/* =========================================================
   D³ Lab — Data · Dynamics · Discovery
   Minimal white theme with one accent color.
   ========================================================= */

:root {
  --bg: #ffffff;
  --bg-soft: #f6f7f9;
  --fg: #111418;
  --muted: #5b6270;
  --line: #e6e8ec;
  --accent: #3b3fb6;
  --accent-soft: #eef0ff;
  --chart-2: #b7bccb;
  --chart-3: #d9dce5;

  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;

  --max: 1080px;
  --radius: 10px;
}

/* 다크: 시스템 설정을 따르되(:not light), 버튼으로 고른 테마(data-theme)가 우선 */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e1014;
    --bg-soft: #15181e;
    --fg: #e8eaef;
    --muted: #9aa1ad;
    --line: #23262d;
    --accent: #8b8ff0;
    --accent-soft: #1b1d33;
    --chart-2: #444a58;
    --chart-3: #2c3039;
  }
}
:root[data-theme="dark"] {
  --bg: #0e1014;
  --bg-soft: #15181e;
  --fg: #e8eaef;
  --muted: #9aa1ad;
  --line: #23262d;
  --accent: #8b8ff0;
  --accent-soft: #1b1d33;
  --chart-2: #444a58;
  --chart-3: #2c3039;
}


* { box-sizing: border-box; }

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

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; text-underline-offset: 3px; }

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

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

.muted { color: var(--muted); }

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

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--line);
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  font-weight: 700;
  font-size: 1.15rem;
  color: var(--fg);
  letter-spacing: -0.01em;
}
.logo:hover { text-decoration: none; }
.logo sup { color: var(--accent); font-size: 0.65em; }

.header-actions { display: flex; align-items: center; gap: 8px; }
.nav { display: flex; gap: 4px; }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--bg);
  color: var(--muted);
  cursor: pointer;
}
.theme-toggle:hover { color: var(--fg); border-color: var(--muted); }

.nav a {
  color: var(--muted);
  font-size: 0.92rem;
  padding: 6px 10px;
  border-radius: 6px;
}
.nav a:hover { color: var(--fg); background: var(--bg-soft); text-decoration: none; }
.nav a.active { color: var(--fg); font-weight: 600; }

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--line);
  border-radius: 6px;
  color: var(--fg);
  font: inherit;
  font-size: 0.9rem;
  padding: 4px 10px;
  cursor: pointer;
}

@media (max-width: 820px) {
  .nav-toggle { display: block; }
  .nav {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--bg);
    border-bottom: 1px solid var(--line);
    padding: 8px 16px 16px;
  }
  .nav.open { display: flex; }
}

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

.hero {
  position: relative;
  padding: 96px 0 72px;
  overflow: hidden;
  border-bottom: 1px solid var(--line);
}

.hero canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
}

.hero .container { position: relative; }
@media (max-width: 1023px) { .hero { padding-bottom: 150px; } }

.eyebrow {
  font-family: var(--font-sans);
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--muted);
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin: 0 0 16px;
}

.hero h1 {
  font-size: clamp(2.2rem, 6vw, 4rem);
  line-height: 1.08;
  letter-spacing: -0.03em;
  margin: 0 0 20px;
  font-weight: 700;
}
.hero h1 sup { color: var(--accent); font-size: 0.55em; vertical-align: 0.75em; margin-left: 0.02em; }
.hero .dot { color: var(--accent); }

.tagline {
  font-size: clamp(1.15rem, 2.4vw, 1.5rem);
  font-weight: 500;
  letter-spacing: -0.01em;
  margin: -6px 0 18px;
}

.hero .lead {
  font-size: clamp(1.05rem, 2vw, 1.25rem);
  color: var(--muted);
  margin: 0 0 32px;
}

.btn-row { display: flex; gap: 12px; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 10px 18px;
  border-radius: 8px;
  font-weight: 600;
  font-size: 0.95rem;
  border: 1px solid var(--line);
  color: var(--fg);
  background: var(--bg);
}
.btn:hover { text-decoration: none; border-color: var(--fg); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }

/* ---------- Page header (sub pages) ---------- */

.page-head {
  padding: 64px 0 32px;
  border-bottom: 1px solid var(--line);
}
.page-head h1 {
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  letter-spacing: -0.02em;
  margin: 0 0 8px;
}
.page-head p { color: var(--muted); margin: 0; }

