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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto,
    "Helvetica Neue", Arial, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: #1a1a1a;
  background: #fff;
  -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration: none; }
img, svg { display: block; max-width: 100%; }

/* ===========================
   Layout
   =========================== */
.container { max-width: 900px; margin: 0 auto; padding: 0 24px; }

/* ===========================
   Navigation
   =========================== */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.96);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid #e8e8e8;
}

.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 56px;
}

.nav-logo { font-size: 1rem; font-weight: 600; letter-spacing: -0.01em; color: #111; }
.nav-logo:hover { color: #1a56db; }

.nav-links { display: flex; gap: 32px; list-style: none; }

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: #555;
  transition: color 0.15s;
}

.nav-links a:hover,
.nav-links a.active { color: #111; }

/* ===========================
   Footer
   =========================== */
footer {
  border-top: 1px solid #e8e8e8;
  margin-top: 80px;
  padding: 32px 0;
  color: #888;
  font-size: 0.85rem;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.footer-links { display: flex; gap: 24px; list-style: none; }
.footer-links a { color: #888; transition: color 0.15s; }
.footer-links a:hover { color: #111; }

/* ===========================
   Home — hero
   =========================== */
.hero {
  padding: 72px 0 60px;
  border-bottom: 1px solid #ebebeb;
}

.hero-avatar {
  width: 288px;
  height: 288px;
  border-radius: 50%;
  background: linear-gradient(135deg, #3b82f6, #6366f1);
  color: #fff;
  font-size: 1.75rem;
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 24px;
  user-select: none;
}

.hero h1 {
  font-size: 2rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
  margin-bottom: 12px;
}

.hero p {
  font-size: 1.05rem;
  color: #555;
  max-width: 560px;
  line-height: 1.7;
  margin-bottom: 28px;
}

.btn-row { display: flex; gap: 12px; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 9px 20px;
  border-radius: 8px;
  font-size: 0.875rem;
  font-weight: 500;
  transition: background 0.15s, border-color 0.15s, color 0.15s;
  cursor: pointer;
}

.btn-primary { background: #1a56db; color: #fff; border: 1px solid #1a56db; }
.btn-primary:hover { background: #1648c0; border-color: #1648c0; }
.btn-outline { background: transparent; color: #333; border: 1px solid #d1d5db; }
.btn-outline:hover { border-color: #9ca3af; color: #111; }

/* ===========================
   Home — preview sections
   =========================== */
.home-section {
  padding: 52px 0;
  border-bottom: 1px solid #ebebeb;
}

.home-section:last-child { border-bottom: none; }

.section-header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  margin-bottom: 28px;
}

.section-header h2 { font-size: 1.1rem; font-weight: 600; }

.view-all { font-size: 0.85rem; color: #1a56db; font-weight: 500; transition: color 0.15s; }
.view-all:hover { color: #1340a0; }

/* ===========================
   Cards (travel preview on home)
   =========================== */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 20px;
}

.card {
  border: 1px solid #e8e8e8;
  border-radius: 12px;
  overflow: hidden;
  transition: box-shadow 0.2s, border-color 0.2s;
}

.card:hover { box-shadow: 0 4px 20px rgba(0,0,0,0.08); border-color: #d0d0d0; }

.card-cover { width: 100%; aspect-ratio: 3/2; object-fit: cover; background: #e8e8e8; }

.card-body { padding: 14px 16px 18px; }

.card-meta { font-size: 0.72rem; color: #999; text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 4px; }

.card-title { font-size: 0.92rem; font-weight: 600; color: #111; line-height: 1.35; margin-bottom: 5px; }
.card:hover .card-title { color: #1a56db; }

.card-excerpt {
  font-size: 0.8rem;
  color: #666;
  line-height: 1.5;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

/* ===========================
   Publication list
   =========================== */
.pub-list { display: flex; flex-direction: column; gap: 14px; }

.pub-item {
  display: flex;
  gap: 12px;
  padding: 14px 16px;
  border: 1px solid #e8e8e8;
  border-radius: 10px;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.pub-item:hover { border-color: #d0d0d0; box-shadow: 0 2px 10px rgba(0,0,0,0.06); }

.pub-badge {
  flex-shrink: 0;
  font-size: 0.68rem;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 99px;
  margin-top: 2px;
  height: fit-content;
  white-space: nowrap;
}

.badge-journal    { background: #eff6ff; color: #1a56db; }
.badge-conference { background: #f0fdf4; color: #166534; }
.badge-preprint   { background: #fffbeb; color: #92400e; }

.pub-title { font-size: 0.88rem; font-weight: 600; color: #111; line-height: 1.4; margin-bottom: 3px; }
.pub-authors { font-size: 0.78rem; color: #666; margin-bottom: 2px; }
.pub-venue { font-size: 0.78rem; color: #888; font-style: italic; }

/* ===========================
   Page header (travel & academic)
   =========================== */
.page-header {
  padding: 60px 0 40px;
  border-bottom: 1px solid #ebebeb;
  margin-bottom: 48px;
}

.page-header h1 { font-size: 1.9rem; font-weight: 700; letter-spacing: -0.02em; margin-bottom: 10px; }
.page-header p  { font-size: 1rem; color: #666; max-width: 520px; line-height: 1.65; }

/* ===========================
   Travel page — trips
   =========================== */
.trip { margin-bottom: 68px; }

.trip-header { display: flex; align-items: baseline; gap: 16px; margin-bottom: 6px; }
.trip-header h2 { font-size: 1.2rem; font-weight: 700; letter-spacing: -0.01em; }
.trip-date { font-size: 0.8rem; color: #999; font-style: italic; }

