/* ==========================================================================
   GLOW Lab — Generative Learning of Worlds
   Design system + site styles (light theme with glow accents)
   ========================================================================== */

:root {
  --bg: #f8fafd;
  --bg-elev: #eef2f9;
  --card: #ffffff;
  --card-hover: #f5f8ff;
  --border: #e3e8f2;
  --border-strong: #ccd5e5;

  --text: #101828;
  --text-muted: #51607a;
  --text-faint: #7f8ba3;

  --glow-a: #0d9488; /* teal   */
  --glow-b: #4f46e5; /* indigo */
  --glow-c: #9333ea; /* violet */

  --gradient: linear-gradient(100deg, var(--glow-a) 0%, var(--glow-b) 48%, var(--glow-c) 100%);

  --shadow-sm: 0 1px 2px rgba(16, 24, 40, 0.05);
  --shadow-md: 0 6px 20px -4px rgba(16, 24, 40, 0.1);

  --font-display: "Sora", "Inter", system-ui, sans-serif;
  --font-body: "Inter", system-ui, -apple-system, sans-serif;

  --container: 1120px;
  --radius: 14px;
  --header-h: 72px;
}

/* ---------- Reset / base ---------- */

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16.5px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

a { color: inherit; text-decoration: none; }

::selection { background: rgba(79, 70, 229, 0.18); }

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 12px;
  z-index: 100;
  background: var(--card);
  border: 1px solid var(--border-strong);
  padding: 10px 16px;
  border-radius: 8px;
}
.skip-link:focus { left: 12px; }

:focus-visible {
  outline: 2px solid var(--glow-b);
  outline-offset: 3px;
  border-radius: 4px;
}

/* ---------- Typography ---------- */

h1, h2, h3, h4 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: 1.15;
  margin: 0 0 0.5em;
  letter-spacing: -0.015em;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 18px;
}
.eyebrow::before {
  content: "";
  width: 26px;
  height: 2px;
  border-radius: 2px;
  background: var(--gradient);
}

.section-title {
  font-size: clamp(28px, 4vw, 40px);
  margin-bottom: 14px;
}

.section-lead {
  color: var(--text-muted);
  font-size: 18px;
  max-width: 640px;
  margin: 0 0 40px;
}

.text-gradient {
  background: var(--gradient);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* ---------- Header ---------- */

.site-header {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 50;
  height: var(--header-h);
  display: flex;
  align-items: center;
  transition: background 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
  border-bottom: 1px solid transparent;
}
.site-header.scrolled {
  background: rgba(248, 250, 253, 0.85);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom-color: var(--border);
}

.nav {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 19px;
  letter-spacing: 0.02em;
}
.brand-mark {
  width: 26px;
  height: 26px;
  border-radius: 50%;
  background:
    radial-gradient(circle at 32% 30%, rgba(255, 255, 255, 0.95) 0%, rgba(255, 255, 255, 0) 34%),
    conic-gradient(from 210deg, #2dd4bf, #6366f1, #c084fc, #2dd4bf);
  box-shadow:
    0 0 12px rgba(99, 102, 241, 0.4),
    0 0 28px rgba(192, 132, 252, 0.22);
  flex: none;
}
.brand-sub {
  color: var(--text-muted);
  font-weight: 500;
  margin-left: 7px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
  list-style: none;
  margin: 0;
  padding: 0;
}
.nav-links a:not(.btn) {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 500;
  color: var(--text-muted);
  transition: color 0.2s ease, background 0.2s ease;
}
.nav-links a:not(.btn):hover { color: var(--text); background: var(--card-hover); }
.nav-links a:not(.btn)[aria-current="page"] { color: var(--text); }

.nav-cta {
  margin-left: 10px;
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border-strong);
  border-radius: 8px;
  width: 42px;
  height: 42px;
  cursor: pointer;
  padding: 0;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 5px;
}
.nav-toggle span {
  display: block;
  width: 18px;
  height: 2px;
  border-radius: 2px;
  background: var(--text);
  transition: transform 0.25s ease, opacity 0.25s ease;
}
.nav-toggle[aria-expanded="true"] span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
.nav-toggle[aria-expanded="true"] span:nth-child(2) { opacity: 0; }
.nav-toggle[aria-expanded="true"] span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 9px;
  padding: 12px 22px;
  border-radius: 999px;
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.01em;
  cursor: pointer;
  border: 1px solid transparent;
  transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease, border-color 0.2s ease;
}
.btn-primary {
  color: #ffffff;
  background: var(--gradient);
  box-shadow: 0 4px 16px rgba(79, 70, 229, 0.3);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 26px rgba(79, 70, 229, 0.4);
}
.btn-ghost {
  color: var(--text);
  border-color: var(--border-strong);
  background: var(--card);
  box-shadow: var(--shadow-sm);
}
.btn-ghost:hover {
  border-color: #aab7cf;
  background: var(--card-hover);
  transform: translateY(-2px);
}
.btn-sm { padding: 9px 18px; font-size: 14px; }