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

section.block { padding: 64px 0; }
section.block + section.block { border-top: 1px solid var(--line); }

.section-title {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 28px;
}
.section-title h2 {
  font-size: 1.5rem;
  letter-spacing: -0.015em;
  margin: 0;
}
.section-title a { font-size: 0.9rem; }

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

.timeline { list-style: none; margin: 0; padding: 0; }

.timeline li {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 20px;
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}
.timeline li:last-child { border-bottom: none; }

.timeline time {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--muted);
  padding-top: 2px;
}

@media (max-width: 560px) {
  .timeline li { grid-template-columns: 1fr; gap: 2px; }
}

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

.pub-controls {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
  margin-bottom: 32px;
}

.chip {
  font: inherit;
  font-size: 0.85rem;
  padding: 6px 12px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--bg);
  color: var(--muted);
  cursor: pointer;
}
.chip.active { background: var(--fg); border-color: var(--fg); color: var(--bg); }

.search {
  font: inherit;
  font-size: 0.9rem;
  padding: 7px 12px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: var(--bg);
  color: var(--fg);
  min-width: 220px;
  flex: 1;
  max-width: 320px;
}

.pub-year {
  font-family: var(--font-mono);
  font-size: 0.95rem;
  color: var(--muted);
  margin: 36px 0 8px;
}

.pub-list { list-style: none; margin: 0; padding: 0; }

.pub {
  padding: 14px 0;
  border-bottom: 1px solid var(--line);
}
.pub-title { font-weight: 600; }
.pub-authors { color: var(--muted); font-size: 0.93rem; }
.pub-authors strong { color: var(--fg); font-weight: 600; }
.pub-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
  margin-top: 4px;
  font-size: 0.88rem;
}
.venue {
  font-family: var(--font-mono);
  font-size: 0.78rem;
  background: var(--accent-soft);
  color: var(--accent);
  padding: 2px 8px;
  border-radius: 4px;
}

.award {
  font-size: 0.78rem;
  font-weight: 600;
  color: #9a6700;
  background: #fff6db;
  padding: 2px 8px;
  border-radius: 4px;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .award { color: #f0c457; background: #2d2610; }
}
:root[data-theme="dark"] .award { color: #f0c457; background: #2d2610; }

/* 기업 협업 표시: 제목 끝, 강조색 테두리 (학회 태그는 배경이 채워진 모양이라 구분됨) */
.partner {
  display: inline-block;
  margin-left: 8px;
  vertical-align: 1px;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--accent);
  border: 1px solid var(--accent);
  padding: 0 7px;
  border-radius: 4px;
}

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

.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 28px;
}

.person { text-align: left; }

.avatar {
  width: 100%;
  aspect-ratio: 1 / 1;
  border-radius: var(--radius);
  background: var(--bg-soft);
  border: 1px solid var(--line);
  object-fit: cover;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2rem;
  font-weight: 600;
  color: var(--muted);
  margin-bottom: 12px;
}
.person h3 { font-size: 1.02rem; margin: 0; }
.person .role { color: var(--accent); font-size: 0.85rem; font-family: var(--font-mono); }
.person p { color: var(--muted); font-size: 0.9rem; margin: 6px 0 0; }

.pi-card {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 28px;
  align-items: center;
}
.pi-card .avatar { margin: 0; }
.pi-card h3 { font-size: 1.4rem; margin: 0 0 2px; }
.pi-card p { color: var(--fg); font-size: 0.95rem; margin: 12px 0 0; }
.pi-highlights { margin: 14px 0 0; padding-left: 18px; font-size: 0.92rem; color: var(--muted); }
.pi-card .pi-links { font-size: 0.92rem; }
.pi-card .avatar { aspect-ratio: 4 / 5; }
@media (max-width: 640px) { .pi-card { grid-template-columns: 1fr; } .pi-card .avatar { max-width: 160px; } }

.group-title {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  margin: 48px 0 20px;
}

.alumni-list { list-style: none; padding: 0; margin: 0; }
.alumni-list li { padding: 8px 0; border-bottom: 1px solid var(--line); }

/* ---------- Misc ---------- */

.callout {
  border: 1px solid var(--line);
  background: var(--bg-soft);
  border-radius: var(--radius);
  padding: 32px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 24px;
  flex-wrap: wrap;
}
.callout h3 { margin: 0 0 4px; font-size: 1.25rem; }
.callout p { margin: 0; color: var(--muted); }

