/* =========================================================
   SLab — AI Medicine for Patient Safety Lab
   Color palette inspired by Seoul National University Hospital
   Typography: Pretendard
   ========================================================= */

:root {
  /* Brand — SNUH-inspired navy */
  --navy-900: #001E4C;
  --navy-800: #003876;   /* primary */
  --navy-700: #1B5BA8;
  --navy-100: #E8EFF8;
  --navy-50:  #F4F7FB;

  /* Accents */
  --teal:     #00A0B0;
  --gold:     #C8A24B;

  /* Neutrals */
  --ink-900:  #0F172A;
  --ink-700:  #1F2937;
  --ink-500:  #4B5563;
  --ink-400:  #6B7280;
  --ink-200:  #E5E7EB;
  --ink-100:  #F1F3F6;
  --bg:       #FFFFFF;
  --bg-soft:  #FAFBFD;

  /* Layout */
  --maxw: 1200px;
  --radius-sm: 6px;
  --radius:    10px;
  --radius-lg: 18px;
  --shadow-sm: 0 1px 2px rgba(15, 23, 42, .06);
  --shadow:    0 8px 24px rgba(15, 23, 42, .08);
  --shadow-lg: 0 20px 60px rgba(0, 30, 76, .12);

  /* Type */
  --font: 'Pretendard Variable', Pretendard, -apple-system, BlinkMacSystemFont,
          system-ui, Roboto, 'Helvetica Neue', 'Segoe UI', 'Apple SD Gothic Neo',
          'Noto Sans KR', sans-serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  font-family: var(--font);
  font-weight: 400;
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink-900);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; display: block; }
a   { color: var(--navy-800); text-decoration: none; transition: color .2s ease; }
a:hover { color: var(--navy-700); }

/* ========================== Header ========================== */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: rgba(255, 255, 255, .92);
  backdrop-filter: saturate(160%) blur(10px);
  -webkit-backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--ink-200);
}
.nav {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
  height: 72px;
  display: flex; align-items: center; justify-content: space-between;
}
.brand {
  display: flex; align-items: center; gap: 12px;
  font-weight: 800; color: var(--navy-900);
  letter-spacing: -0.01em;
}
.brand-mark {
  width: 38px; height: 38px; border-radius: 8px;
  background: linear-gradient(135deg, var(--navy-800) 0%, var(--navy-700) 100%);
  color: #fff; display: grid; place-items: center;
  font-weight: 800; font-size: 16px; letter-spacing: .02em;
  box-shadow: var(--shadow-sm);
}
.brand-name { font-size: 18px; }
.brand-sub  { font-size: 12px; color: var(--ink-400); font-weight: 500; letter-spacing: .02em; }

.nav-links {
  display: flex; gap: 4px; list-style: none; margin: 0; padding: 0;
}
.nav-links a {
  display: inline-block;
  padding: 10px 16px;
  font-weight: 600; font-size: 15px;
  color: var(--ink-700);
  border-radius: 8px;
  transition: background .2s ease, color .2s ease;
}
.nav-links a:hover { background: var(--navy-50); color: var(--navy-800); }
.nav-links a.active {
  color: var(--navy-800);
  background: var(--navy-100);
}

.menu-toggle {
  display: none; border: 1px solid var(--ink-200); background: #fff;
  width: 40px; height: 40px; border-radius: 8px;
  cursor: pointer;
}
.menu-toggle span, .menu-toggle::before, .menu-toggle::after {
  content: ""; display: block; height: 2px; background: var(--ink-900);
  width: 18px; margin: 4px auto;
}

@media (max-width: 860px) {
  .nav-links {
    position: absolute; top: 72px; left: 0; right: 0;
    flex-direction: column; gap: 0;
    background: #fff; border-bottom: 1px solid var(--ink-200);
    padding: 8px;
    transform-origin: top;
    transform: scaleY(0); transition: transform .2s ease;
  }
  .nav-links.open { transform: scaleY(1); }
  .nav-links a { padding: 14px 16px; border-radius: 0; }
  .menu-toggle { display: block; }
  .brand-sub { display: none; }
}