.btn .icon { flex: none; opacity: 0.8; }

.btn .arrow { transition: transform 0.2s ease; }
.btn:hover .arrow { transform: translateX(3px); }

/* ---------- Hero ---------- */

.hero {
  position: relative;
  overflow: hidden;
  padding: calc(var(--header-h) + 56px) 0 88px;
  background:
    radial-gradient(ellipse 55% 30% at 76% 16%, rgba(99, 102, 241, 0.07), transparent 65%),
    radial-gradient(ellipse 50% 26% at 20% 8%, rgba(45, 212, 191, 0.06), transparent 65%),
    var(--bg);
}

#world-canvas {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  width: 100%;
  height: 560px;
  z-index: 0;
}

.hero::after {
  /* bottom fade into page background */
  content: "";
  position: absolute;
  inset: auto 0 0 0;
  height: 140px;
  background: linear-gradient(to bottom, transparent, var(--bg));
  z-index: 1;
  pointer-events: none;
}

.hero-inner {
  position: relative;
  z-index: 2;
  max-width: 780px;
  margin-bottom: 72px;
}

.hero h1 {
  font-size: clamp(38px, 5.6vw, 62px);
  font-weight: 700;
  letter-spacing: -0.03em;
  margin: 0;
}

.hero-at {
  font-size: 0.58em;
  font-weight: 600;
  color: var(--text-muted);
  letter-spacing: -0.015em;
}

/* ---------- Sections ---------- */

.section { padding: 96px 0; }
.section-alt {
  background: var(--bg-elev);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

/* subpage hero */
.page-head {
  padding: calc(var(--header-h) + 72px) 0 56px;
  position: relative;
  overflow: hidden;
}
.page-head::before {
  content: "";
  position: absolute;
  top: -320px;
  left: 50%;
  transform: translateX(-50%);
  width: 900px;
  height: 520px;
  background: radial-gradient(ellipse at center,
    rgba(99, 102, 241, 0.09) 0%,
    rgba(147, 51, 234, 0.05) 45%,
    transparent 70%);
  pointer-events: none;
}
.page-head h1 { font-size: clamp(34px, 5vw, 52px); }
.page-head p { color: var(--text-muted); font-size: 18px; max-width: 640px; margin: 0; }

/* ---------- Research pillars ---------- */

.pillars {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.pillar {
  position: relative;
  padding: 30px 28px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
  overflow: hidden;
}
.pillar::before {
  content: "";
  position: absolute;
  inset: 0 0 auto 0;
  height: 2px;
  background: var(--gradient);
  opacity: 0;
  transition: opacity 0.25s ease;
}
.pillar:hover {
  transform: translateY(-4px);
  border-color: var(--border-strong);
  box-shadow: var(--shadow-md);
}
.pillar:hover::before { opacity: 1; }

.pillar-icon {
  width: 46px;
  height: 46px;
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
  border: 1px solid var(--border);
  background: var(--bg);
}
.pillar-icon svg { stroke: url(#icon-gradient); }

.pillar h3 { font-size: 20px; margin-bottom: 10px; }
.pillar p { color: var(--text-muted); font-size: 15.5px; margin: 0; }

/* ---------- News ---------- */

.news-list {
  list-style: none;
  margin: 0;
  padding: 0;
  border-left: 1px solid var(--border-strong);
}
.news-item {
  position: relative;
  padding: 0 0 30px 32px;
}
.news-item:last-child { padding-bottom: 0; }
.news-item::before {
  content: "";
  position: absolute;
  left: -5px;
  top: 7px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--glow-b);
  box-shadow: 0 0 8px rgba(79, 70, 229, 0.55);
}
.news-date {
  font-family: var(--font-display);
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-faint);
  display: block;
  margin-bottom: 4px;
}
.news-item p { margin: 0; color: var(--text); }
.news-item a { border-bottom: 1px solid var(--border-strong); transition: border-color 0.2s, color 0.2s; }
.news-item a:hover { border-color: var(--glow-b); color: var(--glow-b); }

