/* ========================
   Base & Reset
======================== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --blue-dark: #0a3162;
  --blue-main: #1a5fa8;
  --blue-mid:  #2d7dd2;
  --blue-light: #ddeeff;
  --blue-pale:  #f0f6ff;
  --gold:       #c8960c;
  --gold-light: #fdf3d6;
  --text-dark:  #1a1a2e;
  --text-mid:   #3d4a5c;
  --text-muted: #6b7a8d;
  --border:     #d0d9e8;
  --white:      #ffffff;
  --bg-light:   #f4f7fc;
}

html { scroll-behavior: smooth; }
body { font-family: 'Segoe UI', 'PingFang TC', 'Microsoft JhengHei', sans-serif; color: var(--text-dark); background: var(--white); line-height: 1.7; }
a { text-decoration: none; color: inherit; }
img { max-width: 100%; }

/* ========================
   Header
======================== */
header {
  background: var(--blue-dark);
  position: sticky; top: 0; z-index: 100;
  box-shadow: 0 2px 12px rgba(0,0,0,0.25);
}
.header-inner {
  max-width: 1140px; margin: 0 auto;
  padding: 0 2rem;
  display: flex; align-items: center; gap: 2rem;
  height: 68px;
}
.logo-block { display: flex; align-items: center; gap: 14px; flex-shrink: 0; }
.logo-icon {
  width: 44px; height: 44px; border-radius: 6px;
  background: var(--gold); color: var(--blue-dark);
  font-weight: 700; font-size: 13px;
  display: flex; align-items: center; justify-content: center;
  letter-spacing: 0.5px;
}
.logo-title { color: #fff; font-size: 17px; font-weight: 600; line-height: 1.3; }
.logo-sub { color: rgba(255,255,255,0.62); font-size: 12px; }
nav { margin-left: auto; display: flex; gap: 0.25rem; }
nav a {
  color: rgba(255,255,255,0.8); font-size: 14px;
  padding: 6px 13px; border-radius: 4px;
  transition: background 0.18s, color 0.18s;
}
nav a:hover, nav a.active {
  background: rgba(255,255,255,0.12); color: #fff;
}
nav a.active { font-weight: 600; }
.menu-btn {
  display: none; background: none; border: none;
  color: #fff; font-size: 22px; cursor: pointer; padding: 6px;
}
.mobile-nav {
  display: none; flex-direction: column;
  background: var(--blue-dark); border-top: 1px solid rgba(255,255,255,0.1);
}
.mobile-nav.open { display: flex; }
.mobile-nav a {
  color: rgba(255,255,255,0.85); padding: 14px 2rem;
  border-bottom: 1px solid rgba(255,255,255,0.06); font-size: 15px;
}
.mobile-nav a:hover { background: rgba(255,255,255,0.07); }

/* ========================
   Hero
======================== */
.hero {
  background: linear-gradient(135deg, var(--blue-dark) 0%, #16407a 55%, #1a5fa8 100%);
  padding: 5rem 2rem 4rem;
}
.hero-inner {
  max-width: 1140px; margin: 0 auto;
  display: grid; grid-template-columns: 1fr 340px; gap: 4rem; align-items: center;
}
.hero-eyebrow { color: var(--gold); font-size: 13px; font-weight: 600; letter-spacing: 2px; text-transform: uppercase; margin-bottom: 1rem; }
.hero h1 { font-size: 3.2rem; font-weight: 700; color: #fff; line-height: 1.2; margin-bottom: 1.5rem; }
.hero-desc { color: rgba(255,255,255,0.78); font-size: 1.05rem; max-width: 480px; margin-bottom: 2rem; }
.hero-btns { display: flex; gap: 1rem; flex-wrap: wrap; }
.btn-primary {
  background: var(--gold); color: var(--blue-dark);
  padding: 12px 28px; border-radius: 6px; font-weight: 600; font-size: 15px;
  transition: opacity 0.18s;
}
.btn-primary:hover { opacity: 0.88; }
.btn-outline {
  border: 1.5px solid rgba(255,255,255,0.55); color: #fff;
  padding: 12px 28px; border-radius: 6px; font-weight: 500; font-size: 15px;
  transition: background 0.18s;
}
.btn-outline:hover { background: rgba(255,255,255,0.1); }

