/* ==========================================================================
   Jákli Lab — Design System
   Light & minimal. Single source of truth for the whole site.
   ========================================================================== */

/* ---- Design tokens ---- */
:root {
  /* Palette */
  --bg:            #ffffff;
  --bg-alt:        #f6f7f9;
  --bg-deep:       #0f1b2d;   /* dark hero / footer panels */
  --text:          #1a1d23;
  --text-soft:     #545b66;
  --border:        #e6e8ec;

  /* Accent — neutral blue/teal. Swap to Kent State navy (#002664) + gold (#EAAB00) later. */
  --accent:        #1f6f8b;
  --accent-strong: #16596f;
  --accent-soft:   #e8f1f4;

  /* Typography */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --font-head: "Plus Jakarta Sans", "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;

  /* Layout */
  --maxw: 1140px;
  --gutter: 1.5rem;
  --radius: 14px;
  --radius-sm: 8px;
  --shadow: 0 1px 2px rgba(16, 27, 45, 0.04), 0 8px 24px rgba(16, 27, 45, 0.06);
  --shadow-lg: 0 12px 40px rgba(16, 27, 45, 0.12);

  --transition: 180ms ease;
}

/* ---- Paper cutout theme (body.theme-paper) ----
   Elements read as flat paper sheets floating at different depths:
   warm paper tones, faint grain, layered soft shadows, slight tilts. */
body.theme-paper {
  --bg:            #f4eee2;
  --bg-alt:        #ece3d2;
  --bg-deep:       #2c2620;
  --text:          #2b2620;
  --text-soft:     #6c6354;
  --border:        #e2d8c4;

  --accent:        #1f7a86;
  --accent-strong: #155f69;
  --accent-soft:   #e0ece9;

  /* Paper depth shadows — a tight "edge" shadow (sheet thickness) + a soft cast shadow */
  --paper-low:  0 1px 0 #e6dcc8, 0 2px 6px rgba(70,57,38,0.10);
  --paper-mid:  0 2px 0 #e0d5bf, 0 8px 16px rgba(70,57,38,0.14);
  --paper-high: 0 3px 0 #dccfb6, 0 18px 34px rgba(70,57,38,0.20);

  background-color: var(--bg);
  /* faint paper fiber texture */
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='160' height='160'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2' stitchTiles='stitch'/%3E%3CfeColorMatrix type='saturate' values='0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)' opacity='0.04'/%3E%3C/svg%3E");
}

/* Parallax background image — fixed behind all content, drifts slower than the
   page. The landscape texture runs full width and is stacked vertically so it
   scrolls down the whole page. Used on every page. */
.page-bg {
  position: fixed;
  inset: 0;
  z-index: -1;
  pointer-events: none;
  background-image: url("../assets/images/home/bg-wide.png");
  background-repeat: repeat-y;
  background-size: 100% auto;
  background-position: center 0;
  opacity: 0.12;
  will-change: background-position;
}
/* Faint variant — texture barely visible so plain (non-card) text stays legible */
body.bg-faint .page-bg { opacity: 0.075; }

@media (prefers-reduced-motion: reduce) {
  .page-bg { will-change: auto; }
}

/* Header: a thin paper strip resting on the page */
body.theme-paper .site-header {
  background: rgba(244, 238, 226, 0.75);
  backdrop-filter: saturate(160%) blur(12px);
  -webkit-backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border);
  box-shadow: 0 2px 0 #e6dcc8, 0 6px 14px rgba(70,57,38,0.08);
}
body.theme-paper .nav__mark {
  background: linear-gradient(135deg, var(--accent), #3a9aa6);
  box-shadow: 0 2px 0 rgba(0,0,0,0.12);
}

/* Hero media: a photo-print pinned slightly askew, lifted highest */
body.theme-paper .hero {
  background: linear-gradient(
    to bottom,
    var(--bg) 0,
    var(--bg) calc(100% - 96px),
    transparent 100%
  );
}
body.theme-paper .ph--hero {
  box-shadow: var(--paper-high);
  transform: rotate(-1.2deg);
  border: 6px solid #fbf7ee;   /* paper border like a print */
}

/* Cards: cut sheets at varying depths + slight tilts */
body.theme-paper .card {
  border: 1px solid var(--border);
  background: #fbf7ee;
  box-shadow: var(--paper-mid);
  transition: transform var(--transition), box-shadow var(--transition);
}
body.theme-paper .grid--3 .card:nth-child(3n+1) { transform: rotate(-1deg); box-shadow: var(--paper-low); }
body.theme-paper .grid--3 .card:nth-child(3n+2) { transform: rotate(0.6deg) translateY(-6px); box-shadow: var(--paper-high); }
body.theme-paper .grid--3 .card:nth-child(3n+3) { transform: rotate(-0.4deg) translateY(-2px); box-shadow: var(--paper-mid); }
body.theme-paper .card:hover {
  transform: rotate(0deg) translateY(-10px) scale(1.01);
  box-shadow: var(--paper-high);
}

/* Placeholders look like colored paper layers */
body.theme-paper .ph {
  border: none;
  box-shadow: inset 0 0 0 1px rgba(70,57,38,0.06);
}
body.theme-paper .ph.t1 { background: linear-gradient(135deg, #cfe0dc, #e3efeb); }
body.theme-paper .ph.t2 { background: linear-gradient(135deg, #dfd6c0, #efe7d4); }
body.theme-paper .ph.t3 { background: linear-gradient(135deg, #e4cdbf, #f1ddd1); }

/* Buttons as little paper chips with thickness */
body.theme-paper .btn--primary { box-shadow: 0 3px 0 var(--accent-strong); }
body.theme-paper .btn--primary:hover { transform: translateY(1px); box-shadow: 0 2px 0 var(--accent-strong); }
body.theme-paper .btn--ghost { background: #fbf7ee; box-shadow: 0 3px 0 #e0d5bf; }
body.theme-paper .btn--ghost:hover { transform: translateY(1px); box-shadow: 0 2px 0 #e0d5bf; }

/* Section bands as stacked paper layers */
body.theme-paper .section--alt {
  background: var(--bg-alt);
  box-shadow: inset 0 2px 0 #efe6d4, inset 0 -2px 0 #ddd2bb;
}

