/* Base */
:root {
  --bg: #ffffff;
  --text: #333333;
  --muted: #666666;
  --primary: #001e3f;
  --primary-dark: #003d5b;
  --accent: #1a5c88;
  --border: #dcdcdc;
  --bg-light: #f5f7fa;
  --bg-section: #fafbfc;
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.6 system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
}
img { max-width: 100%; display: block; }
.container { max-width: 1080px; margin: 0 auto; padding: 0 16px; }
.section { padding: 32px 0; }
.section h2 { margin: 0 0 16px; font-size: 24px; }
.btn { display: inline-block; padding: 10px 20px; border: 1px solid var(--border); border-radius: 4px; color: var(--text); text-decoration: none; transition: all 0.3s ease; }
.btn:hover { background: var(--bg-light); }
.btn.primary { background: var(--primary); color: #fff; border-color: var(--primary); }
.btn.primary:hover { background: var(--primary-dark); }

/* Header */
.site-header { border-bottom: 1px solid var(--border); background: var(--primary); position: sticky; top: 0; z-index: 10; box-shadow: 0 2px 4px rgba(0,0,0,0.1); }
.header-inner { display: flex; align-items: center; gap: 16px; padding: 12px 0; }
.branding { display: flex; align-items: center; gap: 12px; }
.college-logo { height: 45px; width: 45px; display: block; }
.logo { text-decoration: none; color: #ffffff; font-weight: 700; font-size: 17px; }
.site-nav { display: flex; flex-wrap: wrap; gap: 8px; }
.site-nav a { padding: 8px 14px; border-radius: 4px; text-decoration: none; color: #ffffff; transition: all 0.3s ease; }
.site-nav a:hover { background: var(--primary-dark); }
.site-nav a.active { background: var(--accent); color: #ffffff; }
.hamburger { display: none; font-size: 20px; padding: 6px 8px; color: #ffffff; background: transparent; border: none; cursor: pointer; }

/* Footer */
.site-footer { border-top: 1px solid var(--border); background: #001e3f; margin-top: 40px; color: #ffffff; }
.footer-inner { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; padding: 24px 0; }
.footer-inner p { margin: 4px 0; color: #d0d0d0; }
.footer-inner a { color: #ffffff; text-decoration: none; }
.footer-inner a:hover { color: var(--accent); }

/* Hero */
.hero { border-bottom: 1px solid var(--border); background: linear-gradient(135deg, #e8f1f8, #ffffff); }
.hero-inner { display: grid; grid-template-columns: 1.2fr 1fr; gap: 24px; align-items: center; padding: 48px 0; }
.hero-text h1 { margin: 0 0 12px; font-size: 36px; color: var(--primary); }
.hero-text p { margin: 0 0 20px; color: var(--muted); font-size: 18px; }
.hero-cta { display: flex; gap: 12px; }

/* Cards & grids */
.card-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
.card { border: 1px solid var(--border); border-radius: 8px; padding: 20px; background: #fff; transition: all 0.3s ease; box-shadow: 0 1px 3px rgba(0,0,0,0.05); }
.card:hover { box-shadow: 0 4px 12px rgba(0,91,172,0.15); transform: translateY(-2px); }
.card h3 { margin: 0 0 10px; font-size: 18px; color: var(--primary); }
.card .muted { color: var(--muted); }

/* News list */
.news-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 8px; }
.news-list li { display: flex; justify-content: space-between; align-items: center; gap: 8px; border-bottom: 1px dashed var(--border); padding: 10px 0; }
.news-list a { text-decoration: none; color: var(--text); transition: color 0.3s ease; }
.news-list a:hover { color: var(--primary); }
.news-date { color: var(--muted); font-size: 14px; background: var(--bg-light); padding: 2px 8px; border-radius: 3px; }

/* Section pages */
.section-page { padding: 60px 0; scroll-margin-top: 60px; }
.section-page h2 { margin: 0 0 24px; font-size: 28px; color: var(--primary); border-left: 4px solid var(--accent); padding-left: 16px; }
.section-page:nth-child(even) { background: var(--bg-section); }
.section-page:first-child { padding-top: 0; }

/* Markdown */
.markdown { line-height: 1.75; }
.markdown h1, .markdown h2, .markdown h3 { margin-top: 1em; }
.markdown img { border-radius: 8px; }
.markdown ul { padding-left: 20px; }
.markdown li { margin: 4px 0; }