/* ========================== Hero ========================== */
.hero {
  position: relative;
  padding: 80px 24px 60px;
  background:
    radial-gradient(1200px 600px at 90% -10%, rgba(27,91,168,.10), transparent 60%),
    radial-gradient(900px 500px at -10% 0%, rgba(0,160,176,.08), transparent 60%),
    linear-gradient(180deg, #fff 0%, var(--bg-soft) 100%);
  border-bottom: 1px solid var(--ink-200);
  overflow: hidden;
}
.hero-inner {
  max-width: var(--maxw); margin: 0 auto;
  display: grid; grid-template-columns: 1.2fr 1fr; gap: 60px; align-items: center;
}
.eyebrow {
  display: inline-block;
  font-size: 13px; font-weight: 700;
  letter-spacing: .14em; text-transform: uppercase;
  color: var(--navy-800);
  padding: 6px 12px; border: 1px solid var(--navy-100);
  background: #fff; border-radius: 999px;
}
.hero h1 {
  font-size: clamp(34px, 5vw, 56px);
  line-height: 1.12; letter-spacing: -0.03em; font-weight: 800;
  color: var(--navy-900);
  margin: 18px 0 18px;
}
.hero h1 .accent { color: var(--navy-800); }
.hero p.lead {
  font-size: 18px; color: var(--ink-500);
  max-width: 580px;
}
.hero-meta {
  margin-top: 28px;
  display: flex; flex-wrap: wrap; gap: 10px;
}
.chip {
  font-size: 13px; font-weight: 600; color: var(--navy-800);
  padding: 8px 14px;
  background: #fff; border: 1px solid var(--navy-100); border-radius: 999px;
  box-shadow: var(--shadow-sm);
}
.hero-art {
  position: relative; aspect-ratio: 4/5; border-radius: var(--radius-lg);
  background: linear-gradient(160deg, var(--navy-800), var(--navy-700) 60%, var(--teal) 130%);
  overflow: hidden;
  box-shadow: var(--shadow-lg);
}
.hero-art::before {
  content: ""; position: absolute; inset: 0;
  background:
    radial-gradient(closest-side at 30% 20%, rgba(255,255,255,.18), transparent 60%),
    radial-gradient(closest-side at 80% 80%, rgba(0,160,176,.5), transparent 60%);
}
.hero-art .grid-lines {
  position: absolute; inset: 0;
  background:
    linear-gradient(to right, rgba(255,255,255,.08) 1px, transparent 1px) 0 0/40px 40px,
    linear-gradient(to bottom, rgba(255,255,255,.08) 1px, transparent 1px) 0 0/40px 40px;
  mask: linear-gradient(180deg, transparent, #000 25%, #000 75%, transparent);
}
.hero-art .label {
  position: absolute; left: 24px; bottom: 24px; right: 24px;
  color: #fff;
}
.hero-art .label small { opacity: .8; font-size: 12px; letter-spacing: .14em; text-transform: uppercase; }
.hero-art .label strong { display: block; font-size: 22px; font-weight: 700; margin-top: 6px; letter-spacing: -.01em; }

@media (max-width: 860px) {
  .hero { padding: 56px 20px 44px; }
  .hero-inner { grid-template-columns: 1fr; gap: 40px; }
  .hero-art { aspect-ratio: 16/10; }
}

/* ========================== Page header (shorter hero for sub-pages) ========================== */
.page-hero {
  background:
    radial-gradient(1000px 500px at 100% -10%, rgba(27,91,168,.08), transparent 60%),
    linear-gradient(180deg, #fff 0%, var(--bg-soft) 100%);
  padding: 64px 24px 36px;
  border-bottom: 1px solid var(--ink-200);
}
.page-hero-inner { max-width: var(--maxw); margin: 0 auto; }
.page-hero h1 {
  font-size: clamp(30px, 4vw, 44px);
  margin: 14px 0 8px;
  letter-spacing: -0.02em; line-height: 1.15; color: var(--navy-900);
  font-weight: 800;
}
.page-hero p { color: var(--ink-500); font-size: 17px; margin: 0; max-width: 720px; }

/* ========================== Sections ========================== */
section.section {
  padding: 80px 24px;
}
.section .container {
  max-width: var(--maxw); margin: 0 auto;
}
.section-title {
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 800; letter-spacing: -0.02em;
  color: var(--navy-900);
  margin: 0 0 10px;
}
.section-sub {
  color: var(--ink-500); margin: 0 0 36px; font-size: 16px;
}

/* Research cards on home */
.research-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}
.research-card {
  background: #fff; border: 1px solid var(--ink-200);
  border-radius: var(--radius); padding: 28px;
  transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
  position: relative; overflow: hidden;
}
.research-card::before {
  content: ""; position: absolute; left: 0; top: 0; bottom: 0; width: 4px;
  background: linear-gradient(180deg, var(--navy-800), var(--teal));
  opacity: .9;
}
.research-card:hover {
  transform: translateY(-3px);
  border-color: var(--navy-100);
  box-shadow: var(--shadow);
}
.research-card h3 {
  font-size: 18px; font-weight: 700; margin: 0 0 8px; color: var(--navy-900);
  letter-spacing: -0.01em;
}
.research-card p {
  color: var(--ink-500); margin: 0; font-size: 14.5px;
}
.research-card .num {
  font-size: 12px; color: var(--navy-800); font-weight: 700; letter-spacing: .12em;
}