.hero-card {
  background: #fff; border-radius: 12px;
  padding: 2rem 1.75rem;
  box-shadow: 0 8px 40px rgba(0,0,0,0.28);
}
.prof-avatar {
  width: 72px; height: 72px; border-radius: 50%;
  background: var(--blue-main); color: #fff;
  font-size: 28px; font-weight: 700;
  display: flex; align-items: center; justify-content: center;
  margin: 0 auto 0.75rem;
}
.prof-name { text-align: center; font-size: 18px; font-weight: 700; color: var(--text-dark); }
.prof-title { text-align: center; font-size: 13px; color: var(--blue-main); margin-bottom: 1.25rem; font-weight: 500; }
.prof-divider { border-top: 1px solid var(--border); margin-bottom: 1.25rem; }
.prof-info-row { display: flex; justify-content: space-between; font-size: 13.5px; padding: 5px 0; color: var(--text-mid); gap: 8px; }
.prof-info-row .label { color: var(--text-muted); flex-shrink: 0; }

/* ========================
   Stats Bar
======================== */
.stats-bar { background: var(--blue-main); padding: 1.5rem 2rem; }
.stats-inner {
  max-width: 1140px; margin: 0 auto;
  display: flex; align-items: center; justify-content: center; gap: 0; flex-wrap: wrap;
}
.stat { text-align: center; padding: 0.5rem 3rem; }
.stat-num { display: block; font-size: 2rem; font-weight: 700; color: #fff; }
.stat-label { font-size: 13px; color: rgba(255,255,255,0.75); margin-top: 2px; }
.stat-div { width: 1px; height: 40px; background: rgba(255,255,255,0.25); }

/* ========================
   Sections
======================== */
.section { padding: 5rem 2rem; }
.section.bg-light { background: var(--bg-light); }
.container { max-width: 1140px; margin: 0 auto; }
.section-header { text-align: center; margin-bottom: 3rem; }
.eyebrow { font-size: 12px; font-weight: 600; letter-spacing: 2.5px; text-transform: uppercase; color: var(--blue-main); margin-bottom: 0.5rem; }
.section-header h2 { font-size: 2rem; font-weight: 700; color: var(--text-dark); }

/* Research Cards */
.cards-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1.5rem; }
.card {
  background: var(--white); border: 1px solid var(--border);
  border-radius: 10px; padding: 1.75rem;
  transition: box-shadow 0.2s, transform 0.2s;
}
.card:hover { box-shadow: 0 6px 24px rgba(10,49,98,0.12); transform: translateY(-3px); }
.card-icon {
  width: 48px; height: 48px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
  font-size: 22px; margin-bottom: 1rem;
}
.card-icon.blue { background: var(--blue-pale); }
.card-icon.teal { background: #e0f5f0; }
.card-icon.navy { background: #e8edf8; }
.card-icon.gold { background: var(--gold-light); }
.card-icon.red { background: #fde8e8; }
.card-icon.purple { background: #f0e8fd; }
.card h3 { font-size: 17px; font-weight: 600; color: var(--text-dark); margin-bottom: 0.6rem; }
.card p { font-size: 14px; color: var(--text-muted); line-height: 1.7; }

/* Publications */
.pub-list { display: flex; flex-direction: column; gap: 0; margin-bottom: 2rem; }
.pub-item {
  display: flex; align-items: flex-start; gap: 1.25rem;
  padding: 1.25rem 0; border-bottom: 1px solid var(--border);
}
.pub-year { font-size: 13px; font-weight: 600; color: var(--blue-main); min-width: 42px; padding-top: 3px; }
.pub-content { flex: 1; }
.pub-title { font-size: 15px; font-weight: 600; color: var(--text-dark); margin-bottom: 0.3rem; line-height: 1.5; }
.pub-meta { font-size: 13px; color: var(--text-muted); }
.pub-meta em { font-style: italic; color: var(--text-mid); }
.pub-badge { font-size: 11px; font-weight: 600; padding: 3px 10px; border-radius: 20px; flex-shrink: 0; margin-top: 3px; }
.pub-badge.journal { background: var(--blue-pale); color: var(--blue-main); }
.pub-badge.conf { background: #e8f8ef; color: #1a7a45; }
.center-btn { text-align: center; }
.center-btn .btn-outline { border-color: var(--blue-main); color: var(--blue-main); display: inline-block; }
.center-btn .btn-outline:hover { background: var(--blue-pale); }