/* Parallax pages: keep the alternating bands but fade their top/bottom edges
   so the texture blends in gradually instead of meeting a hard border. */
body.theme-paper.bg-parallax .section--alt {
  background: linear-gradient(
    to bottom,
    transparent 0,
    var(--bg-alt) 64px,
    var(--bg-alt) calc(100% - 64px),
    transparent 100%
  );
  box-shadow: none;
}

/* Full-texture pages (e.g. Events): once we transition into the texture below
   the hero, keep it the whole way down — no opaque alternating bands. */
body.theme-paper.bg-full .section--alt {
  background: transparent;
  box-shadow: none;
}

/* Mobile dropdown sheet — paper background only when it's the dropdown, so on
   desktop the links don't add a second tint on top of the header. */
@media (max-width: 768px) {
  body.theme-paper .nav__links { background: rgba(244, 238, 226, 0.75); }
}

/* ---- Reset / base ---- */
*, *::before, *::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--font-sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  font-size: 17px;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }

a { color: var(--accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-strong); }

h1, h2, h3, h4 {
  font-family: var(--font-head);
  line-height: 1.15;
  color: var(--text);
  margin: 0 0 0.5em;
  font-weight: 700;
  letter-spacing: -0.02em;
}
h1 { font-size: clamp(2.2rem, 5vw, 3.6rem); }
h2 { font-size: clamp(1.6rem, 3.5vw, 2.4rem); }
h3 { font-size: 1.25rem; }

p { margin: 0 0 1rem; }

/* ---- Layout helpers ---- */
.container { width: 100%; max-width: var(--maxw); margin-inline: auto; padding-inline: var(--gutter); }

.section { padding-block: clamp(2rem, 4vw, 3.2rem); }
.section--alt { background: var(--bg-alt); }

.section-head { max-width: 680px; margin-bottom: 1.5rem; }
.section-head .eyebrow {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 0.6rem;
}
.section-head p { color: var(--text-soft); font-size: 1.05rem; }

/* ---- Buttons ---- */
.btn {
  display: inline-flex;
  align-items: center;
  line-height: 1;
  gap: 0.5rem;
  padding: 0.75rem 1.4rem;
  border-radius: var(--radius-sm);
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition);
}
.btn--primary { background: var(--accent); color: #fff; }
.btn--primary:hover { background: var(--accent-strong); color: #fff; transform: translateY(-1px); }
.btn--ghost { background: transparent; color: var(--text); border-color: var(--border); }
.btn--ghost:hover { border-color: var(--accent); color: var(--accent); }
.btn img { width: 20px; height: 20px; flex-shrink: 0; display: block; }

/* ==========================================================================
   Header / Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: saturate(160%) blur(12px);
  border-bottom: 1px solid var(--border);
}
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 68px;
}
.nav__brand {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  font-family: var(--font-head);
  font-weight: 800;
  font-size: 1.15rem;
  letter-spacing: -0.02em;
  color: var(--text);
}
.nav__brand:hover { color: var(--text); }
.nav__mark {
  width: 34px; height: 34px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--accent), #4cb1c9);
  display: grid; place-items: center;
  color: #fff; font-weight: 800; font-size: 1rem;
}
.nav__links {
  display: flex;
  align-items: center;
  gap: 0.35rem;
  list-style: none;
  margin: 0; padding: 0;
}
.nav__links a {
  display: block;
  padding: 0.5rem 0.85rem;
  border-radius: var(--radius-sm);
  color: var(--text-soft);
  font-weight: 500;
  font-size: 0.95rem;
  transition: all var(--transition);
}
.nav__links a:hover { color: var(--text); background: var(--bg-alt); }
.nav__links a.is-active { color: var(--accent); background: var(--accent-soft); }

.nav__toggle {
  display: none;
  background: none; border: none; cursor: pointer;
  padding: 0.5rem; border-radius: var(--radius-sm);
}
.nav__toggle span,
.nav__toggle span::before,
.nav__toggle span::after {
  content: ""; display: block;
  width: 22px; height: 2px; background: var(--text);
  border-radius: 2px; transition: all var(--transition);
}
.nav__toggle span::before { transform: translateY(-7px); }
.nav__toggle span::after  { transform: translateY(5px); }
.nav.is-open .nav__toggle span { background: transparent; }
.nav.is-open .nav__toggle span::before { transform: rotate(45deg); }
.nav.is-open .nav__toggle span::after  { transform: rotate(-45deg); }

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  position: relative;
  background:
    radial-gradient(900px 400px at 75% -10%, rgba(76,177,201,0.18), transparent 60%),
    radial-gradient(700px 500px at 0% 110%, rgba(31,111,139,0.12), transparent 55%),
    var(--bg);
  overflow: hidden;
}
.hero__inner {
  display: grid;
  grid-template-columns: 1.1fr 0.9fr;
  gap: 3rem;
  align-items: center;
  padding-block: clamp(2.5rem, 5vw, 4rem);
}
.hero__eyebrow {
  font-size: 0.85rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 1rem;
}
.hero h1 { margin-bottom: 1rem; }
.hero__lead { font-size: 1.2rem; color: var(--text-soft); max-width: 46ch; margin-bottom: 2rem; }
.hero__actions { display: flex; gap: 0.8rem; flex-wrap: wrap; }

/* ==========================================================================
   Placeholder media (used until real images arrive)
   ========================================================================== */
.ph {
  position: relative;
  border-radius: var(--radius);
  background: linear-gradient(135deg, #dfe9ed, #f3f6f8);
  background-size: cover; background-position: center;
  display: grid; place-items: center;
  color: var(--accent-strong);
  font-weight: 600; font-size: 0.85rem;
  letter-spacing: 0.04em;
  overflow: hidden;
  border: 1px solid var(--border);
}
.ph::after {
  content: attr(data-label);
  opacity: 0.7;
  text-align: center;
  padding: 0 1rem;
}
.ph--hero { aspect-ratio: 4 / 3; box-shadow: var(--shadow-lg); }