/* Two-column collaboration block on home */
.split {
  display: grid; grid-template-columns: 1fr 1fr; gap: 56px; align-items: center;
}
.split h2 { margin-top: 0; }
.split .stat-row { display: flex; gap: 32px; margin-top: 24px; }
.stat { }
.stat .num { font-size: 32px; font-weight: 800; color: var(--navy-800); letter-spacing: -.02em; }
.stat .lbl { font-size: 13px; color: var(--ink-400); }
.split .visual {
  border-radius: var(--radius); border: 1px solid var(--ink-200);
  background: var(--bg-soft);
  aspect-ratio: 4/3;
  display: grid; place-items: center; color: var(--ink-400);
  background-image:
    radial-gradient(circle at 25% 30%, rgba(27,91,168,.10), transparent 40%),
    radial-gradient(circle at 75% 80%, rgba(0,160,176,.12), transparent 45%);
}
@media (max-width: 860px) {
  .split { grid-template-columns: 1fr; gap: 32px; }
  section.section { padding: 60px 20px; }
}

/* CTA banner */
.cta {
  background: linear-gradient(135deg, var(--navy-900), var(--navy-800));
  color: #fff; padding: 48px 32px; border-radius: var(--radius-lg);
  display: flex; align-items: center; justify-content: space-between; gap: 24px;
}
.cta h3 { margin: 0; font-size: 24px; font-weight: 700; letter-spacing: -0.01em; }
.cta p  { margin: 6px 0 0; opacity: .8; }
.btn {
  display: inline-block;
  background: #fff; color: var(--navy-800);
  padding: 12px 22px; border-radius: 999px; font-weight: 700; font-size: 15px;
  transition: transform .15s ease, box-shadow .2s ease;
  border: 1px solid transparent;
}
.btn:hover { transform: translateY(-1px); box-shadow: var(--shadow-sm); color: var(--navy-900); }
.btn.btn-outline {
  background: transparent; color: #fff; border-color: rgba(255,255,255,.5);
}
.btn.btn-outline:hover { background: rgba(255,255,255,.1); color: #fff; }

@media (max-width: 720px) {
  .cta { flex-direction: column; align-items: flex-start; }
}

/* ========================== Team ========================== */
.tabs {
  display: flex; flex-wrap: wrap; gap: 8px; margin: 0 0 40px;
  padding: 8px;
  background: var(--bg-soft); border: 1px solid var(--ink-200);
  border-radius: 14px;
  width: fit-content; max-width: 100%;
}
.tab {
  border: none; cursor: pointer; background: transparent;
  padding: 10px 18px; font: inherit; font-weight: 600; font-size: 14px;
  color: var(--ink-500); border-radius: 10px;
  transition: background .2s ease, color .2s ease;
}
.tab:hover { color: var(--navy-800); }
.tab.active {
  background: var(--navy-800); color: #fff;
  box-shadow: var(--shadow-sm);
}
.tab .count {
  display: inline-block; margin-left: 6px;
  font-size: 12px; padding: 2px 8px;
  background: rgba(255,255,255,.15); border-radius: 999px;
}
.tab:not(.active) .count {
  background: var(--ink-100); color: var(--ink-500);
}

.group {
  margin-bottom: 60px;
}
.group-title {
  display: flex; align-items: baseline; gap: 14px;
  font-size: 14px; font-weight: 700; letter-spacing: .14em;
  text-transform: uppercase; color: var(--navy-800);
  padding-bottom: 14px; margin-bottom: 28px;
  border-bottom: 1px solid var(--ink-200);
}
.group-title .num { color: var(--ink-400); font-weight: 600; letter-spacing: 0; }

.member-grid {
  display: grid; gap: 24px;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
}

