/* ---------- Tokens ---------- */
:root {
  --bg: #ffffff;
  --surface: #f6f7f9;
  --text: #16181d;
  --muted: #5a6270;
  --line: #e4e7ec;
  --accent: #3451d1;
  --accent-ink: #2a41a8;
  --accent-soft: #eef1fd;
  --header-bg: rgba(255, 255, 255, 0.85);

  --wrap: 820px;
  --gutter: 1.25rem;
  --date-col: 10rem;
  --radius: 10px;

  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial,
    "Noto Sans KR", "Apple SD Gothic Neo", "Malgun Gothic", sans-serif;

  color-scheme: light dark;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1115;
    --surface: #171a21;
    --text: #e9ebef;
    --muted: #9aa3b2;
    --line: #262b35;
    --accent: #8ea2ff;
    --accent-ink: #b4c0ff;
    --accent-soft: #1c2340;
    --header-bg: rgba(15, 17, 21, 0.85);
  }
}

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

html {
  scroll-padding-top: 4.5rem;
  -webkit-text-size-adjust: 100%;
}

@media (prefers-reduced-motion: no-preference) {
  html { scroll-behavior: smooth; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 1.0625rem/1.65 var(--font);
  -webkit-font-smoothing: antialiased;
}

.wrap {
  max-width: var(--wrap);
  margin: 0 auto;
  padding: 0 var(--gutter);
}

a {
  color: var(--accent);
  text-decoration: none;
}
a:hover {
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
}
:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 3px;
}

[hidden] { display: none !important; }

h1, h2, h3 { line-height: 1.25; margin: 0; }
p { margin: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }

.skip-link {
  position: absolute;
  left: 1rem;
  top: -4rem;
  background: var(--accent);
  color: var(--bg);
  padding: 0.5rem 0.9rem;
  border-radius: var(--radius);
  z-index: 20;
}
.skip-link:focus { top: 0.75rem; text-decoration: none; }

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: var(--bg);
  border-bottom: 1px solid var(--line);
}
@supports (backdrop-filter: blur(8px)) {
  .site-header {
    background: var(--header-bg);
    -webkit-backdrop-filter: saturate(180%) blur(10px);
    backdrop-filter: saturate(180%) blur(10px);
  }
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  min-height: 3.5rem;
}

.brand {
  color: var(--text);
  font-weight: 700;
  letter-spacing: -0.01em;
  white-space: nowrap;
}
.brand:hover { text-decoration: none; }

.site-nav ul {
  display: flex;
  gap: 0.25rem;
  overflow-x: auto;
  scrollbar-width: none;
}
.site-nav ul::-webkit-scrollbar { display: none; }

.site-nav a {
  display: block;
  padding: 0.35rem 0.7rem;
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.925rem;
  font-weight: 500;
  white-space: nowrap;
}
.site-nav a:hover { color: var(--text); text-decoration: none; background: var(--surface); }
.site-nav a[aria-current="true"] { color: var(--accent-ink); background: var(--accent-soft); }

/* ---------- Hero ---------- */
.hero {
  display: grid;
  grid-template-columns: 176px 1fr;
  gap: 2.5rem;
  align-items: center;
  padding-top: 3.5rem;
  padding-bottom: 0.5rem;
}

.portrait {
  width: 176px;
  aspect-ratio: 1;
  border-radius: 50%;
  overflow: hidden;
  background: var(--surface);
  box-shadow: 0 0 0 1px var(--line), 0 8px 24px rgba(0, 0, 0, 0.08);
}
.portrait img {
  display: block;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: 50% 8%;
}

.hero h1 {
  font-size: clamp(2rem, 5.5vw, 2.75rem);
  letter-spacing: -0.025em;
}
.role {
  margin-top: 0.4rem;
  font-size: 1.2rem;
  font-weight: 600;
}
.team {
  color: var(--muted);
  font-size: 1rem;
}
.bio {
  margin-top: 1rem;
  max-width: 62ch;
}

.links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1.25rem;
}
.pill {
  display: inline-block;
  padding: 0.3rem 0.85rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text);
  font-size: 0.925rem;
  font-weight: 500;
  line-height: 1.5;
  background: var(--bg);
}
.pill:hover {
  text-decoration: none;
  border-color: var(--accent);
  color: var(--accent-ink);
  background: var(--accent-soft);
}
.pill.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--bg);
}
.pill.primary:hover { background: var(--accent-ink); border-color: var(--accent-ink); color: var(--bg); }