/* tinted variants so cards don't all look identical */
.ph.t1 { background: linear-gradient(135deg, #dfe9ed, #eef4f6); }
.ph.t2 { background: linear-gradient(135deg, #e4e9f2, #f0f3f9); }
.ph.t3 { background: linear-gradient(135deg, #e9e4f2, #f4f0f9); }

/* Real images replacing .ph placeholders */
img.ph { object-fit: cover; }
.video-embed { position: relative; aspect-ratio: 16 / 9; background: #000; border-bottom: 1px solid var(--border); }
.video-embed iframe { position: absolute; inset: 0; width: 100%; height: 100%; border: 0; }

/* Home — about strip (images left, text right) */
.about-strip { display: grid; grid-template-columns: 1fr 1.1fr; gap: 3rem; align-items: center; }
.about-strip__text .eyebrow {
  display: inline-block; font-size: 0.8rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 0.6rem;
}
.about-strip__text p { color: var(--text-soft); font-size: 1.05rem; margin-top: 0.8rem; }
@media (max-width: 820px) {
  .about-strip { grid-template-columns: 1fr; gap: 1.8rem; }
  .about-strip__media { order: -1; }
}

/* Placeholder photo stack — mirror of .hero-stack, slides in from the left on scroll */
.about-stack { position: relative; width: 100%; aspect-ratio: 1 / 1.15; }
.about-stack .ph {
  position: absolute; width: 78%; aspect-ratio: 4 / 3;
  border-radius: 2px; border: 7px solid #fbf7ee; box-shadow: var(--shadow-lg);
  --tilt: 0deg;
}
body.theme-paper .about-stack .ph { border: 8px solid #fbf7ee; box-shadow: var(--paper-high); }
.about-stack .ph:nth-child(1) { top: 0; left: 0; --tilt: -6deg; z-index: 2; box-shadow: var(--paper-high, var(--shadow-lg)); }
.about-stack .ph:nth-child(2) { bottom: 0; right: 0; --tilt: 5deg; z-index: 1; box-shadow: var(--paper-mid, var(--shadow-lg)); }
.about-stack .ph { transform: rotate(var(--tilt)); }

html.js-anim .about-stack .ph {
  opacity: 0;
  transform: translateX(-160%) rotate(var(--tilt));
  transition: transform 750ms cubic-bezier(.22,.9,.32,1), opacity 750ms ease;
}
html.js-anim .about-stack.is-in .ph {
  opacity: 1;
  transform: rotate(var(--tilt));
}
html.js-anim .about-stack.is-in .ph:nth-child(1) { transition-delay: 80ms; }
html.js-anim .about-stack.is-in .ph:nth-child(2) { transition-delay: 260ms; }
@media (prefers-reduced-motion: reduce) {
  html.js-anim .about-stack .ph { transition: none; opacity: 1; transform: rotate(var(--tilt)); }
}

/* Home — people / group photo teaser */
.people-teaser { display: flex; flex-direction: column; }
.people-teaser__text { width: 100%; margin-top: 1.8rem; text-align: left; }
.people-teaser__text .eyebrow {
  display: inline-block; font-size: 0.8rem; font-weight: 600; letter-spacing: 0.12em;
  text-transform: uppercase; color: var(--accent); margin-bottom: 0.6rem;
}
.people-teaser__text p { color: var(--text-soft); font-size: 1.05rem; margin: 0.8rem 0 1.4rem; }
.people-teaser__media { width: 100%; }
.people-teaser__img {
  width: 100%; height: auto; border-radius: 0;
  display: block; box-shadow: var(--shadow-lg);
  border: 8px solid #fff;
  --tilt: -1deg;
  transform: rotate(var(--tilt));
}
body.theme-paper .people-teaser__img {
  border: 8px solid #fbf7ee; box-shadow: var(--paper-high);
}

/* Scroll-triggered reveal: slides up into view once the section is visible. */
html.js-anim .people-teaser__img {
  opacity: 0;
  transform: translateY(70px) rotate(var(--tilt));
  transition: transform 800ms cubic-bezier(.22,.9,.32,1), opacity 800ms ease;
}
html.js-anim .people-teaser__img.is-in-view {
  opacity: 1;
  transform: translateY(0) rotate(var(--tilt));
}
@media (prefers-reduced-motion: reduce) {
  html.js-anim .people-teaser__img { transition: none; opacity: 1; transform: rotate(var(--tilt)); }
}

/* Stacked photo gallery for hero */
.hero-stack {
  position: relative;
  width: 100%;
  aspect-ratio: 1 / 1.05;
}
.hero-stack__img {
  position: absolute;
  width: 60%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: 2px;
  display: block;
  border: 7px solid #fbf7ee;
  box-shadow: var(--shadow-lg);
  --rot: 0deg;
  transform: rotate(var(--rot));
  opacity: 1;
}
body.theme-paper .hero-stack__img { border: 8px solid #fbf7ee; }
/* front: hex pattern, top-right */
.hero-stack__img:nth-child(1) { top: 0; right: 0; --rot: 3deg; z-index: 3; box-shadow: var(--shadow-lg); transition-delay: 80ms; }
/* middle: swirl, center-left */
.hero-stack__img:nth-child(2) { top: 26%; left: 0; --rot: -9deg; z-index: 2; transition-delay: 230ms; }
/* back: fiber, bottom-right */
.hero-stack__img:nth-child(3) { bottom: 0; right: 8%; --rot: 18deg; z-index: 1; transition-delay: 380ms; }
body.theme-paper .hero-stack__img:nth-child(1) { box-shadow: var(--paper-high); }
body.theme-paper .hero-stack__img:nth-child(2) { box-shadow: var(--paper-mid); }
body.theme-paper .hero-stack__img:nth-child(3) { box-shadow: var(--paper-low); }