/* News */
.news-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; }
.news-card {
  border: 1px solid var(--border); border-top: 3px solid var(--blue-main);
  border-radius: 8px; padding: 1.5rem;
  background: var(--white);
}
.news-date { font-size: 12px; color: var(--text-muted); letter-spacing: 1px; margin-bottom: 0.6rem; }
.news-title { font-size: 16px; font-weight: 600; color: var(--text-dark); margin-bottom: 0.6rem; }
.news-body { font-size: 14px; color: var(--text-muted); line-height: 1.65; }

/* Footer */
footer { background: var(--blue-dark); padding: 3rem 2rem 0; }
.footer-inner {
  max-width: 1140px; margin: 0 auto;
  display: flex; justify-content: space-between; align-items: flex-start;
  flex-wrap: wrap; gap: 2rem; padding-bottom: 2.5rem;
  border-bottom: 1px solid rgba(255,255,255,0.12);
}
.footer-name { color: #fff; font-size: 17px; font-weight: 600; margin-bottom: 0.4rem; }
.footer-sub { color: rgba(255,255,255,0.55); font-size: 13px; line-height: 1.8; }
.footer-links { display: flex; gap: 0.5rem; flex-wrap: wrap; }
.footer-links a {
  color: rgba(255,255,255,0.65); font-size: 13.5px;
  padding: 4px 10px; border-radius: 4px;
  transition: color 0.15s;
}
.footer-links a:hover { color: #fff; }
.footer-bottom {
  max-width: 1140px; margin: 0 auto;
  text-align: center; padding: 1.25rem 0;
  color: rgba(255,255,255,0.35); font-size: 12px;
}

/* ========================
   Page Hero (sub pages)
======================== */
.page-hero {
  background: var(--blue-dark);
  padding: 3.5rem 2rem;
  text-align: center;
}
.page-hero h1 { color: #fff; font-size: 2.2rem; font-weight: 700; }
.page-hero p { color: rgba(255,255,255,0.68); margin-top: 0.5rem; font-size: 15px; }
.breadcrumb { color: rgba(255,255,255,0.5); font-size: 13px; margin-bottom: 0.75rem; }
.breadcrumb a { color: var(--gold); }

/* ========================
   About Page
======================== */
.about-grid { display: grid; grid-template-columns: 280px 1fr; gap: 3rem; align-items: start; }
.about-sidebar .avatar-lg {
  width: 100%; aspect-ratio: 1;
  border-radius: 12px; background: var(--blue-light);
  display: flex; align-items: center; justify-content: center;
  font-size: 60px; font-weight: 700; color: var(--blue-main);
  margin-bottom: 1.5rem;
}
.sidebar-card {
  background: var(--bg-light); border-radius: 10px;
  padding: 1.25rem; border: 1px solid var(--border);
}
.sidebar-card h4 { font-size: 13px; font-weight: 700; text-transform: uppercase; letter-spacing: 1px; color: var(--text-muted); margin-bottom: 1rem; }
.sidebar-row { display: flex; gap: 0.75rem; padding: 6px 0; font-size: 14px; border-bottom: 1px solid var(--border); }
.sidebar-row:last-child { border-bottom: none; }
.sidebar-row .k { color: var(--text-muted); flex-shrink: 0; min-width: 70px; }
.sidebar-row .v { color: var(--text-dark); }
.about-content h2 { font-size: 1.5rem; font-weight: 700; color: var(--text-dark); margin-bottom: 1rem; }
.about-content p { font-size: 15px; color: var(--text-mid); line-height: 1.85; margin-bottom: 1.25rem; }
.edu-item { display: flex; gap: 1rem; padding: 1rem 0; border-bottom: 1px solid var(--border); }
.edu-item:last-child { border-bottom: none; }
.edu-dot { width: 10px; height: 10px; border-radius: 50%; background: var(--blue-main); margin-top: 7px; flex-shrink: 0; }
.edu-year { font-size: 12px; color: var(--blue-main); font-weight: 600; margin-bottom: 3px; }
.edu-degree { font-size: 15px; font-weight: 600; color: var(--text-dark); }
.edu-school { font-size: 13px; color: var(--text-muted); }