/* About section */
.about-intro { background: #fff; border: 1px solid var(--border); border-radius: 8px; padding: 32px; box-shadow: 0 2px 8px rgba(0,0,0,0.05); }
.about-intro h3 { color: var(--primary); font-size: 22px; margin: 0 0 16px; border-bottom: 2px solid var(--accent); padding-bottom: 12px; }
.about-intro h3:not(:first-child) { margin-top: 32px; }
.about-desc-cn, .about-desc-en { font-size: 16px; line-height: 1.8; color: var(--text); text-align: justify; margin: 0; }
.about-desc-en { color: var(--muted); font-style: italic; }

/* People */
.people-section { margin: 28px 0; }
.people-section h3 { 
  color: var(--primary); 
  font-size: 28px; 
  margin: 0 0 24px; 
  border-left: 4px solid var(--accent); 
  padding-left: 16px; 
}
.person-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
.person-card { border: 1px solid var(--border); border-radius: 8px; padding: 16px; background: #fff; transition: all 0.3s ease; }
.person-card:hover { box-shadow: 0 4px 12px rgba(0,91,172,0.15); transform: translateY(-2px); }
.person-card img { width: 100%; aspect-ratio: 1/1; object-fit: cover; border-radius: 6px; }
.person-grid .person-card img { width: 180px; height: 180px; margin: 0 auto; }
.person-card .name { font-weight: 600; margin: 12px 0 4px; color: var(--primary-dark); }
.person-name-link { text-decoration: none; color: inherit; display: inline-block; }
.person-name-link .name { color: var(--primary); cursor: pointer; transition: color 0.3s ease; }
.person-name-link:hover .name { color: var(--accent); }
.person-card .meta { color: var(--muted); font-size: 14px; }

/* Student Groups */
.student-groups-container {
  display: flex;
  flex-direction: column;
  gap: 24px;
  margin-top: 20px;
}
.student-group-card {
  border: 2px solid var(--border);
  border-radius: 12px;
  padding: 9px 20px;
  background: var(--bg-section);
  box-shadow: 0 2px 8px rgba(0,0,0,0.05);
  transition: all 0.3s ease;
}
.student-group-card:hover {
  box-shadow: 0 4px 16px rgba(0,91,172,0.1);
  border-color: var(--accent);
}
.student-group-card .person-grid {
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}
.student-group-card .person-card {
  width: 100%;
  padding: 4px 10px 6px;
  display: flex;
  flex-direction: column;
  align-items: center;
}
.student-group-card .person-card img {
  margin-bottom: 4px;
}
.student-group-card .person-card .name {
  margin: 0 0 2px;
}
.student-group-card .person-card .meta {
  margin-bottom: 0px;
}
.student-group-card .person-card .muted {
  margin-bottom: 0;
}

/* Publications */
.filters { display: flex; gap: 10px; align-items: center; margin-bottom: 16px; }
.filters select, .filters button { padding: 6px 12px; border: 1px solid var(--border); border-radius: 4px; background: #fff; color: var(--text); cursor: pointer; }
.filters button:hover { background: var(--primary); color: #fff; }
.pub-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 16px; }
.pub-item { border-bottom: 1px solid var(--border); padding-bottom: 16px; }
.pub-item .title { color: var(--primary-dark); font-weight: 500; }
.pub-links a { margin-right: 12px; color: var(--primary); text-decoration: none; transition: color 0.3s ease; }
.pub-links a:hover { color: var(--accent); }

/* Responsive */
@media (max-width: 960px) {
  .hero-inner { grid-template-columns: 1fr; }
  .card-grid { grid-template-columns: repeat(2, 1fr); }
  .person-grid { grid-template-columns: repeat(2, 1fr); }
  .student-group-card .person-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
  .site-nav { display: none; position: absolute; top: 58px; left: 0; right: 0; background: #fff; border-bottom: 1px solid var(--border); padding: 8px 16px; }
  .site-nav.open { display: grid; grid-template-columns: 1fr; gap: 4px; }
  .hamburger { display: inline-block; margin-left: auto; }
  .card-grid { grid-template-columns: 1fr; }
  .person-grid { grid-template-columns: 1fr; }
  .student-group-card .person-grid { grid-template-columns: 1fr; }
  .student-group-card { padding: 16px; }
}