12, 0.95);
  border: 1px solid rgba(0, 224, 255, 0.3);
  border-radius: 6px;
  padding: 12px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.6),
              0 0 16px rgba(0, 224, 255, 0.15);
}
.narr-settings-body label {
  display: block;
  margin-bottom: 10px;
  color: var(--text-secondary);
  font-size: 0.78rem;
}
.narr-settings-body select,
.narr-settings-body input[type="range"] {
  display: block;
  width: 100%;
  margin-top: 4px;
  background: rgba(0, 0, 0, 0.5);
  color: var(--text-primary);
  border: 1px solid var(--border-base);
  border-radius: 3px;
  padding: 4px 6px;
  font-family: var(--font-mono);
  font-size: 0.78rem;
}
.narr-rate-value {
  display: inline-block;
  margin-left: 6px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--accent-cyan);
}
.narr-tts-warn, .narr-tts-hint {
  margin: 0;
  padding: 6px 8px;
  background: rgba(240, 176, 32, 0.08);
  border: 1px solid rgba(240, 176, 32, 0.3);
  border-radius: 4px;
  color: var(--accent-amber);
  font-size: 0.7rem;
  line-height: 1.3;
}
.narr-tts-hint {
  background: rgba(0, 224, 255, 0.06);
  border-color: rgba(0, 224, 255, 0.25);
  color: var(--text-secondary);
}
.narr-voice-preview {
  margin-left: 6px;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  background: rgba(0, 224, 255, 0.1);
  color: var(--accent-cyan);
  border: 1px solid rgba(0, 224, 255, 0.3);
  border-radius: 10px;
  padding: 2px 8px;
  cursor: pointer;
}
.narr-voice-preview:hover { background: rgba(0, 224, 255, 0.2); }
@media (max-width: 720px) {
  .narration-controls { flex-wrap: wrap; gap: 4px; }
  .narration-caption { font-size: 0.85rem; padding: 8px 10px; }
}
.anim-host::after {
  content: '';
  position: absolute; inset: 0; pointer-events: none;
  background:
    radial-gradient(ellipse 80% 30% at 50% 0%, rgba(0, 224, 255, 0.08), transparent 60%),
    radial-gradient(ellipse 80% 30% at 50% 100%, rgba(168, 85, 247, 0.08), transparent 60%);
}

.anim-placeholder {
  text-align: center; max-width: 500px; padding: 2rem;
  color: var(--text-secondary);
  position: relative; z-index: 1;
}
.anim-placeholder .badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent-purple);
  background: rgba(168, 85, 247, 0.08);
  border: 1px solid rgba(168, 85, 247, 0.3);
  padding: 4px 10px;
  border-radius: 12px;
  margin-bottom: 1rem;
}
.anim-placeholder strong { display: block; font-size: 1.1rem; color: var(--text-primary); margin-bottom: 0.5rem; }
.anim-placeholder em { display: block; margin-top: 0.8rem; font-size: 0.78rem; color: var(--text-dim); }

/* ─────────── technique cards ─────────── */

.technique-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(310px, 1fr));
  gap: 12px;
}

.technique-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 6px;
  padding: 1rem 1.15rem;
  position: relative;
}
.technique-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; bottom: 0; width: 3px;
  background: linear-gradient(180deg, var(--accent-cyan), var(--accent-purple));
  border-radius: 6px 0 0 6px;
}
.technique-card h3 { margin: 0 0 0.5rem; font-size: 1rem; }
.technique-card p { font-size: 0.86rem; color: var(--text-secondary); }
.technique-card .meta {
  display: flex; flex-wrap: wrap; gap: 6px; margin-top: 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
}

/* ─────────── citation chips ─────────── */

.cite {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  padding: 1px 6px;
  border-radius: 3px;
  cursor: help;
  border: 1px solid transparent;
  transition: all 120ms;
  white-space: nowrap;
}
.cite-paper { background: rgba(0, 224, 255, 0.08); color: var(--accent-cyan); border-color: rgba(0, 224, 255, 0.2); }
.cite-paper::before { content: '📄 '; }
.cite-software { background: rgba(48, 232, 104, 0.08); color: var(--accent-green); border-color: rgba(48, 232, 104, 0.2); }
.cite-software::before { content: '📦 '; }
.cite-part { background: rgba(168, 85, 247, 0.08); color: var(--accent-purple); border-color: rgba(168, 85, 247, 0.2); }
.cite-part::before { content: '🔧 '; }
.cite-excluded { background: rgba(255, 71, 87, 0.08); color: var(--accent-red); border-color: rgba(255, 71, 87, 0.3); }
.cite-excluded::before { content: '⊘ '; }