/* Slide-in only once JS confirms every image has actually finished loading —
   this avoids the image popping mid-animation while it's still decoding. */
html.js-anim .hero-stack__img {
  transform: translateX(160%) rotate(var(--rot));
  opacity: 0;
  transition: transform 750ms cubic-bezier(.22,.9,.32,1), opacity 750ms ease;
  transition-delay: 0ms;
}
html.js-anim .hero-stack.is-in .hero-stack__img {
  transform: rotate(var(--rot));
  opacity: 1;
}
html.js-anim .hero-stack.is-in .hero-stack__img:nth-child(1) { transition-delay: 80ms; }
html.js-anim .hero-stack.is-in .hero-stack__img:nth-child(2) { transition-delay: 230ms; }
html.js-anim .hero-stack.is-in .hero-stack__img:nth-child(3) { transition-delay: 380ms; }
@media (prefers-reduced-motion: reduce) {
  html.js-anim .hero-stack__img { transition: none; transform: rotate(var(--rot)); opacity: 1; }
}

/* ==========================================================================
   Cards / grids
   ========================================================================== */
.grid { display: grid; gap: 1.5rem; }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }

/* Recent Highlights — top row slides in from the left, bottom row from the right */
html.js-anim .grid--rows-reveal .card {
  opacity: 0;
  transition: transform 650ms cubic-bezier(.22,.9,.32,1), opacity 650ms ease;
}
html.js-anim .grid--rows-reveal .card:nth-child(-n+3) { transform: translateX(-90px); }
html.js-anim .grid--rows-reveal .card:nth-child(n+4)  { transform: translateX(90px); }
html.js-anim .grid--rows-reveal .card.is-in-view { opacity: 1; transform: translateX(0); }
@media (prefers-reduced-motion: reduce) {
  html.js-anim .grid--rows-reveal .card { transition: none; opacity: 1; transform: none; }
}
/* Cover section — featured slides in from the left, thumbnails rise from below */
html.js-anim .covers-split__featured img {
  opacity: 0; transform: rotate(-1.2deg) translateX(-70px);
  transition: transform 700ms cubic-bezier(.22,.9,.32,1), opacity 600ms ease;
}
html.js-anim .covers-split__featured.is-in img {
  opacity: 1; transform: rotate(-1.2deg) translateX(0);
}
html.js-anim .covers-split__thumbs .cover-gallery__item {
  opacity: 0; transform: translateY(50px);
  transition: transform 600ms cubic-bezier(.22,.9,.32,1), opacity 550ms ease;
}
html.js-anim .covers-split__thumbs.is-in .cover-gallery__item { opacity: 1; transform: translateY(0); }
html.js-anim .covers-split__thumbs.is-in .cover-gallery__item:nth-child(1) { transition-delay: 0ms; }
html.js-anim .covers-split__thumbs.is-in .cover-gallery__item:nth-child(2) { transition-delay: 80ms; }
html.js-anim .covers-split__thumbs.is-in .cover-gallery__item:nth-child(3) { transition-delay: 160ms; }
html.js-anim .covers-split__thumbs.is-in .cover-gallery__item:nth-child(4) { transition-delay: 240ms; }
html.js-anim .covers-split__thumbs.is-in .cover-gallery__item:nth-child(5) { transition-delay: 320ms; }
@media (prefers-reduced-motion: reduce) {
  html.js-anim .covers-split__featured img,
  html.js-anim .covers-split__thumbs .cover-gallery__item { transition: none; opacity: 1; transform: none; }
}

.grid--4 { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
.grid--4-center { display: flex; flex-wrap: wrap; gap: 1.5rem; justify-content: center; align-items: stretch; }
.grid--4-center > * { flex: 0 0 calc(25% - 1.125rem); min-width: 220px; max-width: 100%; display: flex; flex-direction: column; }
.grid--4-center .card__body.person { flex: 1; display: flex; flex-direction: column; }
.grid--4-center .card__body.person .member__links { margin-top: auto; padding-top: 0.5rem; }

.card {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  transition: transform var(--transition), box-shadow var(--transition);
}
.card:hover { transform: translateY(-3px); box-shadow: var(--shadow-lg); }
.card__body { padding: 1.4rem; display: flex; flex-direction: column; gap: 0.5rem; flex: 1; }
.card__body h3 { margin: 0; }
.card__body p { color: var(--text-soft); font-size: 0.96rem; margin: 0; }
.card__link {
  margin-top: auto; padding-top: 0.6rem;
  font-weight: 600; font-size: 0.9rem; color: var(--accent);
}
.card__link::after { content: " →"; }

/* People cards */
.person { text-align: center; }
.person h3 { font-size: 1.05rem; margin-bottom: 0.15rem; }
.person .role { color: var(--text-soft); font-size: 0.9rem; }
.person .meta { color: var(--accent); font-size: 0.82rem; margin-top: 0.3rem; }

/* ==========================================================================
   Interior pages: page hero, profile, people groups, publications, courses
   ========================================================================== */

/* Detailed research sections (alternating image / text + publications dropdown) */
.research-item {
  display: grid; grid-template-columns: 420px 1fr; gap: 2.6rem; align-items: start;
  padding-block: clamp(2rem, 5vw, 3.4rem); border-top: 1px solid var(--border);
}
.research-item:first-of-type { border-top: none; padding-top: 0; }
.research-item__media { position: sticky; top: 90px; }
.research-item__img {
  width: 100%; aspect-ratio: 4 / 3; object-fit: cover; border-radius: 0;
  display: block; box-shadow: var(--shadow-lg);
}
body.theme-paper .research-item__img { box-shadow: var(--paper-mid); border: 6px solid #fbf7ee; }
body.theme-paper .research-item:nth-of-type(3n+1) .research-item__img { transform: rotate(-1.4deg); box-shadow: var(--paper-high); }
body.theme-paper .research-item:nth-of-type(3n+2) .research-item__img { transform: rotate(1.1deg); box-shadow: var(--paper-low); }
body.theme-paper .research-item:nth-of-type(3n+3) .research-item__img { transform: rotate(-0.6deg); box-shadow: var(--paper-mid); }
.research-item h2 { margin-bottom: 0.8rem; }
.research-item__text p { color: var(--text-soft); }
.research-item:nth-of-type(even) { grid-template-columns: 1fr 420px; }
.research-item:nth-of-type(even) .research-item__media { grid-column: 2; grid-row: 1; }
.research-item:nth-of-type(even) .research-item__text { grid-column: 1; grid-row: 1; }

details.pub-dropdown {
  margin-top: 1.4rem; border: 1px solid var(--border);
  border-radius: var(--radius-sm); background: var(--bg); box-shadow: var(--paper-low, none);
}
details.pub-dropdown > summary {
  cursor: pointer; padding: 0.75rem 1rem; font-weight: 600; color: var(--accent);
  list-style: none; display: flex; justify-content: space-between; align-items: center;
}
details.pub-dropdown > summary::-webkit-details-marker { display: none; }
details.pub-dropdown > summary::after { content: "▾"; transition: transform var(--transition); }
details.pub-dropdown[open] > summary::after { transform: rotate(180deg); }
details.pub-dropdown .pub-list { padding: 0 0.8rem 0.7rem; }
details.pub-dropdown .pub-list li { margin-bottom: 0.4rem; }