.member {
  background: #fff; border: 1px solid var(--ink-200); border-radius: var(--radius);
  overflow: hidden; transition: transform .25s ease, box-shadow .25s ease, border-color .25s ease;
  display: grid; grid-template-rows: auto 1fr;
}
.member:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow);
  border-color: var(--navy-100);
}
.member .photo {
  width: 100%; aspect-ratio: 1/1;
  background: var(--bg-soft);
  background-size: cover; background-position: center 25%;
  position: relative;
}
.member .photo::after {
  content: ""; position: absolute; inset: auto 0 0 0; height: 30%;
  background: linear-gradient(180deg, transparent, rgba(0,30,76,.18));
  pointer-events: none;
}
.member .body { padding: 18px 20px 22px; }
.member .name {
  font-size: 17px; font-weight: 700; color: var(--navy-900);
  letter-spacing: -.01em; margin: 0;
}
.member .name .kr { color: var(--ink-500); font-weight: 500; margin-left: 6px; font-size: 14px; }
.member .role {
  font-size: 13px; color: var(--navy-800); font-weight: 600;
  letter-spacing: .04em; margin-top: 4px;
}
.member .meta {
  margin-top: 12px; padding-top: 12px;
  border-top: 1px dashed var(--ink-200);
  font-size: 13px; color: var(--ink-500); line-height: 1.55;
}
.member .meta strong { color: var(--ink-700); font-weight: 600; }
.member .interests {
  margin-top: 10px; display: flex; flex-wrap: wrap; gap: 6px;
}
.member .interests span {
  font-size: 11.5px; font-weight: 600;
  background: var(--navy-50); color: var(--navy-800);
  padding: 4px 10px; border-radius: 999px;
}

.empty-note {
  padding: 40px; text-align: center;
  background: var(--bg-soft); border: 1px dashed var(--ink-200);
  border-radius: var(--radius); color: var(--ink-400);
  font-size: 14px;
}

/* ========================== Publications ========================== */
.pub-toolbar {
  display: flex; flex-wrap: wrap; gap: 12px; align-items: center;
  margin-bottom: 32px;
}
.year-nav {
  display: flex; gap: 6px; flex-wrap: wrap;
  padding: 8px; background: var(--bg-soft); border: 1px solid var(--ink-200);
  border-radius: 12px;
}
.year-nav a {
  padding: 8px 14px; font-size: 13px; font-weight: 700;
  color: var(--ink-500); border-radius: 8px;
}
.year-nav a:hover { background: #fff; color: var(--navy-800); }
.year-nav a.active { background: var(--navy-800); color: #fff; }

.year-block {
  margin-bottom: 56px;
  scroll-margin-top: 100px;
}
.year-head {
  display: flex; align-items: baseline; gap: 16px; margin-bottom: 24px;
  padding-bottom: 14px; border-bottom: 2px solid var(--navy-800);
}
.year-head h2 {
  margin: 0; font-size: 32px; font-weight: 800; letter-spacing: -.02em;
  color: var(--navy-900);
}
.year-head .line { flex: 1; height: 1px; background: var(--ink-200); }

.sub-head {
  font-size: 12px; font-weight: 700; letter-spacing: .14em; text-transform: uppercase;
  color: var(--navy-800);
  background: var(--navy-50); display: inline-block;
  padding: 5px 12px; border-radius: 999px; margin: 12px 0 12px;
}

.pub-list { list-style: none; margin: 0; padding: 0; counter-reset: pub; }
.pub-list li {
  position: relative;
  padding: 16px 0 16px 56px;
  border-bottom: 1px solid var(--ink-100);
  font-size: 14.5px; color: var(--ink-700); line-height: 1.65;
}
.pub-list li:last-child { border-bottom: none; }
.pub-list li::before {
  counter-increment: pub;
  content: counter(pub, decimal-leading-zero);
  position: absolute; left: 0; top: 18px;
  font-size: 12px; font-weight: 700; color: var(--navy-800);
  letter-spacing: .04em;
  background: var(--navy-50);
  padding: 4px 10px; border-radius: 6px;
}
.pub-list li .authors { color: var(--ink-700); }
.pub-list li .title { color: var(--ink-900); font-weight: 600; }
.pub-list li .venue { color: var(--ink-500); font-style: italic; }
.pub-list li .if {
  display: inline-block; margin-left: 6px;
  font-size: 11px; padding: 2px 8px; border-radius: 999px;
  background: var(--navy-100); color: var(--navy-800); font-weight: 700; font-style: normal;
}

/* ========================== Gallery ========================== */
.gallery-grid {
  display: grid; gap: 16px;
  grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
}
.gal {
  border-radius: var(--radius); overflow: hidden; position: relative;
  background: var(--bg-soft);
  margin: 0; /* reset figure default margin */
  aspect-ratio: 4/3;
}
.gal img { width: 100%; height: 100%; object-fit: cover; display: block; transition: transform .4s ease; }
.gal:hover img { transform: scale(1.05); }
.gal .cap {
  position: absolute; left: 0; right: 0; bottom: 0; padding: 14px 16px;
  color: #fff; font-size: 13px; font-weight: 600;
  background: linear-gradient(180deg, transparent, rgba(0,30,76,.7));
}

