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

:root {
  --bg:          #f8f7f4;
  --surface:     #ffffff;
  --border:      #e4e2dc;
  --text:        #1a1a1a;
  --text-muted:  #6b6860;
  --accent:      #2d6a6a;
  --accent-light:#e8f4f4;
  --accent-dim:  #4a9090;
  --mono:        'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
  --sans:        'Inter', 'Helvetica Neue', Arial, sans-serif;
  --r:           6px;
  --max-w:       900px;
  --nav-h:       60px;
}

html { scroll-behavior: smooth; scroll-padding-top: var(--nav-h); }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
  /* Subtle dot grid background */
  background-image: radial-gradient(circle, #c8c5bc 1px, transparent 1px);
  background-size: 28px 28px;
  background-attachment: fixed;
}

/* ─── Nav ────────────────────────────────────────────────────────────── */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--nav-h);
  background: rgba(248, 247, 244, 0.92);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  padding: 0 2rem;
}

.nav-inner {
  max-width: var(--max-w);
  width: 100%;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-family: var(--mono);
  font-size: 0.85rem;
  color: var(--accent);
  letter-spacing: 0.05em;
  text-decoration: none;
  font-weight: 600;
}

.nav-brand span { color: var(--text-muted); }

.nav-links {
  display: flex;
  gap: 2rem;
  list-style: none;
}

.nav-links a {
  font-size: 0.85rem;
  color: var(--text-muted);
  text-decoration: none;
  letter-spacing: 0.03em;
  transition: color 0.2s;
  font-weight: 500;
}

.nav-links a:hover { color: var(--accent); }

/* Sub-page nav (papers.html, research.html) */
.nav-back {
  font-family: var(--mono);
  font-size: 0.82rem;
  color: var(--text-muted);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.4rem;
  transition: color 0.2s;
}
.nav-back:hover { color: var(--accent); }
.nav-back .brand-dot { color: var(--accent); }

.nav-page-title {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
}

/* ─── Layout ─────────────────────────────────────────────────────────── */
main {
  max-width: var(--max-w);
  margin: 0 auto;
  padding: 0 2rem 4rem;
}

section {
  margin-top: 5rem;
}

/* ─── Hero / About ───────────────────────────────────────────────────── */
#about {
  margin-top: 4rem;
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 3rem;
  align-items: start;
}

.profile-col {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  min-width: 160px;
}

.avatar-wrap {
  position: relative;
  width: 130px;
  height: 130px;
}

.avatar-wrap::before {
  content: '';
  position: absolute;
  inset: -4px;
  border-radius: 50%;
  border: 2px dashed var(--accent);
  opacity: 0.4;
  animation: spin 20s linear infinite;
}

.avatar-wrap img {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  object-fit: cover;
  display: block;
  position: relative;
  z-index: 1;
}

.avatar-placeholder {
  width: 100%;
  height: 100%;
  border-radius: 50%;
  background: var(--accent-light);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 2.5rem;
  position: relative;
  z-index: 1;
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to   { transform: rotate(360deg); }
}

.profile-name {
  text-align: center;
}

.profile-name h1 {
  font-size: 1.05rem;
  font-weight: 700;
  line-height: 1.3;
}

.profile-name .name-zh {
  font-family: var(--mono);
  font-size: 0.75rem;
  color: var(--accent);
  display: block;
  margin-top: 2px;
}

.tagline {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  text-align: center;
  letter-spacing: 0.02em;
}

.social-links {
  display: flex;
  gap: 0.6rem;
  flex-wrap: wrap;
  justify-content: center;
}

.social-links a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.2s;
  font-size: 0.78rem;
  padding: 4px 8px;
  border: 1px solid var(--border);
  border-radius: var(--r);
  background: var(--surface);
  font-family: var(--mono);
}

.social-links a:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
}

.social-links a svg {
  width: 14px;
  height: 14px;
  vertical-align: middle;
}

.academic-links {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
  width: 100%;
}

.academic-links a {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.78rem;
  color: var(--text-muted);
  text-decoration: none;
  font-family: var(--mono);
  padding: 5px 8px;
  border-radius: var(--r);
  transition: all 0.2s;
}

.academic-links a:hover {
  color: var(--accent);
  background: var(--accent-light);
}