@media (max-width: 820px) {
  .research-item { grid-template-columns: 1fr; gap: 1.2rem; }
  .research-item__media { position: static; }
}

/* Compact hero for interior pages */
.page-hero {
  background:
    radial-gradient(700px 300px at 80% -20%, var(--accent-soft), transparent 60%),
    var(--bg);
  padding-block: clamp(1.5rem, 3vw, 2.4rem);
  border-bottom: 1px solid var(--border);
}
/* On parallax pages, fade the hero's bottom edge into the texture instead of a hard border */
body.bg-parallax .page-hero,
body.bg-full .page-hero {
  background:
    radial-gradient(700px 300px at 80% -20%, var(--accent-soft), transparent 60%),
    linear-gradient(to bottom, var(--bg) 0, var(--bg) calc(100% - 72px), transparent 100%);
  border-bottom: none;
}
.page-hero .eyebrow {
  display: inline-block; font-size: 0.8rem; font-weight: 600;
  letter-spacing: 0.12em; text-transform: uppercase; color: var(--accent); margin-bottom: 0.6rem;
}
.page-hero p { color: var(--text-soft); font-size: 1.08rem; }
.hero-nowrap { white-space: nowrap; }
@media (max-width: 600px) { .hero-nowrap { white-space: normal; } }
.hero-line { max-width: none; white-space: nowrap; font-size: 1rem; color: var(--text-soft); }
@media (max-width: 700px) { .hero-line { white-space: normal; } }

/* PI profile block */
.profile {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 2.5rem;
  align-items: start;
}
.profile__photo { position: sticky; top: 90px; }
.profile h2 { margin-bottom: 0.2rem; }
.profile__sub { font-family: var(--font-head); font-weight: 700; font-size: 1.1rem; margin: 2rem 0 0.8rem; }
.profile__img { width: 100%; aspect-ratio: 3 / 4; object-fit: cover; border-radius: var(--radius); display: block; box-shadow: var(--shadow-lg); }
body.theme-paper .profile__img { box-shadow: var(--paper-high); border: 6px solid #fbf7ee; transform: rotate(-1.2deg); }
.profile__contact { margin-top: 1rem; font-size: 0.8rem; color: var(--text-soft); line-height: 1.8; }
.profile__contact a { color: var(--accent); text-decoration: none; }
.profile__contact a:hover { text-decoration: underline; }
.profile .role { color: var(--text-soft); font-weight: 500; font-size: 0.82rem; margin-bottom: 1rem; line-height: 1.6; }

/* Real headshot images replacing the avatar placeholders */
/* Circle container — holds the clip; img inside can scale freely */
.avatar-wrap { border-radius: 50%; overflow: hidden; border: 1px solid var(--border); background: var(--bg-alt); display: block; flex-shrink: 0; isolation: isolate; }
.avatar-img { width: 100%; height: 100%; object-fit: cover; object-position: var(--pos, center 20%); display: block; transform: scale(var(--zoom, 1)); transform-origin: var(--pos, center 20%); }
.person .avatar-wrap { width: 130px; height: 130px; margin: 0 auto 0.8rem; }

/* People group sub-sections */
.people-group { margin-top: 3rem; }
.people-group:first-of-type { margin-top: 0; }
.people-group__title {
  font-family: var(--font-head); font-weight: 700; font-size: 1.35rem;
  padding-bottom: 0.6rem; margin-bottom: 1.6rem;
  border-bottom: 2px solid var(--border);
}

/* Member cards (current students) — rectangular photo left, text right */
.grid--members { grid-template-columns: repeat(auto-fill, minmax(330px, 1fr)); }
.member .card__body { flex-direction: row; gap: 1rem; align-items: stretch; }
.member__photo {
  width: 100px; height: 128px; flex: 0 0 100px;
  object-fit: cover; border-radius: var(--radius-sm);
  border: 1px solid var(--border); background: var(--bg-alt);
}
.member__info { display: flex; flex-direction: column; gap: 0.35rem; flex: 1; min-width: 0; }
.member__info h3 { font-size: 1.05rem; margin: 0; }
.member__info .role, .member__info .detail { color: var(--text-soft); font-size: 0.82rem; line-height: 1.4; }
.member__links { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: auto; padding-top: 0.5rem; }
.member__links a {
  display: inline-flex; align-items: center; justify-content: center;
  font-size: 0.8rem; font-weight: 600; color: var(--accent);
  background: var(--accent-soft); padding: 0.3rem 0.5rem; border-radius: 999px;
  transition: all var(--transition);
}
/* Social icon buttons: uniform circle */
.member__links a[data-social] { width: 2rem; height: 2rem; padding: 0; }
.member__links a img { display: block; width: 18px; height: 18px; }
.member__links a:hover { background: var(--accent); color: #fff; }
.member__links a:hover img { filter: brightness(0) invert(1); }
.member__links a[data-social="linkedin"]:hover { background: #0A66C2; }
.member__links a[data-social="researchgate"]:hover { background: #00CCBB; }
.member__links a[data-social="scholar"]:hover { background: #4285f4; }
.member__links a[data-social="wikipedia"]:hover { background: #333; }
.alum .member__links { justify-content: center; padding-top: 0.4rem; }

