:root {
  --navy: #0b2540;
  --navy-2: #12355b;
  --teal: #0e8a9c;
  --teal-light: #e6f4f6;
  --sky: #5cc6d6;
  --ink: #1b2430;
  --muted: #5b6876;
  --line: #e3e8ee;
  --bg: #ffffff;
  --bg-soft: #f6f8fb;
  --radius: 12px;
  --max: 1120px;
  --shadow: 0 1px 2px rgba(11, 37, 64, .06), 0 6px 20px rgba(11, 37, 64, .06);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Pretendard", -apple-system, BlinkMacSystemFont, "Segoe UI", "Malgun Gothic", sans-serif;
  color: var(--ink);
  background: var(--bg);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
a { color: var(--teal); text-decoration: none; }
a:hover { text-decoration: underline; }
img { max-width: 100%; display: block; }
h1, h2, h3, h4 { color: var(--navy); line-height: 1.3; margin: 0 0 .6em; letter-spacing: -0.01em; }
h1 { font-size: clamp(1.9rem, 4vw, 2.8rem); }
h2 { font-size: clamp(1.4rem, 2.6vw, 1.85rem); }
h3 { font-size: 1.15rem; }
p { margin: 0 0 1em; }

.container { max-width: var(--max); margin: 0 auto; padding: 0 20px; }
section { padding: 64px 0; }
.section-soft { background: var(--bg-soft); }
.eyebrow {
  display: inline-block; font-size: .78rem; font-weight: 700; letter-spacing: .14em;
  text-transform: uppercase; color: var(--teal); margin-bottom: .6em;
}
.lead { font-size: 1.1rem; color: var(--muted); max-width: 720px; }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .92); backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 68px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--navy); }
.brand:hover { text-decoration: none; }
.brand img { width: 36px; height: 36px; }
.brand-text { display: flex; flex-direction: column; line-height: 1.15; }
.brand-text strong { font-size: 1.05rem; letter-spacing: .02em; }
.brand-text span { font-size: .72rem; color: var(--muted); }
.nav-links { display: flex; gap: 4px; list-style: none; margin: 0 0 0 auto; padding: 0; }
.nav-right { display: flex; align-items: center; gap: 4px; }
/* Language switch (English | 한국어) */
.lang-switch { display: flex; align-items: center; gap: 2px; margin-left: 10px; padding-left: 12px; border-left: 1px solid var(--line); font-size: .82rem; white-space: nowrap; }
.lang-switch a { padding: 4px 6px; border-radius: 6px; color: var(--muted); font-weight: 600; }
.lang-switch a:hover { color: var(--navy); background: var(--bg-soft); text-decoration: none; }
.lang-switch a.on { color: var(--teal); }
.lang-switch span { color: var(--line); }
/* Blocks shown in one language only (the <head> script sets <html lang> early) */
html[lang="ko"] [data-only="en"], html:not([lang="ko"]) [data-only="ko"] { display: none !important; }
.name-sub { margin: -2px 0 4px; font-size: .85rem; color: var(--muted); }
.nav-links a {
  display: block; padding: 8px 14px; border-radius: 8px; color: var(--ink);
  font-weight: 500; font-size: .95rem;
}
.nav-links a:hover { background: var(--bg-soft); text-decoration: none; }
.nav-links a.active { color: var(--teal); background: var(--teal-light); }
.nav-toggle {
  display: none; background: none; border: 0; padding: 8px; cursor: pointer; color: var(--navy);
}
@media (max-width: 1120px) { /* 9 menu items + language switch: use the menu button before they wrap */
  .nav-toggle { display: block; }
  .lang-switch { border-left: 0; padding-left: 0; margin-left: 0; }
  .nav-links {
    display: none; position: absolute; top: 68px; left: 0; right: 0;
    flex-direction: column; background: #fff; border-bottom: 1px solid var(--line);
    padding: 8px 16px 16px;
  }
  .nav-links.open { display: flex; }
}

