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

:root {
  --primary: #2c3e50;
  --accent: #3498db;
  --accent-dark: #2980b9;
  --text: #333;
  --text-light: #666;
  --bg: #ffffff;
  --bg-light: #f8f9fa;
  --border: #e0e0e0;
  --sidebar-width: 280px;
  --nav-height: 56px;
}

html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--text); background: var(--bg); line-height: 1.7; font-size: 15px;
}

a { color: var(--accent); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--accent-dark); text-decoration: underline; }
img { max-width: 100%; height: auto; }

/* ===== TOP NAVIGATION ===== */
.top-nav {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--nav-height); background: var(--primary);
  display: flex; align-items: center; justify-content: center;
  z-index: 1000; box-shadow: 0 2px 8px rgba(0,0,0,0.15);
}
.nav-inner {
  display: flex; align-items: center; justify-content: space-between;
  width: 100%; max-width: 1100px; padding: 0 24px;
}
.nav-brand { font-size: 18px; font-weight: 700; color: #fff; letter-spacing: 0.02em; }
.nav-brand:hover { color: #fff; text-decoration: none; }
.nav-links { display: flex; gap: 4px; list-style: none; }
.nav-links a {
  color: rgba(255,255,255,0.85); padding: 8px 14px; border-radius: 6px;
  font-size: 14px; font-weight: 500; transition: all 0.2s;
}
.nav-links a:hover, .nav-links a.active {
  color: #fff; background: rgba(255,255,255,0.15); text-decoration: none;
}
.hamburger {
  display: none; flex-direction: column; gap: 5px; cursor: pointer;
  padding: 8px; background: none; border: none;
}
.hamburger span { display: block; width: 22px; height: 2px; background: #fff; border-radius: 2px; }

/* ===== LAYOUT ===== */
.page-wrapper {
  margin-top: var(--nav-height); display: flex;
  max-width: 1100px; margin-left: auto; margin-right: auto;
  min-height: calc(100vh - var(--nav-height));
}

/* ===== SIDEBAR ===== */
.sidebar {
  width: var(--sidebar-width); padding: 40px 24px;
  position: sticky; top: var(--nav-height);
  height: fit-content; max-height: calc(100vh - var(--nav-height));
  overflow-y: auto; flex-shrink: 0;
}
.profile-card { text-align: center; }
.profile-photo {
  width: 180px; height: 180px; border-radius: 50%; object-fit: cover;
  border: 4px solid var(--border); margin-bottom: 16px; transition: transform 0.3s;
}
.profile-photo:hover { transform: scale(1.03); }
.profile-name { font-size: 20px; font-weight: 700; color: var(--primary); margin-bottom: 4px; }
.profile-title { font-size: 13px; color: var(--text-light); margin-bottom: 2px; }
.profile-affiliation { font-size: 13px; color: var(--text-light); margin-bottom: 16px; }
.profile-links { display: flex; justify-content: center; gap: 12px; margin-bottom: 16px; }
.profile-links a {
  display: flex; align-items: center; justify-content: center;
  width: 36px; height: 36px; border-radius: 50%;
  background: var(--bg-light); color: var(--text-light); transition: all 0.2s;
}
.profile-links a:hover { background: var(--accent); color: #fff; text-decoration: none; }
.profile-links svg { width: 18px; height: 18px; }
.btn-cv {
  display: inline-block; padding: 8px 20px; background: var(--accent);
  color: #fff; border-radius: 6px; font-size: 13px; font-weight: 600;
  transition: background 0.2s; margin-bottom: 10px;
}
.btn-cv:hover { background: var(--accent-dark); color: #fff; text-decoration: none; }
.btn-email {
  display: inline-block; padding: 8px 20px; border: 1.5px solid var(--accent);
  color: var(--accent); border-radius: 6px; font-size: 13px; font-weight: 600; transition: all 0.2s;
}
.btn-email:hover { background: var(--accent); color: #fff; text-decoration: none; }

/* ===== MAIN CONTENT ===== */
.main-content {
  flex: 1; min-width: 0; padding: 40px 40px 60px 40px;
  border-left: 1px solid var(--border);
}
.page-title {
  font-size: 28px; font-weight: 700; color: var(--primary);
  margin-bottom: 8px; padding-bottom: 12px;
  border-bottom: 3px solid var(--accent); display: inline-block;
}
.section { margin-bottom: 36px; }
.section h2 {
  font-size: 20px; font-weight: 700; color: var(--primary);
  margin-bottom: 16px; padding-bottom: 6px; border-bottom: 2px solid var(--bg-light);
}
.section h3 { font-size: 16px; font-weight: 600; color: var(--primary); margin-bottom: 10px; margin-top: 20px; }
.section p { margin-bottom: 12px; }