/* Research page: section images slide in from the side they sit on.
   Direction is set via --tx so the even rule never overrides `transform`
   directly — avoiding the specificity clash with .is-in-view. */
html.js-anim .research-item__media {
  opacity: 0;
  --tx: -80px;
  --ty: 0px;
  transform: translate(var(--tx), var(--ty));
  transition: transform 750ms cubic-bezier(.22,.9,.32,1), opacity 700ms ease;
}
html.js-anim .research-item:nth-of-type(even) .research-item__media { --tx: 80px; }
html.js-anim .research-item__media.is-in-view { opacity: 1; transform: translate(0, 0); }
@media (max-width: 700px) {
  html.js-anim .research-item__media,
  html.js-anim .research-item:nth-of-type(even) .research-item__media { --tx: 0px; --ty: 40px; }
}
@media (prefers-reduced-motion: reduce) {
  html.js-anim .research-item__media { transition: none; opacity: 1; transform: none; }
}

/* People page: PI photo slides in from the left */
html.js-anim .profile__photo {
  opacity: 0;
  transform: translateX(-80px);
  transition: transform 750ms cubic-bezier(.22,.9,.32,1), opacity 700ms ease;
}
html.js-anim .profile__photo.is-in-view { opacity: 1; transform: translateX(0); }
@media (prefers-reduced-motion: reduce) {
  html.js-anim .profile__photo { transition: none; opacity: 1; transform: none; }
}

/* Collaborator cards slide up from bottom, staggered */
html.js-anim .grid--4-center .card {
  opacity: 0;
  transform: translateY(50px);
  transition: transform 600ms cubic-bezier(.22,.9,.32,1), opacity 600ms ease;
}
html.js-anim .grid--4-center .card.is-in-view { opacity: 1; transform: translateY(0); }
@media (prefers-reduced-motion: reduce) {
  html.js-anim .grid--4-center .card { transition: none; opacity: 1; transform: none; }
}

/* Alumni cards — circular photo, centered */
.grid--alumni { display: flex; flex-wrap: wrap; gap: 1.5rem; justify-content: center; }
.grid--alumni > * { flex: 0 0 190px; max-width: 190px; }

/* Host cards — fixed 4 across (4 top, 4 bottom) */
.grid--hosts { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 760px) { .grid--hosts { grid-template-columns: repeat(2, 1fr); } }

/* Location item — portrait image, alternating sides */
.location-item { grid-template-columns: 320px 1fr; }
.location-item--right { grid-template-columns: 1fr 320px; }
.location-item--right .research-item__media { grid-column: 2; grid-row: 1; }
.location-item--right .research-item__text   { grid-column: 1; grid-row: 1; }
.location-item .research-item__img { aspect-ratio: 5 / 6; }              /* portrait, constant */
.location-item .research-item__img.is-landscape { aspect-ratio: 4 / 3; } /* exception (2917) */
@media (max-width: 820px) {
  .location-item .research-item__media { max-width: 320px; }
}

/* Participant profile cards (compact, beside the location photo) */
.grid--participants { display: grid; gap: 0.7rem; margin-top: 1.1rem; }
.grid--participants.cols-3 { grid-template-columns: repeat(3, 1fr); }
.participant { text-align: center; }
.participant .card__body { padding: 0.85rem 0.6rem; min-height: 130px; justify-content: center; }
.participant h3 { font-size: 0.82rem; margin: 0; line-height: 1.2; }
.avatar-initials {
  width: 54px; height: 54px; margin: 0 auto 0.45rem; border-radius: 50%;
  display: grid; place-items: center; background: var(--accent-soft);
  color: var(--accent-strong); font-weight: 700; font-size: 1rem; font-family: var(--font-head);
}
body.theme-paper .avatar-initials { border: 4px solid #fbf7ee; box-shadow: var(--paper-low); }
@media (max-width: 560px) {
  .grid--participants.cols-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 820px) {
  .location-item--right { grid-template-columns: 1fr; }
  .location-item--right .research-item__media,
  .location-item--right .research-item__text { grid-column: auto; grid-row: auto; }
}
.alum { text-align: center; }
.alum .card__body { min-height: 260px; justify-content: flex-start; }
.alum.participant .card__body { min-height: 130px; padding: 0.85rem 0.6rem; justify-content: center; }
.alum .member__links { margin-top: auto; }
.alum .avatar-wrap { width: 92px; height: 92px; margin: 0 auto 0.6rem; }
.alum h3 { font-size: 0.98rem; margin: 0 0 0.15rem; }
.alum .detail { color: var(--text-soft); font-size: 0.82rem; }

/* Publications — hanging file-folder tabs */
.pub-tabs { position: relative; z-index: 1; }
.pub-tabs__list {
  display: flex; align-items: flex-end; gap: 0;
  list-style: none; margin: 0; padding: 0 0 0 0.4rem;
}
.pub-tabs__btn {
  position: relative; border: 1px solid var(--border); border-bottom: none;
  border-radius: 10px 10px 0 0;
  background: var(--bg-alt); color: var(--text-soft);
  font-family: var(--font-head); font-weight: 700; font-size: 1rem;
  padding: 0.7rem 1.5rem 0.6rem; margin-right: -1px;
  cursor: pointer; white-space: nowrap;
  transition: transform var(--transition), background var(--transition), color var(--transition), box-shadow var(--transition);
}
.pub-tabs__btn:nth-child(1) { transform: rotate(-1.1deg) translateY(4px); z-index: 1; }
.pub-tabs__btn:nth-child(2) { transform: rotate(0.7deg) translateY(6px); z-index: 2; }
.pub-tabs__btn:nth-child(3) { transform: rotate(-0.5deg) translateY(5px); z-index: 1; }
.pub-tabs__btn::before {
  content: ""; position: absolute; top: 0; left: 0; right: 0; height: 4px;
  border-radius: 10px 10px 0 0;
  background: var(--accent); opacity: 0; transition: opacity var(--transition);
}
.pub-tabs__btn:hover { color: var(--accent-strong); }
.pub-tabs__btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.pub-tabs__btn[aria-selected="true"] {
  background: #fbf7ee; color: var(--accent-strong);
  transform: translateY(0) rotate(0deg) !important;
  z-index: 3;
  box-shadow: var(--paper-mid, 0 6px 10px rgba(70,57,38,0.22));
}
.pub-tabs__btn[aria-selected="true"]::before { opacity: 1; }