@media (max-width: 540px) {
  .gallery-grid { grid-template-columns: repeat(2, 1fr); gap: 12px; }
}

/* placeholder visuals — applied when image fails to load (e.g. before sample photos are uploaded) */
.gal.placeholder {
  display: grid; place-items: center; color: var(--ink-400);
  background:
    repeating-linear-gradient(45deg, var(--bg-soft) 0 10px, #fff 10px 20px);
}
.gal.placeholder .cap {
  position: static; padding: 0;
  font-size: 13px; font-weight: 600; color: var(--navy-800);
  background: #fff; padding: 6px 12px; border-radius: 999px;
  border: 1px solid var(--ink-200);
}

/* ========================== Contact ========================== */
.contact-grid {
  display: grid; grid-template-columns: 1.2fr 1fr; gap: 48px;
}
.contact-card {
  background: #fff; border: 1px solid var(--ink-200); border-radius: var(--radius);
  padding: 28px;
}
.contact-card h3 {
  margin: 0 0 8px; font-size: 18px; color: var(--navy-900); letter-spacing: -.01em;
}
.contact-card p { margin: 0; color: var(--ink-500); }
.contact-list { list-style: none; padding: 0; margin: 0; display: grid; gap: 18px; }
.contact-list li { display: flex; gap: 16px; align-items: flex-start; }
.contact-list .ico {
  flex-shrink: 0; width: 42px; height: 42px; border-radius: 10px;
  background: var(--navy-50); color: var(--navy-800);
  display: grid; place-items: center; font-weight: 800;
}
.contact-list .label { font-size: 12px; color: var(--ink-400); font-weight: 700; letter-spacing: .12em; text-transform: uppercase; }
.contact-list .val { font-size: 15px; color: var(--ink-900); font-weight: 600; margin-top: 2px; }

.map {
  width: 100%; aspect-ratio: 4/3; border-radius: var(--radius);
  border: 1px solid var(--ink-200); background: var(--bg-soft);
  background-image:
    radial-gradient(circle at 30% 40%, rgba(27,91,168,.15), transparent 50%),
    radial-gradient(circle at 70% 70%, rgba(0,160,176,.10), transparent 50%);
  display: grid; place-items: center; color: var(--ink-400);
  font-weight: 600;
}

@media (max-width: 860px) {
  .contact-grid { grid-template-columns: 1fr; }
}

/* ========================== Footer ========================== */
.site-footer {
  margin-top: 80px; background: var(--navy-900); color: #fff;
}
.site-footer .inner {
  max-width: var(--maxw); margin: 0 auto;
  padding: 56px 24px 32px;
  display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 48px;
}
.site-footer h4 {
  font-size: 13px; font-weight: 700; letter-spacing: .14em; text-transform: uppercase;
  color: rgba(255,255,255,.55); margin: 0 0 14px;
}
.site-footer p, .site-footer a { color: rgba(255,255,255,.85); font-size: 14px; }
.site-footer a:hover { color: #fff; }
.site-footer ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 10px; }
.site-footer .brand-wrap { display: flex; align-items: center; gap: 14px; margin-bottom: 16px; }
.site-footer .brand-wrap .brand-mark {
  background: rgba(255,255,255,.12);
  color: #fff;
}
.site-footer .brand-name { color: #fff; font-size: 17px; font-weight: 800; }
.bottom-bar {
  border-top: 1px solid rgba(255,255,255,.1);
  padding: 18px 24px;
  text-align: center; color: rgba(255,255,255,.55); font-size: 12px;
}
@media (max-width: 860px) {
  .site-footer .inner { grid-template-columns: 1fr; gap: 32px; }
}

/* Stagger reveal */
@keyframes rise {
  from { opacity: 0; transform: translateY(10px); }
  to   { opacity: 1; transform: translateY(0); }
}
.reveal > * { animation: rise .5s ease forwards; opacity: 0; }
.reveal > *:nth-child(1) { animation-delay: .02s; }
.reveal > *:nth-child(2) { animation-delay: .08s; }
.reveal > *:nth-child(3) { animation-delay: .14s; }
.reveal > *:nth-child(4) { animation-delay: .20s; }
.reveal > *:nth-child(5) { animation-delay: .26s; }
.reveal > *:nth-child(6) { animation-delay: .32s; }
.reveal > *:nth-child(n+7) { animation-delay: .38s; }