.trip-location {
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: #aaa;
  margin-bottom: 8px;
}

.trip-desc { font-size: 0.875rem; color: #666; line-height: 1.65; max-width: 600px; margin-bottom: 18px; }

/* Photo grid */
.photo-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 6px;
}

.photo-grid img {
  width: 100%;
  aspect-ratio: 4/3;
  object-fit: cover;
  border-radius: 6px;
  cursor: pointer;
  transition: opacity 0.15s, transform 0.2s;
}

.photo-grid img:hover { opacity: 0.88; transform: scale(1.01); }

/* Lightbox */
.lightbox {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.90);
  z-index: 500;
  align-items: center;
  justify-content: center;
  padding: 20px;
}

.lightbox.open { display: flex; }

.lightbox img {
  max-width: 100%;
  max-height: calc(100vh - 80px);
  object-fit: contain;
  border-radius: 4px;
}

.lb-close {
  position: fixed;
  top: 14px;
  right: 18px;
  color: rgba(255,255,255,0.8);
  font-size: 2rem;
  cursor: pointer;
  background: none;
  border: none;
  line-height: 1;
  transition: color 0.1s;
}

.lb-close:hover { color: #fff; }

.lb-prev, .lb-next {
  position: fixed;
  top: 50%;
  transform: translateY(-50%);
  color: rgba(255,255,255,0.75);
  font-size: 2.2rem;
  cursor: pointer;
  background: none;
  border: none;
  padding: 8px 14px;
  user-select: none;
  transition: color 0.1s;
}

.lb-prev { left: 6px; }
.lb-next { right: 6px; }
.lb-prev:hover, .lb-next:hover { color: #fff; }

/* ===========================
   Academic page
   =========================== */
.academic-section { margin-bottom: 60px; }

.academic-section h2 {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: 22px;
  padding-bottom: 10px;
  border-bottom: 2px solid #f0f0f0;
}

/* Projects */
.projects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 14px;
}

.project-card {
  border: 1px solid #e8e8e8;
  border-radius: 10px;
  padding: 18px;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.project-card:hover { border-color: #d0d0d0; box-shadow: 0 2px 10px rgba(0,0,0,0.06); }

.project-top { display: flex; align-items: flex-start; justify-content: space-between; gap: 10px; margin-bottom: 8px; }
.project-title { font-size: 0.88rem; font-weight: 600; color: #111; line-height: 1.35; }

.project-status {
  flex-shrink: 0;
  font-size: 0.68rem;
  font-weight: 700;
  padding: 3px 8px;
  border-radius: 99px;
}

.status-active    { background: #f0fdf4; color: #166534; }
.status-completed { background: #f3f4f6; color: #6b7280; }

.project-desc { font-size: 0.8rem; color: #666; line-height: 1.55; margin-bottom: 12px; }

.project-tags { display: flex; flex-wrap: wrap; gap: 5px; }

.tag { font-size: 0.68rem; padding: 2px 8px; background: #f3f4f6; color: #555; border-radius: 99px; }

/* Publications */
.year-group { margin-bottom: 36px; }

.year-label {
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: #bbb;
  margin-bottom: 14px;
}

.pub-list-full { display: flex; flex-direction: column; gap: 12px; }

.pub-full {
  padding: 16px 18px;
  border: 1px solid #e8e8e8;
  border-radius: 10px;
  transition: border-color 0.15s, box-shadow 0.15s;
}

.pub-full:hover { border-color: #d0d0d0; box-shadow: 0 2px 10px rgba(0,0,0,0.06); }

.pub-full-top { display: flex; gap: 10px; margin-bottom: 6px; align-items: flex-start; }

.pub-full-title { font-size: 0.9rem; font-weight: 600; color: #111; line-height: 1.4; }
.pub-full-authors { font-size: 0.8rem; color: #666; margin-bottom: 2px; }
.pub-full-venue { font-size: 0.8rem; color: #888; font-style: italic; margin-bottom: 8px; }

.pub-doi { font-size: 0.75rem; color: #aaa; margin-bottom: 8px; }

details.abstract-toggle { margin-top: 4px; }

details.abstract-toggle > summary {
  font-size: 0.78rem;
  font-weight: 600;
  color: #1a56db;
  cursor: pointer;
  list-style: none;
}

details.abstract-toggle > summary::-webkit-details-marker { display: none; }

details.abstract-toggle > summary::before {
  content: "▸ ";
}

details.abstract-toggle[open] > summary::before {
  content: "▾ ";
}

.abstract-text {
  margin-top: 10px;
  font-size: 0.8rem;
  color: #555;
  line-height: 1.65;
  border-left: 2px solid #e8e8e8;
  padding-left: 12px;
}

/* Contact */
.contact-block {
  background: #f9fafb;
  border-radius: 12px;
  padding: 28px 32px;
  margin-bottom: 60px;
}

.contact-block p { font-size: 0.9rem; color: #555; line-height: 1.7; }
.contact-block a { color: #1a56db; font-weight: 500; }
.contact-block a:hover { text-decoration: underline; }

/* ===========================
   Responsive
   =========================== */
@media (max-width: 640px) {
  .hero h1   { font-size: 1.6rem; }
  .hero p    { font-size: 0.95rem; }
  .photo-grid { grid-template-columns: repeat(2, 1fr); }
  .nav-links { gap: 20px; }
  .projects-grid { grid-template-columns: 1fr; }
  .cards-grid    { grid-template-columns: 1fr; }
}