.pub-search { margin: 0 0 1.4rem; }
.pub-search input {
  width: 100%; display: block;
  font-family: var(--font-sans); font-size: 0.92rem;
  padding: 0.6rem 0.9rem; border: 1px solid var(--border); border-radius: var(--radius-sm);
  background: #fbf7ee; color: var(--text);
  box-shadow: var(--paper-low, var(--shadow));
  transition: box-shadow var(--transition), border-color var(--transition);
}
.pub-search input:focus { outline: none; border-color: var(--accent); box-shadow: var(--paper-mid, var(--shadow)); }
.pub-search input::placeholder { color: var(--text-soft); }

.pub-panel {
  position: relative; z-index: 2;
  background: #fbf7ee; border: 1px solid var(--border); border-radius: 0 var(--radius) var(--radius) var(--radius);
  box-shadow: var(--paper-mid, var(--shadow));
  padding: 1.8rem 1.6rem 0.6rem; margin-top: -1px;
  animation: pub-fade-in 320ms ease both;
}
.pub-panel[hidden] { display: none; }
@keyframes pub-fade-in {
  from { opacity: 0; transform: translateY(4px); }
  to   { opacity: 1; transform: translateY(0); }
}
@media (max-width: 540px) {
  .pub-tabs__btn { font-size: 0.78rem; padding: 0.6rem 1rem 0.5rem; margin-right: -10px; }
}
@media (prefers-reduced-motion: reduce) {
  .pub-tabs__btn { transition: none; }
  .pub-panel { animation: none; }
}

/* Publications */
.pub-year {
  font-family: var(--font-head); font-weight: 800; font-size: 1.5rem;
  color: var(--accent); margin: 2.5rem 0 1rem;
  position: sticky; top: 76px; background: var(--bg); padding: 0.3rem 0;
}
.pub-list { list-style: none; margin: 0; padding: 0; }
.pub-list li {
  padding: 0.5rem 1rem; margin-bottom: 0.4rem;
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius-sm);
  box-shadow: var(--paper-low, var(--shadow));
  line-height: 1.4;
}
.pub-list .title { font-weight: 600; }
.pub-list .authors { color: var(--text-soft); font-size: 0.88rem; }
.pub-list .venue { font-size: 0.88rem; }
.pub-list .venue em { color: var(--text); font-style: italic; }
.pill {
  display: inline-block; font-size: 0.72rem; font-weight: 600; letter-spacing: 0.04em;
  text-transform: uppercase; color: var(--accent); background: var(--accent-soft);
  padding: 0.15rem 0.55rem; border-radius: 999px; margin-left: 0.4rem;
}

/* Course / timeline list */
.course-list { list-style: none; margin: 0; padding: 0; }
.course-list li { display: flex; gap: 1.2rem; padding: 0.7rem 0; border-bottom: 1px dashed var(--border); }
.course-list .when { flex: 0 0 130px; color: var(--accent); font-weight: 600; font-size: 0.9rem; }
.course-list .what .name { font-weight: 600; }
.course-list .what .where { color: var(--text-soft); font-size: 0.9rem; }

/* Year-grouped news — one paper card per year */
.year-block {
  background: var(--bg); border: 1px solid var(--border); border-radius: var(--radius);
  box-shadow: var(--paper-mid, var(--shadow));
  padding: 1rem 1.4rem 1.1rem; margin-bottom: 1.1rem;
}
.year-label {
  font-family: var(--font-head); font-weight: 800; font-size: 1.2rem; color: var(--accent);
  margin: 0 0 0.5rem; padding-bottom: 0.4rem; border-bottom: 1px solid var(--border);
}
.news-list { list-style: none; margin: 0; padding: 0; }
.news-list li { position: relative; padding: 0.55rem 0 0.55rem 1.25rem; border-bottom: 1px dashed var(--border); line-height: 1.45; }
.news-list li:last-child { border-bottom: none; padding-bottom: 0; }
.news-list li::before { content: "›"; position: absolute; left: 0; top: 0.55rem; color: var(--accent); font-weight: 700; }
.news-list .place { color: var(--text-soft); }
.news-list .sub { display: block; color: var(--text-soft); font-size: 0.9rem; margin-top: 0.15rem; }

/* IRES header fibers — square, overlapping paper cutouts */
.ires-fibers { position: relative; height: 390px; }
.ires-fibers img {
  position: absolute; width: 260px; height: auto;
  border-radius: 0; border: 1px solid var(--border); display: block;
}
.ires-fibers img:nth-child(1) { left: 10px;  top: 0px; transform: rotate(-1deg); z-index: 3; }
.ires-fibers img:nth-child(2) { left: 160px; top: 100px;    transform: rotate(1deg);  z-index: 2; }
.ires-fibers img:nth-child(3) { left: 60px;  top: 250px; transform: rotate(0deg); z-index: 1; }
body.theme-paper .ires-fibers img { border: 6px solid #fbf7ee; box-shadow: var(--paper-mid); }

.cover-gallery__item {
  display: block; width: 100%; padding: 0; border: none; background: none; cursor: pointer;
  border-radius: 2px;
}
.cover-gallery__item img {
  width: 100%; aspect-ratio: 3 / 4; object-fit: cover; display: block;
  border: 1px solid var(--border); border-radius: 2px; transition: transform var(--transition), box-shadow var(--transition);
}
body.theme-paper .cover-gallery__item img { border: 6px solid #fbf7ee; box-shadow: var(--paper-low); }
body.theme-paper .cover-gallery__item:nth-child(3n+1) img { transform: rotate(-1.4deg); }
body.theme-paper .cover-gallery__item:nth-child(3n+2) img { transform: rotate(1deg); }
body.theme-paper .cover-gallery__item:nth-child(3n)   img { transform: rotate(-0.5deg); }
.cover-gallery__item:hover img, .cover-gallery__item:focus-visible img { transform: rotate(0deg) scale(1.05); box-shadow: var(--paper-mid); }
.cover-gallery__item:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.covers-split { display: grid; grid-template-columns: auto 1fr; gap: 2.5rem; align-items: start; margin-top: 1.5rem; }
.covers-split__featured img { display: block; border: 8px solid #fbf7ee; box-shadow: var(--paper-mid); transform: rotate(-1.2deg); }
.covers-split__thumbs { display: grid; grid-template-columns: repeat(6, 1fr); gap: 1.2rem; }
.covers-split__thumbs .cover-gallery__item { grid-column: span 2; }
.covers-split__thumbs .cover-gallery__item:nth-child(1) { grid-column: 2 / span 2; }
@media (max-width: 720px) { .covers-split { grid-template-columns: 1fr; } .covers-split__featured img { max-width: 200px; } }