.cite:hover { filter: brightness(1.3); transform: translateY(-1px); }

/* tooltip card on hover (positioned by JS) */
.cite-tooltip {
  position: absolute;
  z-index: 1500;
  max-width: 380px;
  background: var(--bg-panel);
  border: 1px solid var(--accent-cyan);
  border-radius: 6px;
  padding: 0.85rem 1rem;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.6),
              0 0 16px rgba(0, 224, 255, 0.2);
  font-size: 0.82rem;
  pointer-events: none;
  backdrop-filter: blur(12px);
}
.cite-tooltip strong { display: block; color: var(--text-primary); margin-bottom: 0.25rem; }
.cite-tooltip .meta { color: var(--text-dim); font-family: var(--font-mono); font-size: 0.72rem; }
.cite-tooltip a { color: var(--accent-cyan); }

/* ─────────── tradeoffs table ─────────── */

.tradeoffs-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 6px;
  overflow: hidden;
  font-size: 0.86rem;
}
.tradeoffs-table th {
  background: rgba(0, 0, 0, 0.4);
  padding: 0.7rem 1rem;
  text-align: left;
  font-family: var(--font-mono);
  font-size: 0.68rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  color: var(--text-dim);
  font-weight: 500;
  border-bottom: 1px solid var(--border-base);
}
.tradeoffs-table td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid rgba(60, 60, 80, 0.18);
  vertical-align: top;
}
.tradeoffs-table tr:last-child td { border-bottom: none; }
.tradeoffs-table tr:hover td { background: rgba(0, 224, 255, 0.03); }

/* ─────────── parts (hardware) cards ─────────── */

.part-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 12px;
}
.part-card {
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 6px;
  padding: 0.9rem 1rem;
  font-size: 0.85rem;
}
.part-card .name { font-weight: 600; color: var(--text-primary); }
.part-card .vendor { font-family: var(--font-mono); font-size: 0.7rem; color: var(--text-dim); }
.part-card dl { margin: 0.6rem 0 0; display: grid; grid-template-columns: auto 1fr; gap: 4px 12px; font-size: 0.78rem; }
.part-card dt { color: var(--text-dim); font-family: var(--font-mono); font-size: 0.72rem; }
.part-card dd { color: var(--text-primary); margin: 0; }
.part-card a.datasheet {
  display: inline-block; margin-top: 0.7rem;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  text-transform: uppercase;
  letter-spacing: 0.14em;
}

/* ─────────── reference lists ─────────── */

.paper-list, .software-list, .part-list {
  list-style: none; padding: 0;
  display: grid; gap: 6px;
}
.paper-list li, .software-list li, .part-list li {
  padding: 0.55rem 0.85rem;
  background: var(--bg-panel);
  border: 1px solid var(--border-base);
  border-radius: 4px;
  font-size: 0.85rem;
}
.paper-list .meta, .software-list .meta {
  display: block;
  margin-top: 2px;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  color: var(--text-dim);
}
.software-list .license-pill {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  padding: 1px 6px;
  border-radius: 3px;
  margin-left: 4px;
}
.license-pill.permissive { background: rgba(48, 232, 104, 0.1); color: var(--accent-green); }
.license-pill.copyleft   { background: rgba(255, 71, 87, 0.1); color: var(--accent-red); }
.license-pill.unverified { background: rgba(240, 176, 32, 0.1); color: var(--accent-amber); }

.search-box {
  display: block;
  width: 100%;
  margin-bottom: 0.8rem;
  padding: 0.6rem 0.85rem;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  background: rgba(0, 0, 0, 0.5);
  color: var(--text-primary);
  border: 1px solid var(--border-base);
  border-radius: 4px;
}
.search-box:focus { outline: none; border-color: var(--accent-cyan); box-shadow: 0 0 0 2px rgba(0, 224, 255, 0.2); }

/* ─────────── glossary ─────────── */

.glossary-list { display: grid; gap: 0.75rem; }
.glossary-list dt {
  font-weight: 700; color: var(--text-primary);
  font-size: 1.05rem;
  margin-top: 0.4rem;
}
.glossary-list dd { color: var(--text-secondary); margin: 0 0 0.4rem; padding-left: 0.4rem; border-left: 2px solid var(--accent-purple); }

/* ─────────── responsive ─────────── */

@media (max-width: 720px) {
  main { padding: 1rem 1rem 2rem; }
  .topic-grid { grid-template-columns: 1fr; }
  h1 { font-size: 1.6rem; }
}