:root {
  --color-primary: #1a3c6e;
  --color-primary-dark: #102847;
  --color-accent: #3b82c4;
  --color-bg: #f7f8fa;
  --color-surface: #ffffff;
  --color-text: #1f2937;
  --color-text-muted: #5b6472;
  --color-border: #e2e5ea;
  --max-width: 1080px;
  --radius: 10px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: "Segoe UI", "Noto Sans KR", -apple-system, sans-serif;
  background: var(--color-bg);
  color: var(--color-text);
  line-height: 1.6;
}

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

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

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

/* Header / Nav */
header.site-header {
  background: var(--color-primary);
  color: #fff;
  position: sticky;
  top: 0;
  z-index: 10;
}

.nav-wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 20px;
  max-width: var(--max-width);
  margin: 0 auto;
  flex-wrap: wrap;
  gap: 10px;
}

.site-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: #fff;
}
.site-title:hover { text-decoration: none; opacity: 0.9; }

.site-title .sub {
  display: block;
  font-size: 0.75rem;
  font-weight: 400;
  color: #cdd9ea;
}

nav.main-nav ul {
  list-style: none;
  display: flex;
  gap: 4px;
  margin: 0;
  padding: 0;
  flex-wrap: wrap;
}

nav.main-nav a {
  color: #e8edf5;
  padding: 8px 14px;
  border-radius: 6px;
  font-weight: 500;
  font-size: 0.95rem;
}

nav.main-nav a:hover,
nav.main-nav a.active {
  background: rgba(255,255,255,0.15);
  text-decoration: none;
  color: #fff;
}

/* Hero */
.hero {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: #fff;
  padding: 56px 20px;
}
.hero .container { text-align: center; }
.hero h1 { font-size: 2.1rem; margin: 0 0 10px; }
.hero p { color: #d7e2f0; max-width: 640px; margin: 0 auto; font-size: 1.05rem; }

/* Page header (non-home) */
.page-header {
  padding: 40px 20px 20px;
}
.page-header h1 { margin: 0 0 6px; font-size: 1.8rem; }
.page-header p { color: var(--color-text-muted); margin: 0; }

/* Sections */
section { padding: 40px 0; }
section h2 {
  font-size: 1.4rem;
  margin: 0 0 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-border);
}

/* Cards */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 20px;
}

/* News list */
.news-list { list-style: none; margin: 0; padding: 0; }
.news-list li {
  display: flex;
  gap: 14px;
  padding: 12px 0;
  border-bottom: 1px solid var(--color-border);
}
.news-list li:last-child { border-bottom: none; }
.news-date {
  flex: 0 0 110px;
  color: var(--color-accent);
  font-weight: 600;
  font-size: 0.85rem;
  white-space: nowrap;
  text-align: center;
  padding: 0 16px;
}
.news-text { flex: 1; }

/* People grid */
.people-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 20px;
}
.person-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  padding: 18px;
  text-align: center;
}
.avatar {
  width: 128px;
  height: 128px;
  border-radius: 50%;
  margin: 0 auto 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: #fff;
  font-weight: 700;
  font-size: 1.4rem;
  background: var(--color-accent);
  overflow: hidden;
}

.avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}
.person-card h3 { margin: 0 0 2px; font-size: 1.05rem; }
.person-card .role { color: var(--color-text-muted); font-size: 0.85rem; margin: 0 0 8px; }
.person-card .meta { font-size: 0.82rem; color: var(--color-text-muted); }
.person-card .meta a { display: block; }

.group-title {
  margin: 36px 0 16px;
  font-size: 1.1rem;
  color: var(--color-primary);
}
.group-title:first-of-type { margin-top: 0; }

/* Publications */
.pub-group { margin-bottom: 36px; }
.pub-list { list-style: none; margin: 0; padding: 0; }
.pub-list li {
  padding: 14px 0;
  border-bottom: 1px solid var(--color-border);
}
.pub-list li:last-child { border-bottom: none; }
.pub-venue {
  display: inline-block;
  background: var(--color-accent);
  color: #fff;
  font-size: 0.75rem;
  font-weight: 700;
  padding: 2px 8px;
  border-radius: 4px;
  margin-right: 8px;
}
.pub-title { font-weight: 600; }
.pub-authors { color: var(--color-text-muted); font-size: 0.9rem; margin-top: 2px; }
.pub-links { margin-top: 6px; font-size: 0.85rem; }
.pub-links a { margin-right: 12px; }

/* Research */
.research-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 24px;
}
.research-card h3 { margin-top: 0; }
.research-card .venue { color: var(--color-accent); font-weight: 600; font-size: 0.85rem; }

/* Footer */
footer.site-footer {
  margin-top: 60px;
  padding: 30px 20px;
  background: var(--color-primary-dark);
  color: #cdd9ea;
  text-align: center;
  font-size: 0.85rem;
}
footer.site-footer a { color: #fff; }

@media (max-width: 640px) {
  .hero h1 { font-size: 1.5rem; }
  nav.main-nav ul { gap: 2px; }
  nav.main-nav a { padding: 6px 10px; font-size: 0.88rem; }
}