@media (max-width: 720px) {
  .profile { grid-template-columns: 1fr; gap: 1.5rem; }
  .profile__photo { position: static; max-width: 220px; }
  .course-list li { flex-direction: column; gap: 0.2rem; }
  .pub-year { position: static; }
}

/* Clickable profile cards + modal */
.profile-card { cursor: pointer; }
.profile-card:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.modal[hidden] { display: none; }
.modal { position: fixed; inset: 0; z-index: 100; display: grid; place-items: center; padding: 1.5rem; }
.modal__backdrop { position: absolute; inset: 0; background: rgba(15, 20, 30, 0.55); }
.modal__panel {
  position: relative; background: var(--bg); border: 1px solid var(--border);
  border-radius: var(--radius); max-width: 540px; width: 100%; padding: 1.8rem;
  box-shadow: var(--shadow-lg); max-height: 90vh; overflow: visible;
}
body.theme-paper .modal__panel { box-shadow: var(--paper-high); }
.modal__panel--image {
  max-width: min(92vw, 1100px); width: auto; padding: 0.6rem;
  background: #fbf7ee; display: inline-block;
}
.modal__panel--image img {
  display: block; max-width: calc(92vw - 1.2rem); max-height: 88vh;
  width: auto; height: auto; border-radius: 2px;
}
.modal__close { position: absolute; top: 0.5rem; right: 0.8rem; background: none; border: none; font-size: 1.7rem; line-height: 1; cursor: pointer; color: var(--text-soft); }
.modal__close:hover { color: var(--text); }
.modal__head { display: flex; align-items: center; gap: 1rem; margin-bottom: 1rem; text-align: left; }
.modal__head .avatar-wrap, .modal__head .avatar-initials { width: 84px; height: 84px; margin: 0; flex: 0 0 84px; }
.modal__head h3 { margin: 0 0 0.15rem; font-size: 1.25rem; }
.modal__head .detail { color: var(--text-soft); font-size: 0.9rem; }
.modal__body {
  color: var(--text); line-height: 1.6; text-align: left; font-size: 0.92rem;
  font-style: italic; position: relative; padding: 0.3rem 0.9rem;
}
.modal__body::before, .modal__body::after {
  font-family: var(--font-head); font-style: normal; font-weight: 800;
  font-size: 2.8rem; color: var(--accent); opacity: 0.22; line-height: 1;
  position: absolute; pointer-events: none;
}
.modal__body::before { content: "“"; top: -0.7rem; left: -0.5rem; }
.modal__body::after { content: "”"; bottom: -1.7rem; right: -0.3rem; }

/* ==========================================================================
   Footer
   ========================================================================== */
.site-footer {
  background: var(--bg-deep);
  color: #c7d0dd;
  padding-block: 3.5rem 2rem;
}
.site-footer a { color: #c7d0dd; }
.site-footer a:hover { color: #fff; }
.footer__grid {
  display: grid;
  grid-template-columns: 1.4fr 1fr 1fr;
  gap: 2.5rem;
  margin-bottom: 2.5rem;
}
.footer__brand { font-family: var(--font-head); font-weight: 800; font-size: 1.3rem; color: #fff; margin-bottom: 0.6rem; }
.footer h4 { color: #fff; font-size: 0.95rem; margin-bottom: 0.8rem; }
.footer ul { list-style: none; margin: 0; padding: 0; }
.footer li { margin-bottom: 0.5rem; font-size: 0.95rem; }
.footer__bottom {
  border-top: 1px solid rgba(255,255,255,0.12);
  padding-top: 1.5rem;
  font-size: 0.85rem; color: #8893a4;
  display: flex; justify-content: space-between; gap: 1rem; flex-wrap: wrap;
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 860px) {
  .hero__inner { grid-template-columns: 1fr; gap: 2rem; }
  .hero__media { order: -1; }
  .footer__grid { grid-template-columns: 1fr; gap: 1.8rem; }
}

@media (max-width: 768px) {
  .nav__toggle { display: block; }
  .nav__links {
    position: absolute;
    top: 68px; left: 0; right: 0;
    border-radius: 0 0 var(--radius) var(--radius);
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: rgba(255, 255, 255, 0.85);
    backdrop-filter: saturate(160%) blur(12px);
    -webkit-backdrop-filter: saturate(160%) blur(12px);
    border-bottom: 1px solid var(--border);
    box-shadow: var(--shadow);
    padding: 0.5rem var(--gutter) 1rem;
    max-height: 0;
    overflow: hidden;
    transition: max-height 240ms ease, padding 240ms ease;
    padding-block: 0;
  }
  .nav.is-open .nav__links { max-height: 70vh; padding-block: 0.5rem 1rem; }
  .nav__links a { padding: 0.8rem 0.6rem; border-radius: var(--radius-sm); }
}

/* Back-to-top button (publications page) */
.back-to-top {
  position: fixed;
  right: 1.5rem;
  bottom: 1.5rem;
  z-index: 60;
  width: 44px;
  height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  cursor: pointer;
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transform: translateY(8px);
  transition: opacity 200ms ease, transform 200ms ease, background 160ms ease;
}
.back-to-top.is-visible { opacity: 1; transform: translateY(0); }
.back-to-top:hover { background: var(--accent-strong); }
.back-to-top:focus-visible { outline: 2px solid var(--accent-strong); outline-offset: 2px; }
@media (max-width: 640px) {
  .back-to-top { right: 1rem; bottom: 1rem; }
}