.cv-link {
  display: inline-flex !important;
  align-items: center;
  gap: 0.4rem;
  background: var(--accent) !important;
  color: #fff !important;
  padding: 6px 12px !important;
  border-radius: var(--r);
  font-size: 0.78rem;
  text-decoration: none;
  font-family: var(--mono);
  transition: background 0.2s !important;
  margin-top: 4px;
}

.cv-link:hover { background: var(--accent-dim) !important; }

/* ─── About Content ──────────────────────────────────────────────────── */
.about-col {}

.section-label {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--accent);
  letter-spacing: 0.12em;
  text-transform: uppercase;
  margin-bottom: 1rem;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.section-label::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

h2.section-title {
  font-size: 1.7rem;
  font-weight: 700;
  line-height: 1.2;
  margin-bottom: 1.2rem;
}

.bio-text {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.8;
  margin-bottom: 1.5rem;
}

.interests {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--text-muted);
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
}

.interests span {
  background: var(--accent-light);
  color: var(--accent);
  padding: 2px 10px;
  border-radius: 20px;
  border: 1px solid rgba(45,106,106,0.15);
}

/* ─── Section Headers ────────────────────────────────────────────────── */
.section-header {
  margin-bottom: 2rem;
}

/* ─── News ───────────────────────────────────────────────────────────── */
.news-list {
  display: flex;
  flex-direction: column;
  gap: 0;
}

.news-item {
  display: grid;
  grid-template-columns: 90px 1fr;
  gap: 1rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
  align-items: baseline;
}

.news-item:last-child { border-bottom: none; }

.news-date {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  white-space: nowrap;
  padding-top: 2px;
  font-weight: 600;
}

.news-text {
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.7;
}

.news-text a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid rgba(45,106,106,0.3);
  transition: border-color 0.2s;
}

.news-text a:hover { border-color: var(--accent); }

/* ─── Publications ───────────────────────────────────────────────────── */
.pub-filters {
  display: flex;
  gap: 0.5rem;
  flex-wrap: wrap;
  margin-bottom: 1.5rem;
}

.filter-btn {
  font-family: var(--mono);
  font-size: 0.72rem;
  padding: 4px 12px;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--surface);
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.2s;
}

.filter-btn:hover, .filter-btn.active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.pub-list {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.pub-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 1.2rem 1.4rem;
  transition: box-shadow 0.2s, border-color 0.2s;
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  align-items: start;
}

.pub-card:hover {
  box-shadow: 0 2px 16px rgba(0,0,0,0.07);
  border-color: var(--accent);
}

.pub-year-badge {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--accent);
  background: var(--accent-light);
  padding: 2px 8px;
  border-radius: 4px;
  white-space: nowrap;
  margin-top: 2px;
}

.pub-title {
  font-size: 0.95rem;
  font-weight: 600;
  line-height: 1.4;
  margin-bottom: 0.3rem;
}

.pub-title a {
  color: var(--text);
  text-decoration: none;
  transition: color 0.2s;
}

.pub-title a:hover { color: var(--accent); }

.pub-authors {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: 0.25rem;
}

.pub-venue {
  font-size: 0.8rem;
  color: var(--accent-dim);
  font-style: italic;
  margin-bottom: 0.5rem;
}

.pub-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
  margin-bottom: 0.6rem;
}

.pub-tag {
  font-family: var(--mono);
  font-size: 0.65rem;
  padding: 1px 8px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--text-muted);
}

.pub-links {
  display: flex;
  gap: 0.5rem;
}

.pub-link {
  font-family: var(--mono);
  font-size: 0.7rem;
  padding: 3px 10px;
  border: 1px solid var(--border);
  border-radius: 3px;
  color: var(--text-muted);
  text-decoration: none;
  transition: all 0.2s;
}

.pub-link:hover {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
}

.pub-link-demo {
  color: var(--accent);
  border-color: var(--accent);
  background: var(--accent-light);
}
.pub-link-demo:hover {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

/* ─── Research ───────────────────────────────────────────────────────── */
.research-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.2rem;
}

.research-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 1.4rem;
  transition: box-shadow 0.2s, border-color 0.2s, transform 0.2s;
}

.research-card:hover {
  box-shadow: 0 4px 20px rgba(45,106,106,0.1);
  border-color: var(--accent);
  transform: translateY(-2px);
}

.research-icon {
  font-size: 1.5rem;
  margin-bottom: 0.8rem;
  color: var(--accent);
}