/* ---------- Publications ---------- */

.pub-year {
  font-family: var(--font-display);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.14em;
  color: var(--text-faint);
  margin: 52px 0 18px;
  display: flex;
  align-items: center;
  gap: 16px;
}
.pub-year::after {
  content: "";
  flex: 1;
  height: 1px;
  background: var(--border);
}
.pub-year:first-of-type { margin-top: 8px; }

.pub-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 14px; }

.pub {
  padding: 22px 24px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  box-shadow: var(--shadow-sm);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}
.pub:hover { border-color: var(--border-strong); box-shadow: var(--shadow-md); }

.pub-title {
  font-family: var(--font-display);
  font-size: 17px;
  font-weight: 600;
  line-height: 1.35;
  margin: 0 0 6px;
}
.pub-title a { transition: color 0.2s ease; }
.pub-title a:hover { color: var(--glow-b); }

.pub-authors {
  font-size: 14.5px;
  color: var(--text-muted);
  margin: 0 0 12px;
}
.pub-authors .me { color: var(--text); font-weight: 600; }

.pub-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}
.venue {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid rgba(79, 70, 229, 0.3);
  color: #4341b5;
  background: rgba(79, 70, 229, 0.07);
}
.award {
  font-size: 12.5px;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 4px 11px;
  border-radius: 999px;
  border: 1px solid rgba(13, 148, 136, 0.35);
  color: #0b7268;
  background: rgba(13, 148, 136, 0.07);
}
.pub-links {
  margin-left: auto;
  display: flex;
  gap: 14px;
}
.pub-links a {
  font-size: 13.5px;
  font-weight: 500;
  color: var(--text-muted);
  border-bottom: 1px solid transparent;
  transition: color 0.2s ease;
}
.pub-links a:hover { color: var(--glow-b); }

/* ---------- People ---------- */

.pi-card {
  display: grid;
  grid-template-columns: 190px 1fr;
  gap: 40px;
  align-items: start;
}

.pi-photo-wrap {
  position: relative;
  border-radius: var(--radius);
  width: 150px;
}
.pi-photo-wrap::before {
  content: "";
  position: absolute;
  inset: -1px;
  border-radius: calc(var(--radius) + 1px);
  background: var(--gradient);
  opacity: 0.3;
  filter: blur(14px);
  z-index: 0;
}
.pi-photo {
  position: relative;
  z-index: 1;
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--border-strong);
}

.pi-name { font-size: 25px; margin-bottom: 4px; }
.pi-name-kr { font-weight: 500; color: var(--text-muted); font-size: 0.85em; }
.pi-role {
  color: var(--text-muted);
  font-size: 16px;
  margin: 0 0 20px;
}
.pi-bio p { color: var(--text-muted); margin: 0 0 14px; }
.pi-bio strong { color: var(--text); font-weight: 600; }

.pi-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 24px;
}

.pi-card > div:first-child {
  align-self: stretch;
  display: flex;
  flex-direction: column;
}

.pi-facts {
  margin-top: 18px;
  flex: 1;
  display: flex;
  flex-direction: column;
}
.fact-list {
  list-style: none;
  margin: 0;
  padding: 0;
  flex: 1;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 10px;
}
.fact-list li {
  display: grid;
  gap: 1px;
  padding-left: 12px;
  border-left: 2px solid var(--border-strong);
}
.fact-when {
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--text-faint);
}
.fact-title {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--text);
  line-height: 1.35;
}
.fact-sub {
  font-size: 13px;
  color: var(--text-muted);
}

.people-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.person-card {
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card);
  box-shadow: var(--shadow-sm);
  padding: 30px 22px 26px;
  text-align: center;
}

.person-avatar {
  width: 84px;
  height: 84px;
  border-radius: 50%;
  margin: 0 auto 16px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: 1px solid var(--border);
  background: linear-gradient(135deg, #e3f4f1, #e9e9fb 50%, #f2e8fb);
  color: var(--text-faint);
}

.person-avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  border-radius: 50%;
}

.person-name { font-size: 17px; margin: 0 0 3px; }
.person-role { font-size: 14px; color: var(--text-muted); margin: 0; }

.person-card.person-join {
  border-style: dashed;
  border-color: var(--border-strong);
  background: rgba(255, 255, 255, 0.6);
  box-shadow: none;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
}
.person-join p {
  font-size: 14px;
  color: var(--text-muted);
  margin: 0 0 16px;
}

/* ---------- Join ---------- */

.join-grid {
  display: grid;
  grid-template-columns: 1.15fr 1fr;
  gap: 26px;
  align-items: start;
}