.prose h2 { font-size: 1.35rem; margin: 40px 0 12px; letter-spacing: -0.01em; }
.prose h2:first-child { margin-top: 0; }
.prose ul { padding-left: 20px; }

.info-grid {
  display: grid;
  grid-template-columns: 160px 1fr;
  gap: 12px 24px;
}
.info-grid dt { color: var(--muted); font-family: var(--font-mono); font-size: 0.88rem; padding-top: 2px; }
.info-grid dd { margin: 0; }
@media (max-width: 560px) { .info-grid { grid-template-columns: 1fr; gap: 2px; } .info-grid dd { margin-bottom: 12px; } }

.course { padding: 18px 0; border-bottom: 1px solid var(--line); }
.course h3 { margin: 0; font-size: 1.05rem; }
.course .term { font-family: var(--font-mono); font-size: 0.85rem; color: var(--muted); }

.empty { color: var(--muted); font-style: italic; }

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

.site-footer {
  border-top: 1px solid var(--line);
  padding: 40px 0;
  margin-top: 40px;
  color: var(--muted);
  font-size: 0.88rem;
}
.site-footer .container {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  flex-wrap: wrap;
}
.site-footer strong { color: var(--fg); }
.footer-contact { text-align: right; line-height: 1.7; }
.site-footer .footer-copy { margin-top: 20px; font-size: 0.8rem; }
@media (max-width: 640px) { .footer-contact { text-align: left; } }


/* ---------- Hiring (홈, What we do 위) ---------- */
section.block.hiring-block { padding-bottom: 0; }
section.block.hiring-block + section.block { border-top: none; }
.hiring-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--bg-soft);
  padding: 28px 32px;
}
.hiring-head h2 { font-size: 1.35rem; margin: 0 0 4px; letter-spacing: -0.015em; }
.hiring-head p { margin: 0; color: var(--muted); }
.positions { list-style: none; margin: 18px 0; padding: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.positions li {
  font-size: 0.9rem;
  font-weight: 500;
  padding: 5px 12px;
  border-radius: 999px;
  background: var(--bg);
  border: 1px solid var(--line);
}
.hiring-apply { margin: 0; font-size: 0.93rem; color: var(--muted); }
.hiring-apply a { font-weight: 500; }
@media (max-width: 560px) { .hiring-card { padding: 22px 20px; } }

/* ---------- Research: 연구 방향 ---------- */
.direction .num { font-family: var(--font-mono); font-size: 0.85rem; color: var(--accent); }
.direction h2 { font-size: 1.5rem; letter-spacing: -0.015em; margin: 6px 0 14px; }
.direction-topics { margin: 0 0 8px; padding-left: 20px; color: var(--fg); }
.direction-topics li { margin: 4px 0; }
.direction-topics strong { font-weight: 600; }
.direction .group-title { margin-top: 32px; margin-bottom: 4px; }
.direction-note { margin: 0; }
.prose h3 { font-size: 1.05rem; margin: 24px 0 6px; }

.prose .positions { padding-left: 0; margin-top: 0; }

/* ---------- Home: 연구 방향 (한 줄씩) ---------- */
.directions { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line); }
.directions li {
  display: grid;
  grid-template-columns: 40px 290px 1fr;
  gap: 8px 24px;
  align-items: baseline;
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}
.directions .num { font-family: var(--font-mono); font-size: 0.85rem; color: var(--accent); }
.directions h3 { margin: 0; font-size: 1.1rem; }
.directions p { margin: 0; color: var(--muted); }
@media (max-width: 720px) {
  .directions li { grid-template-columns: 36px 1fr; }
  .directions p { grid-column: 2; }
}

/* 버튼 줄은 애니메이션과 같은 높이 */
@media (min-width: 1024px) { .hero .btn-row { margin-top: 44px; } }

/* ---------- Research: 방향별 애니메이션 ---------- */
.direction-body {
  display: grid;
  grid-template-columns: 1fr 380px;
  gap: 24px 48px;
  align-items: center;
}
.direction-anim { display: block; width: 100%; height: 190px; }
@media (max-width: 860px) {
  .direction-body { grid-template-columns: 1fr; }
  .direction-anim { max-width: 440px; }
}

/* 내용이 짧은 페이지에서도 푸터가 화면 아래에 오도록 */
main { flex: 1 0 auto; }