/* ---------- Hero ---------- */
.hero {
  position: relative; overflow: hidden; color: #fff;
  background: radial-gradient(1200px 500px at 80% -10%, #1a5a86 0%, transparent 60%),
              linear-gradient(160deg, var(--navy) 0%, var(--navy-2) 100%);
  padding: 96px 0 120px;
}
.hero h1 { color: #fff; max-width: 820px; }
.hero .ko { font-size: 1.25rem; color: var(--sky); font-weight: 600; margin-bottom: 1.2em; }
.hero p { color: rgba(255, 255, 255, .82); max-width: 680px; font-size: 1.08rem; }
.hero .eyebrow { color: var(--sky); }
.hero-waves { position: absolute; left: 0; right: 0; bottom: -2px; width: 100%; height: 90px; }
.btn-row { display: flex; gap: 12px; flex-wrap: wrap; margin-top: 28px; }
.btn {
  display: inline-block; padding: 12px 22px; border-radius: 999px; font-weight: 600; font-size: .95rem;
  border: 1px solid transparent; transition: transform .15s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); }
.btn-primary { background: var(--sky); color: var(--navy); }
.btn-ghost { border-color: rgba(255, 255, 255, .4); color: #fff; }
.btn-outline { border-color: var(--teal); color: var(--teal); }

.page-hero {
  background: linear-gradient(160deg, var(--navy) 0%, var(--navy-2) 100%);
  color: #fff; padding: 56px 0 48px;
}
.page-hero h1 { color: #fff; margin-bottom: .2em; }
.page-hero p { color: rgba(255, 255, 255, .78); margin: 0; }
.page-hero .eyebrow { color: var(--sky); }

/* ---------- Cards / grids ---------- */
.grid { display: grid; gap: 20px; }
.grid-2 { grid-template-columns: repeat(2, 1fr); }
.grid-3 { grid-template-columns: repeat(3, 1fr); }
.grid-4 { grid-template-columns: repeat(4, 1fr); }
@media (max-width: 960px) { .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); } }
@media (max-width: 620px) { .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; } }

.card {
  background: #fff; border: 1px solid var(--line); border-radius: var(--radius);
  padding: 24px; box-shadow: var(--shadow);
}
.card h3 { margin-bottom: .4em; }
.card p { color: var(--muted); font-size: .95rem; }
.icon {
  width: 44px; height: 44px; border-radius: 10px; background: var(--teal-light); color: var(--teal);
  display: grid; place-items: center; margin-bottom: 14px;
}
.icon svg { width: 24px; height: 24px; }
.tags { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }
.tag {
  font-size: .78rem; padding: 3px 10px; border-radius: 999px; background: var(--bg-soft);
  color: var(--navy-2); border: 1px solid var(--line);
}

.stats { display: grid; grid-template-columns: repeat(4, 1fr); gap: 16px; }
@media (max-width: 760px) { .stats { grid-template-columns: repeat(2, 1fr); } }
.stat { text-align: center; padding: 20px 10px; }
.stat strong { display: block; font-size: 2.1rem; color: var(--navy); line-height: 1.1; }
.stat span { color: var(--muted); font-size: .9rem; }

.section-head { display: flex; justify-content: space-between; align-items: end; gap: 16px; margin-bottom: 28px; flex-wrap: wrap; }
.section-head h2 { margin: 0; }

/* ---------- News ---------- */
.news-list { list-style: none; margin: 0; padding: 0; }
.news-item { display: grid; grid-template-columns: 110px 1fr; gap: 16px; padding: 16px 0; border-bottom: 1px solid var(--line); }
.news-item:last-child { border-bottom: 0; }
.news-date { color: var(--teal); font-weight: 700; font-size: .9rem; font-variant-numeric: tabular-nums; }
.news-cat {
  display: inline-block; font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .06em;
  color: var(--navy-2); background: var(--teal-light); padding: 2px 8px; border-radius: 6px; margin-right: 8px;
}
@media (max-width: 560px) { .news-item { grid-template-columns: 1fr; gap: 4px; } }