/* ========================
   Teaching Page
======================== */
.course-section { margin-bottom: 2.5rem; }
.course-section h3 { font-size: 18px; font-weight: 700; color: var(--blue-dark); border-left: 4px solid var(--blue-main); padding-left: 12px; margin-bottom: 1.25rem; }
.course-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.course-table th { background: var(--blue-dark); color: #fff; padding: 10px 14px; text-align: left; font-weight: 600; }
.course-table td { padding: 10px 14px; border-bottom: 1px solid var(--border); }
.course-table tr:hover td { background: var(--blue-pale); }
.tag { display: inline-block; font-size: 11px; padding: 2px 9px; border-radius: 20px; font-weight: 600; }
.tag.ug { background: #e8f8ef; color: #1a7a45; }
.tag.grad { background: var(--blue-pale); color: var(--blue-main); }
.tag.phd { background: var(--gold-light); color: #7a5c0c; }

/* ========================
   Contact Page
======================== */
.contact-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 3rem; }
.contact-info-block h3 { font-size: 18px; font-weight: 700; color: var(--text-dark); margin-bottom: 1.25rem; }
.contact-row { display: flex; gap: 1rem; padding: 0.85rem 0; border-bottom: 1px solid var(--border); font-size: 15px; }
.contact-row:last-child { border-bottom: none; }
.contact-row .ci { font-size: 20px; flex-shrink: 0; }
.contact-row .ck { color: var(--text-muted); font-size: 13px; }
.contact-row .cv { color: var(--text-dark); font-weight: 500; margin-top: 2px; }
.contact-form-wrap h3 { font-size: 18px; font-weight: 700; color: var(--text-dark); margin-bottom: 1.25rem; }
.form-group { margin-bottom: 1.2rem; }
.form-group label { display: block; font-size: 13px; font-weight: 600; color: var(--text-mid); margin-bottom: 5px; }
.form-group input, .form-group textarea, .form-group select {
  width: 100%; padding: 10px 14px; border: 1px solid var(--border);
  border-radius: 6px; font-size: 15px; font-family: inherit;
  color: var(--text-dark); background: var(--white);
  transition: border-color 0.18s;
}
.form-group input:focus, .form-group textarea:focus {
  outline: none; border-color: var(--blue-main);
  box-shadow: 0 0 0 3px rgba(26,95,168,0.12);
}
.form-group textarea { resize: vertical; min-height: 130px; }
.submit-btn {
  background: var(--blue-main); color: #fff;
  padding: 12px 32px; border: none; border-radius: 6px;
  font-size: 15px; font-weight: 600; cursor: pointer;
  transition: background 0.18s;
  font-family: inherit;
}
.submit-btn:hover { background: var(--blue-dark); }
.map-placeholder {
  background: var(--bg-light); border: 1px solid var(--border);
  border-radius: 10px; padding: 2.5rem; text-align: center;
  margin-top: 2.5rem;
}
.map-placeholder p { color: var(--text-muted); font-size: 14px; }

/* ========================
   Responsive
======================== */
@media (max-width: 900px) {
  .hero-inner { grid-template-columns: 1fr; gap: 2.5rem; }
  .hero h1 { font-size: 2.4rem; }
  .hero-card { max-width: 380px; }
  .about-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }
  .stat { padding: 0.5rem 1.5rem; }
  .stat-div { display: none; }
}
@media (max-width: 680px) {
  nav { display: none; }
  .menu-btn { display: block; }
  .header-inner { padding: 0 1.25rem; }
  .hero { padding: 3rem 1.25rem; }
  .hero h1 { font-size: 2rem; }
  .section { padding: 3.5rem 1.25rem; }
  .footer-inner { flex-direction: column; }
  .footer-links { flex-direction: column; gap: 0; }
}