/* ---------- Sections ---------- */
main > section { padding-top: 3.5rem; }

main > section > .wrap > h2 {
  font-size: 1.4rem;
  letter-spacing: -0.015em;
  margin-bottom: 1.1rem;
}

.subhead {
  margin: 2rem 0 0.5rem;
  font-size: 0.8rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--muted);
}
.subhead:first-of-type { margin-top: 0; }

/* Timeline rows: date on the left, content on the right */
.timeline > li,
.year-group {
  display: grid;
  grid-template-columns: var(--date-col) 1fr;
  column-gap: 1.5rem;
  padding: 0.9rem 0;
  border-top: 1px solid var(--line);
}
.timeline > li:last-child,
.year-group:last-child { border-bottom: 1px solid var(--line); }

.timeline time,
.when,
.year-group > h3 {
  color: var(--muted);
  font-size: 0.925rem;
  font-weight: 500;
  font-variant-numeric: tabular-nums;
  padding-top: 0.1rem;
}

.timeline h3 { font-size: 1.05rem; font-weight: 600; }
.timeline h3 .org { font-weight: 400; color: var(--muted); }
.detail { margin-top: 0.15rem; color: var(--muted); font-size: 0.975rem; }
.detail .strong { color: var(--text); }

.news-item strong { font-weight: 600; }

/* "Earlier news" disclosure */
.earlier { margin-top: 0.75rem; }
.earlier summary {
  cursor: pointer;
  width: max-content;
  color: var(--accent);
  font-size: 0.95rem;
  font-weight: 500;
  list-style: none;
}
.earlier summary::-webkit-details-marker { display: none; }
.earlier summary::before { content: "＋ "; }
.earlier[open] summary::before { content: "－ "; }
.earlier[open] summary { margin-bottom: 0.5rem; }
.earlier .timeline > li:last-child { border-bottom: 0; }

/* ---------- Publications ---------- */
.section-note { color: var(--muted); font-size: 0.975rem; margin: -0.5rem 0 1.25rem; }

.pubs > li + li { margin-top: 1rem; }
.pub-title { font-weight: 600; line-height: 1.4; }
.pub-title a { color: var(--text); }
.pub-title a:hover { color: var(--accent); }
.pub-authors, .pub-venue { color: var(--muted); font-size: 0.95rem; line-height: 1.5; }
.pub-authors strong { color: var(--text); font-weight: 600; }
.pub-venue { margin-top: 0.1rem; }

.tag {
  display: inline-block;
  margin-left: 0.35rem;
  padding: 0 0.55rem;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent-ink);
  font-size: 0.72rem;
  font-weight: 600;
  line-height: 1.6;
  vertical-align: 0.05em;
  white-space: nowrap;
}
.res {
  display: inline-block;
  margin-left: 0.35rem;
  padding: 0 0.55rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--muted);
  font-size: 0.72rem;
  font-weight: 600;
  line-height: 1.55;
  vertical-align: 0.05em;
  white-space: nowrap;
}
.res:hover { text-decoration: none; color: var(--accent-ink); border-color: var(--accent); }

/* ---------- Simple lists (awards, service, beyond work) ---------- */
.plain-list > li {
  position: relative;
  padding: 0.25rem 0 0.25rem 1.1rem;
}
.plain-list > li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.95em;
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent);
  opacity: 0.6;
}
.plain-list .yr { color: var(--muted); font-variant-numeric: tabular-nums; margin-right: 0.35rem; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 1rem;
}
.card {
  padding: 1.1rem 1.2rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--surface);
}
.card h3 { font-size: 1rem; margin-bottom: 0.35rem; }
.card p { color: var(--muted); font-size: 0.95rem; line-height: 1.55; }

/* ---------- Footer ---------- */
.site-footer {
  margin-top: 4rem;
  padding: 1.5rem 0 3rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.875rem;
}
.site-footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 0.5rem; }

/* ---------- Small screens ---------- */
@media (max-width: 640px) {
  body { font-size: 1rem; }

  .brand { display: none; }
  .site-nav { width: 100%; }

  .hero {
    grid-template-columns: 1fr;
    gap: 1.5rem;
    padding-top: 2.25rem;
    align-items: start;
  }
  .portrait { width: 128px; }

  main > section { padding-top: 2.75rem; }

  .timeline > li,
  .year-group { grid-template-columns: 1fr; row-gap: 0.15rem; }
}

/* ---------- Print ---------- */
@media print {
  .site-header, .skip-link, .earlier summary { display: none; }
  .earlier > * { display: block; }
  body { font-size: 10.5pt; }
  a { color: inherit; }
}