/* ===== VIEW TOGGLE ===== */
.view-toggle {
  position: relative;
  display: inline-flex;
  background: var(--bg-light);
  border: 1px solid var(--border);
  border-radius: 50px;
  padding: 3px;
  margin-bottom: 28px;
  margin-top: 4px;
}
.view-toggle .slider {
  position: absolute;
  top: 3px;
  left: 3px;
  height: calc(100% - 6px);
  width: calc(50% - 3px);
  background: var(--primary);
  border-radius: 50px;
  transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
  box-shadow: 0 2px 10px rgba(44, 62, 80, 0.25);
  z-index: 0;
}
.view-toggle.topic .slider {
  transform: translateX(100%);
}
.toggle-btn {
  position: relative;
  z-index: 1;
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 9px 28px;
  border: none;
  border-radius: 50px;
  background: transparent;
  color: var(--text-light);
  font-family: inherit;
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: color 0.3s;
  white-space: nowrap;
  user-select: none;
}
.toggle-btn:hover {
  color: var(--text);
}
.toggle-btn.active {
  color: #fff;
}
.toggle-btn.active svg {
  stroke: #fff;
}
.toggle-btn svg {
  flex-shrink: 0;
  transition: stroke 0.3s;
}

/* ===== PUBLICATION STATUS LABELS ===== */
.pub-status {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  color: #e67e22;
  background: #fef5e7;
  padding: 1px 8px;
  border-radius: 4px;
  margin-left: 4px;
}
.pub-status-prep {
  display: inline-block;
  font-size: 12px;
  font-weight: 600;
  color: var(--text-light);
  background: var(--bg-light);
  padding: 1px 8px;
  border-radius: 4px;
  margin-left: 4px;
}

/* ===== PUBLICATIONS ===== */
.pub-list { list-style: none; }
.pub-item { padding: 14px 0; border-bottom: 1px solid var(--bg-light); line-height: 1.6; }
.pub-item:last-child { border-bottom: none; }
.pub-item .pub-authors strong { color: var(--accent-dark); }
.pub-item .pub-journal { font-style: italic; color: var(--text-light); }
.pub-item .pub-links { margin-top: 4px; }
.pub-item .pub-links a {
  display: inline-block; font-size: 12px; padding: 2px 10px;
  border: 1px solid var(--accent); border-radius: 4px;
  margin-right: 6px; margin-top: 4px; transition: all 0.2s;
}
.pub-item .pub-links a:hover { background: var(--accent); color: #fff; text-decoration: none; }

/* ===== RESEARCH CARDS ===== */
.research-areas { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; }
.research-card {
  background: var(--bg-light); border-radius: 10px; padding: 24px 20px;
  text-align: center; border: 1px solid var(--border); transition: transform 0.2s, box-shadow 0.2s;
}
.research-card:hover { transform: translateY(-3px); box-shadow: 0 4px 16px rgba(0,0,0,0.08); }
.research-card .icon { font-size: 32px; margin-bottom: 10px; }
.research-card h3 { font-size: 15px; font-weight: 600; color: var(--primary); margin: 0; }
.research-card p { font-size: 13px; color: var(--text-light); margin-top: 6px; }

/* ===== TEACHING ===== */
.teaching-group { margin-bottom: 28px; }
.course-list { list-style: none; }
.course-item {
  padding: 10px 0; border-bottom: 1px solid var(--bg-light);
  display: flex; flex-wrap: wrap; align-items: baseline; gap: 8px;
}
.course-item .course-name { font-weight: 600; color: var(--primary); }
.course-item .course-meta { font-size: 13px; color: var(--text-light); }
.course-item .course-eval { font-size: 12px; color: var(--accent-dark); margin-left: 4px; }
.course-materials { margin-top: 6px; width: 100%; }
.course-materials a {
  display: inline-block; font-size: 12px; padding: 2px 10px;
  border: 1px solid var(--accent); border-radius: 4px;
  margin-right: 6px; margin-top: 4px; transition: all 0.2s;
}
.course-materials a:hover { background: var(--accent); color: #fff; text-decoration: none; }

/* ===== TIMELINE ===== */
.timeline { list-style: none; position: relative; padding-left: 24px; }
.timeline::before {
  content: ''; position: absolute; left: 6px; top: 8px; bottom: 8px;
  width: 2px; background: var(--border);
}
.timeline li { position: relative; padding-bottom: 18px; }
.timeline li::before {
  content: ''; position: absolute; left: -21px; top: 8px;
  width: 10px; height: 10px; border-radius: 50%;
  background: var(--accent); border: 2px solid #fff; box-shadow: 0 0 0 2px var(--accent);
}
.timeline .tl-title { font-weight: 600; color: var(--primary); }
.timeline .tl-meta { font-size: 13px; color: var(--text-light); }