.join-card {
  padding: 32px 30px;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--card);
  box-shadow: var(--shadow-sm);
}
.join-card h3 { font-size: 21px; margin-bottom: 14px; }
.join-card p, .join-card li { color: var(--text-muted); }
.join-card p { margin: 0 0 14px; }
.join-card p:last-child { margin-bottom: 0; }

.checklist {
  list-style: none;
  margin: 0 0 8px;
  padding: 0;
  display: grid;
  gap: 13px;
}
.checklist li {
  position: relative;
  padding-left: 34px;
}
.checklist li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 3px;
  width: 20px;
  height: 20px;
  border-radius: 50%;
  border: 1px solid rgba(13, 148, 136, 0.45);
  background:
    radial-gradient(circle at center, rgba(13, 148, 136, 0.1), transparent 70%);
}
.checklist li::after {
  content: "";
  position: absolute;
  left: 6px;
  top: 8px;
  width: 8px;
  height: 5px;
  border-left: 2px solid var(--glow-a);
  border-bottom: 2px solid var(--glow-a);
  transform: rotate(-45deg);
}
.checklist strong { color: var(--text); }

/* CTA banner */
.cta-banner {
  position: relative;
  border-radius: 20px;
  border: 1px solid var(--border);
  padding: 64px 48px;
  text-align: center;
  overflow: hidden;
  background: var(--card);
  box-shadow: var(--shadow-sm);
}
.cta-banner::before {
  content: "";
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 90% at 20% 110%, rgba(45, 212, 191, 0.08), transparent 60%),
    radial-gradient(ellipse 70% 90% at 80% -10%, rgba(192, 132, 252, 0.08), transparent 60%);
  pointer-events: none;
}
.cta-banner > * { position: relative; }
.cta-banner h2 { font-size: clamp(26px, 3.6vw, 38px); margin-bottom: 14px; }
.cta-banner p {
  color: var(--text-muted);
  max-width: 560px;
  margin: 0 auto 30px;
  font-size: 17px;
}

/* compact variant — quieter closing note */
.cta-compact {
  padding: 34px 32px;
  border-radius: var(--radius);
}
.cta-compact::before { content: none; }
.cta-compact h2 { font-size: 22px; margin-bottom: 8px; }
.cta-compact p { font-size: 15.5px; margin-bottom: 20px; }

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--border);
  padding: 32px 0 26px;
  background: var(--bg-elev);
}
.footer-compact {
  display: flex;
  justify-content: space-between;
  align-items: flex-start;
  gap: 16px 40px;
  flex-wrap: wrap;
  margin-bottom: 22px;
}
.footer-address {
  color: var(--text-faint);
  font-size: 13.5px;
  line-height: 1.6;
  margin: 0;
  text-align: right;
}

.footer-bottom {
  border-top: 1px solid var(--border);
  padding-top: 20px;
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
  color: var(--text-faint);
  font-size: 13.5px;
}

/* ---------- Reveal on scroll ---------- */

.reveal {
  opacity: 0;
  transform: translateY(22px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}
.reveal.visible {
  opacity: 1;
  transform: none;
}
.reveal-delay-1 { transition-delay: 0.1s; }
.reveal-delay-2 { transition-delay: 0.2s; }

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal { opacity: 1; transform: none; transition: none; }
  * { transition-duration: 0.01ms !important; }
}

/* ---------- Responsive ---------- */

@media (max-width: 980px) {
  .pillars { grid-template-columns: 1fr; }
  .join-grid { grid-template-columns: 1fr; }
  .pi-card { grid-template-columns: 190px 1fr; gap: 32px; }
  .people-grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .section { padding: 68px 0; }

  .nav-toggle { display: flex; }
  .nav-links {
    position: fixed;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 4px;
    padding: 16px 20px 24px;
    background: rgba(248, 250, 253, 0.98);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    transform: translateY(-12px);
    opacity: 0;
    visibility: hidden;
    transition: transform 0.25s ease, opacity 0.25s ease, visibility 0.25s;
  }
  .nav-links.open {
    transform: none;
    opacity: 1;
    visibility: visible;
  }
  .nav-links a:not(.btn) { padding: 13px 14px; font-size: 16px; }
  .nav-cta { margin: 10px 0 0; }

  .pi-card { grid-template-columns: 1fr; }
  .pi-photo-wrap { max-width: 210px; }
  .people-grid { grid-template-columns: 1fr; }

  .pub { padding: 18px; }
  .pub-links { margin-left: 0; width: 100%; }

  .cta-banner { padding: 48px 24px; }
  .cta-compact { padding: 30px 22px; }
  .footer-compact { flex-direction: column; }
  .footer-address { text-align: left; }
}