/* ---------- Publications ---------- */
.pub-toolbar { display: flex; gap: 12px; flex-wrap: wrap; align-items: center; margin-bottom: 24px; }
.tabs { display: flex; gap: 6px; flex-wrap: wrap; }
.tab {
  border: 1px solid var(--line); background: #fff; color: var(--ink); padding: 8px 14px; border-radius: 999px;
  font: inherit; font-size: .9rem; cursor: pointer;
}
.tab.active { background: var(--navy); color: #fff; border-color: var(--navy); }
.tab .count { opacity: .65; margin-left: 4px; }
.search {
  flex: 1; min-width: 200px; padding: 9px 14px; border: 1px solid var(--line); border-radius: 999px; font: inherit; font-size: .92rem;
}
.search:focus, .tab:focus-visible { outline: 2px solid var(--sky); outline-offset: 1px; }
.year-group h3 { font-size: 1.05rem; color: var(--teal); border-bottom: 2px solid var(--teal-light); padding-bottom: 6px; margin-top: 28px; }
.pub { display: grid; grid-template-columns: 44px 1fr; gap: 10px; padding: 12px 0; border-bottom: 1px dashed var(--line); }
.pub-num { color: var(--muted); font-size: .85rem; font-variant-numeric: tabular-nums; padding-top: 2px; }
.pub-title { font-weight: 600; color: var(--navy); }
.pub-authors { font-size: .93rem; color: var(--ink); }
.pub-authors b { color: var(--teal); }
.pub-venue { font-size: .9rem; color: var(--muted); font-style: italic; }
.pub-links { margin-top: 4px; display: flex; gap: 8px; flex-wrap: wrap; }
.pub-links a, .badge {
  font-size: .75rem; padding: 2px 9px; border-radius: 6px; border: 1px solid var(--line); color: var(--navy-2);
}
.badge.award { background: #fff6e0; border-color: #f2d48a; color: #7a5600; }
.empty { color: var(--muted); padding: 24px 0; }

/* ---------- People ---------- */
.pi { display: grid; grid-template-columns: 220px 1fr; gap: 36px; align-items: start; }
@media (max-width: 760px) { .pi { grid-template-columns: 1fr; } .pi > .avatar { max-width: 180px; } }
.avatar {
  width: 100%; aspect-ratio: 4 / 5; border-radius: var(--radius); object-fit: cover;
  background: linear-gradient(160deg, var(--navy-2), var(--teal)); color: #fff;
  display: grid; place-items: center; font-size: 3rem; font-weight: 700;
}
.avatar.sm { aspect-ratio: 1; font-size: 1.6rem; border-radius: 50%; width: 120px; margin-bottom: 12px; }
.pi-role { color: var(--teal); font-weight: 600; margin-bottom: .2em; }
.pi-meta { color: var(--muted); font-size: .95rem; }
.timeline { list-style: none; margin: 0; padding: 0; }
.timeline li { display: grid; grid-template-columns: 150px 1fr; gap: 12px; padding: 8px 0; border-bottom: 1px solid var(--line); font-size: .95rem; }
.timeline li span:first-child { color: var(--muted); font-variant-numeric: tabular-nums; }
@media (max-width: 560px) { .timeline li { grid-template-columns: 1fr; gap: 0; } }
.member-card { text-align: center; }
.member-card .avatar.sm { margin: 0 auto 12px; }
.member-card h4 { margin: 0; }
.member-card p { margin: 2px 0 0; font-size: .88rem; }

.callout {
  border-radius: var(--radius); padding: 32px; color: #fff;
  background: linear-gradient(135deg, var(--teal) 0%, var(--navy-2) 100%);
}
.callout h2, .callout h3 { color: #fff; }
.callout p { color: rgba(255, 255, 255, .88); }
.callout .btn-primary { background: #fff; }