.research-title {
  font-size: 0.95rem;
  font-weight: 700;
  margin-bottom: 0.7rem;
  line-height: 1.3;
}

.research-desc {
  font-size: 0.83rem;
  color: var(--text-muted);
  line-height: 1.7;
  margin-bottom: 0.8rem;
}

.research-tags {
  display: flex;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.research-tag {
  font-family: var(--mono);
  font-size: 0.65rem;
  padding: 2px 8px;
  background: var(--accent-light);
  color: var(--accent);
  border-radius: 3px;
}

.research-demo-link {
  display: inline-block;
  margin-top: 0.8rem;
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--accent);
  text-decoration: none;
  border: 1px solid var(--accent);
  padding: 3px 10px;
  border-radius: 3px;
  transition: all 0.2s;
}
.research-demo-link:hover {
  background: var(--accent);
  color: #fff;
}

/* ─── CV / Talks ─────────────────────────────────────────────────────── */
.cv-cta {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 2rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.cv-cta-text h3 {
  font-size: 1rem;
  margin-bottom: 0.3rem;
}

.cv-cta-text p {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--accent);
  color: #fff;
  padding: 8px 18px;
  border-radius: var(--r);
  text-decoration: none;
  font-size: 0.85rem;
  font-family: var(--mono);
  transition: background 0.2s;
  white-space: nowrap;
}

.btn-primary:hover { background: var(--accent-dim); }

/* ─── Footer ─────────────────────────────────────────────────────────── */
footer {
  margin-top: 6rem;
  border-top: 1px solid var(--border);
  padding: 2rem;
  text-align: center;
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--text-muted);
}

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

/* ─── Responsive ─────────────────────────────────────────────────────── */
@media (max-width: 700px) {
  #about {
    grid-template-columns: 1fr;
    gap: 2rem;
  }
  .profile-col { flex-direction: row; flex-wrap: wrap; gap: 1rem; }
  .profile-name, .tagline { text-align: left; }
  .social-links { justify-content: flex-start; }
  .research-grid { grid-template-columns: 1fr; }
  .pub-card { grid-template-columns: 1fr; }
  .cv-cta { flex-direction: column; align-items: flex-start; }
  .nav-links { gap: 1rem; }
}

@media (max-width: 480px) {
  nav { padding: 0 1rem; }
  main { padding: 0 1rem 4rem; }
}

/* ─── Beyond Research ────────────────────────────────────────────────── */
.beyond-interests {
  display: flex;
  gap: 1rem;
  flex-wrap: wrap;
  margin-bottom: 2rem;
}

.beyond-interest-card {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r);
  padding: 0.6rem 1.1rem;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-muted);
  transition: all 0.2s;
}

.beyond-interest-card:hover {
  border-color: var(--accent);
  color: var(--accent);
  background: var(--accent-light);
}

.beyond-interest-card .int-icon { font-size: 1.1rem; }

/* ─── Travel Map ─────────────────────────────────────────────────────── */
.travel-map-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r);
  overflow: hidden;
  margin-bottom: 1.5rem;
}

.travel-map-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.4rem;
  border-bottom: 1px solid var(--border);
}

.travel-stats {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--text-muted);
}

#travel-map {
  height: 280px;
  width: 100%;
  z-index: 0;
}

.race-map-wrap {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--r);
  overflow: hidden;
}

.race-map-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 1.4rem;
  border-bottom: 1px solid var(--border);
}

.itra-link {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  text-decoration: none;
  transition: opacity 0.2s;
}
.itra-link:hover { opacity: 0.7; }

#race-map {
  height: 320px;
  width: 100%;
  z-index: 0;
}

/* Leaflet popup override */
.leaflet-popup-content-wrapper {
  border-radius: var(--r) !important;
  box-shadow: 0 4px 20px rgba(0,0,0,0.12) !important;
  font-family: var(--sans) !important;
}
.leaflet-popup-content { margin: 10px 14px !important; }
.race-popup-name { font-weight: 600; font-size: 0.85rem; margin-bottom: 4px; }
.race-popup-meta { font-size: 0.75rem; color: var(--text-muted); }
.race-popup-score { font-family: var(--mono); color: var(--accent); font-size: 0.75rem; margin-top: 4px; }