/* ===== NEWS / PRESENTATIONS ===== */
.news-list { list-style: none; }
.news-item {
  padding: 16px 0; border-bottom: 1px solid var(--bg-light);
  display: flex; gap: 16px; align-items: flex-start;
}
.news-item:last-child { border-bottom: none; }
.news-date {
  flex-shrink: 0; width: 90px; font-size: 13px; font-weight: 600;
  color: var(--accent); padding-top: 2px;
}
.news-content { flex: 1; }
.news-content .news-title { font-weight: 600; color: var(--primary); margin-bottom: 2px; }
.news-content .news-detail { font-size: 14px; color: var(--text-light); }
.news-tag {
  display: inline-block; font-size: 11px; padding: 1px 8px;
  border-radius: 4px; font-weight: 600; margin-right: 6px; vertical-align: middle;
}
.news-tag.talk { background: #e8f4fd; color: #2980b9; }
.news-tag.paper { background: #e8f8e8; color: #27ae60; }
.news-tag.award { background: #fef5e7; color: #e67e22; }
.news-tag.course { background: #fde8f0; color: #c0392b; }

/* ===== HONORS ===== */
.honors-list { list-style: none; }
.honors-item { padding: 10px 0; border-bottom: 1px solid var(--bg-light); }
.honors-item:last-child { border-bottom: none; }
.honors-item .honor-title { font-weight: 600; color: var(--primary); }
.honors-item .honor-meta { font-size: 13px; color: var(--text-light); }

/* ===== GALLERY ===== */
.gallery-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 20px; }
.gallery-item {
  border-radius: 10px; overflow: hidden; border: 1px solid var(--border);
  background: var(--bg-light); transition: transform 0.2s, box-shadow 0.2s;
}
.gallery-item:hover { transform: translateY(-3px); box-shadow: 0 6px 20px rgba(0,0,0,0.08); }
.gallery-item img { width: 100%; aspect-ratio: 4/3; object-fit: cover; display: block; }
.gallery-item .caption { padding: 12px 16px; }
.gallery-item .caption .caption-title { font-weight: 600; color: var(--primary); font-size: 14px; }
.gallery-item .caption .caption-date { font-size: 12px; color: var(--text-light); margin-top: 2px; }

/* ===== CONTACT ===== */
.contact-info {
  background: var(--bg-light); border-radius: 10px; padding: 24px; border: 1px solid var(--border);
}
.contact-info p { margin-bottom: 4px; font-size: 14px; }

/* ===== FOOTER ===== */
.footer {
  text-align: center; padding: 24px; font-size: 13px;
  color: var(--text-light); border-top: 1px solid var(--border); margin-top: 20px;
}

/* ===== PLACEHOLDER ===== */
.placeholder-msg {
  background: var(--bg-light); border: 2px dashed var(--border); border-radius: 10px;
  padding: 40px; text-align: center; color: var(--text-light);
}

/* ===== SERVICE LIST ===== */
.service-journals {
  column-count: 2; column-gap: 24px; list-style: none;
}
.service-journals li {
  padding: 4px 0; font-size: 14px; break-inside: avoid;
}

/* ===== RESPONSIVE ===== */
@media (max-width: 768px) {
  .hamburger { display: flex; }
  .nav-links {
    display: none; position: absolute; top: var(--nav-height);
    left: 0; right: 0; background: var(--primary);
    flex-direction: column; padding: 12px; gap: 0;
    box-shadow: 0 4px 12px rgba(0,0,0,0.15);
  }
  .nav-links.open { display: flex; }
  .nav-links a { padding: 12px 16px; border-radius: 4px; }
  .page-wrapper { flex-direction: column; }
  .sidebar {
    width: 100%; position: relative; top: 0; max-height: none;
    padding: 30px 20px 20px; border-bottom: 1px solid var(--border);
  }
  .main-content { padding: 24px 20px 40px; border-left: none; }
  .profile-photo { width: 140px; height: 140px; }
  .research-areas { grid-template-columns: repeat(2, 1fr); }
  .gallery-grid { grid-template-columns: 1fr; }
  .news-item { flex-direction: column; gap: 4px; }
  .news-date { width: auto; }
  .service-journals { column-count: 1; }
}
@media (max-width: 480px) {
  .research-areas { grid-template-columns: 1fr; }
}