/* ---------- Research ---------- */
.research-block { display: grid; grid-template-columns: 1fr 1.4fr; gap: 40px; padding: 40px 0; border-bottom: 1px solid var(--line); }
.research-block:last-child { border-bottom: 0; }
@media (max-width: 860px) { .research-block { grid-template-columns: 1fr; gap: 16px; } }
.research-block ul { margin: 0; padding-left: 1.2em; color: var(--ink); }
.research-block li { margin-bottom: .35em; }
.research-num { font-size: .85rem; font-weight: 700; color: var(--teal); letter-spacing: .1em; }
.project { padding: 16px 0; border-bottom: 1px solid var(--line); }
.project:last-child { border-bottom: 0; }
.project h4 { margin: 0 0 4px; font-size: 1rem; }
.project p { margin: 0; color: var(--muted); font-size: .9rem; }
.status { font-size: .72rem; font-weight: 700; padding: 2px 8px; border-radius: 6px; margin-left: 6px; vertical-align: middle; }
.status.on { background: #e3f6e9; color: #1d7a3c; }
.status.done { background: var(--bg-soft); color: var(--muted); }

/* ---------- Contact ---------- */
.contact-list { list-style: none; padding: 0; margin: 0; }
.contact-list li { display: grid; grid-template-columns: 90px 1fr; padding: 12px 0; border-bottom: 1px solid var(--line); }
.contact-list li span:first-child { color: var(--muted); font-size: .9rem; }
.map { width: 100%; height: 360px; border: 0; border-radius: var(--radius); }

/* ---------- Footer ---------- */
.site-footer { background: var(--navy); color: rgba(255, 255, 255, .72); padding: 40px 0; font-size: .9rem; }
.site-footer a { color: var(--sky); }
.footer-inner { display: flex; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
.footer-inner strong { color: #fff; }
/* Links page */
.link-jump { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 8px; }
.link-jump .tag { font-size: .9rem; padding: 6px 14px; }
.link-jump .tag:hover { border-color: var(--teal); color: var(--teal); text-decoration: none; }
.link-group { padding-top: 32px; scroll-margin-top: 80px; }
.link-group + .link-group { margin-top: 24px; border-top: 1px solid var(--line); }
.link-sub h3 { font-size: 1.05rem; color: var(--teal); border-bottom: 2px solid var(--teal-light); padding-bottom: 6px; margin: 24px 0 14px; }
.link-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 12px; }
.link-card { display: flex; flex-direction: column; gap: 4px; padding: 14px 16px; background: #fff; border: 1px solid var(--line);
  border-radius: 12px; transition: border-color .15s, box-shadow .15s, transform .15s; }
.link-card:hover { border-color: var(--teal); box-shadow: 0 6px 18px rgba(11, 37, 64, .08); transform: translateY(-2px); text-decoration: none; }
.link-card strong { display: flex; align-items: flex-start; gap: 10px; color: var(--navy); line-height: 1.35; }
.link-card strong .nm { flex: 1; min-width: 0; padding-top: 2px; }
.link-card strong svg { flex: none; margin-top: 5px; color: var(--muted); }
.link-ico { position: relative; flex: none; width: 28px; height: 28px; border-radius: 7px; background: var(--teal-light);
  display: grid; place-items: center; overflow: hidden; }
.link-ico b { color: var(--teal); font-size: .9rem; font-weight: 800; }
.link-ico img { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: contain; padding: 3px; background: #fff;
  border: 1px solid var(--line); border-radius: 7px; }
.link-card:hover strong svg { color: var(--teal); }
.link-card .desc { color: var(--muted); font-size: .88rem; line-height: 1.45; }
.link-card .host { color: var(--teal); font-size: .78rem; margin-top: auto; padding-top: 4px; }
@media (max-width: 620px) {
  .link-grid { gap: 8px; }
  .link-card { padding: 10px 14px; gap: 2px; }
  .link-card .desc { font-size: .84rem; }
  .link-card .host { display: none; }
}

.visits { display: inline-block; margin-top: 6px; font-size: .8rem; opacity: .7; font-variant-numeric: tabular-nums; }
.visits[hidden] { display: none; }