.race-list {
  display: flex;
  flex-direction: column;
  max-height: 272px;   /* ~5 rows */
  overflow-y: auto;
  /* slim scrollbar */
  scrollbar-width: thin;
  scrollbar-color: var(--border) transparent;
}
.race-list::-webkit-scrollbar { width: 4px; }
.race-list::-webkit-scrollbar-track { background: transparent; }
.race-list::-webkit-scrollbar-thumb { background: var(--border); border-radius: 2px; }

.race-item {
  display: grid;
  grid-template-columns: 80px 1fr auto auto;
  gap: 0.8rem;
  align-items: center;
  padding: 0.8rem 1.4rem;
  border-top: 1px solid var(--border);
  font-size: 0.83rem;
  transition: background 0.15s;
  cursor: pointer;
}

.race-item:hover { background: var(--accent-light); }

.race-item-date {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
}

.race-item-name { font-weight: 500; }
.race-item-name small { display: block; font-size: 0.75rem; color: var(--text-muted); font-weight: 400; }

.race-item-dist {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--text-muted);
  white-space: nowrap;
  text-align: right;
}

.race-item-time {
  font-family: var(--mono);
  font-size: 0.72rem;
  text-align: right;
  white-space: nowrap;
  color: var(--accent);
  font-weight: 600;
}

.race-item-time.dnf { color: var(--text-muted); font-weight: 400; }

@media (max-width: 600px) {
  .race-item { grid-template-columns: 70px 1fr auto; }
  .race-item-dist { display: none; }
}

.view-all-link {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
  transition: opacity 0.2s;
}
.view-all-link:hover { opacity: 0.7; }

/* ─── Talks preview (homepage) ───────────────────────────────────────── */
.talk-preview-item {
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
}
.talk-preview-item:last-child { border-bottom: none; }

.talk-preview-meta {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  flex-wrap: wrap;
  margin-bottom: 0.35rem;
}
.talk-preview-event {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  font-weight: 600;
}
.talk-preview-year {
  font-family: var(--mono);
  font-size: 0.7rem;
  color: var(--text-muted);
}
.talk-preview-type {
  font-family: var(--mono);
  font-size: 0.62rem;
  padding: 1px 7px;
  border-radius: 3px;
  background: color-mix(in srgb, var(--accent) 10%, transparent);
  color: var(--accent);
}
.talk-preview-title {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.45;
  margin-bottom: 0.25rem;
}
.talk-preview-topic {
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--text-muted);
}

/* ─── Writing preview (homepage) ─────────────────────────────────────── */
.writing-preview-item {
  display: block;
  padding: 1rem 0;
  border-bottom: 1px solid var(--border);
  text-decoration: none;
  color: inherit;
  transition: background 0.15s, padding-left 0.15s;
}
.writing-preview-item:first-child { border-top: 1px solid var(--border); }
.writing-preview-item:hover { background: color-mix(in srgb, var(--accent) 4%, transparent); border-radius: var(--r); padding-left: 0.5rem; }
.writing-preview-meta {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  margin-bottom: 0.3rem;
  flex-wrap: wrap;
}
.writing-preview-date {
  font-family: var(--mono);
  font-size: 0.74rem;
  color: var(--text-muted);
  letter-spacing: 0.02em;
}
.writing-preview-tag {
  font-family: var(--mono);
  font-size: 0.68rem;
  padding: 0.1rem 0.45rem;
  border-radius: 3px;
  background: var(--accent-light);
  color: var(--accent);
  border: 1px solid color-mix(in srgb, var(--accent) 20%, transparent);
}
.writing-preview-title {
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text);
  line-height: 1.4;
  margin-bottom: 0.2rem;
}
.writing-preview-item:hover .writing-preview-title { color: var(--accent); }
.writing-preview-sub {
  font-size: 0.82rem;
  color: var(--text-muted);
  line-height: 1.5;
}

/* ─── Post links ─────────────────────────────────────────────────────── */
.pub-link-post {
  color: var(--accent) !important;
  border-color: color-mix(in srgb, var(--accent) 30%, transparent) !important;
}
.paper-post-link {
  display: inline-block;
  margin-top: 0.25rem;
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  text-decoration: none;
}
.paper-post-link:hover { text-decoration: underline; }

/* ─── Utility ────────────────────────────────────────────────────────── */
.hidden { display: none !important; }