/* ======================================
   WENYANG QIAN — PERSONAL SITE
   Aesthetic: Refined academic minimalism
====================================== */

@import url('https://fonts.googleapis.com/css2?family=EB+Garamond:ital,wght@0,400;0,600;1,400&family=DM+Mono:wght@300;400&family=Instrument+Sans:wght@400;500;600&display=swap');

/* --- Variables --- */
:root {
  --bg:           #f5f3ef;
  --surface:      #ffffff;
  --border:       #dedad4;
  --text:         #1a1814;
  --muted:        #7a756c;
  --accent:       #2b4aab;
  --accent-light: #eaeefd;
  --accent2:      #8b2252;
  --mono:         'DM Mono', monospace;
  --serif:        'EB Garamond', Georgia, serif;
  --sans:         'Instrument Sans', sans-serif;
  --radius:       4px;
  --transition:   200ms ease;
}

/* --- Reset & Base --- */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  min-height: 100vh;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* --- Subtle grid background --- */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  background-image:
    linear-gradient(rgba(43,74,171,0.03) 1px, transparent 1px),
    linear-gradient(90deg, rgba(43,74,171,0.03) 1px, transparent 1px);
  background-size: 40px 40px;
  pointer-events: none;
  z-index: 0;
}

/* --- Layout --- */
.site-wrapper {
  position: relative;
  z-index: 1;
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 2rem;
}

/* --- Top Bar --- */
.topbar {
  display: flex;
  justify-content: flex-end;
  align-items: center;
  gap: 0.6rem;
  padding: 0.75rem 2rem;
  max-width: 1100px;
  margin: 0 auto;
  position: relative;
  z-index: 10;
}

.lang-toggle {
  font-family: var(--mono);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 0.3rem 0.8rem;
  border-radius: var(--radius);
  cursor: pointer;
  transition: var(--transition);
}
.lang-toggle:hover { border-color: var(--accent); color: var(--accent); }

.last-updated {
  font-family: var(--mono);
  font-size: 0.62rem;
  letter-spacing: 0.04em;
  color: var(--muted);
  opacity: 0.5;
}

/* --- Main Grid --- */
.main-grid {
  display: grid;
  grid-template-columns: 270px 1fr;
  gap: 4rem;
  padding: 2rem 0 6rem;
  align-items: start;
}
@media (max-width: 768px) {
  .main-grid {
    grid-template-columns: 1fr;
    gap: 2rem;
    padding: 1rem 0 4rem;
  }
}

/* --- Sidebar --- */
.sidebar { position: sticky; top: 3rem; }

@media (max-width: 768px) {
  /* On mobile: sidebar is normal flow, not sticky */
  .sidebar {
    position: static;
    display: flex;
    flex-direction: column;
    align-items: center;
    text-align: center;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
  }
  .sidebar .position { text-align: center; }
  .sidebar-meta { align-items: center; }
  .social-links { justify-content: center; }
  .profile-img-wrap { margin-left: auto; margin-right: auto; }
}

.profile-img-wrap {
  width: 138px;
  height: 138px;
  border-radius: 50%;
  overflow: hidden;
  margin-bottom: 1.5rem;
  border: 3px solid var(--border);
  background: var(--border);
  position: relative;
}
.profile-img-wrap::after {
  content: '';
  position: absolute;
  inset: -3px;
  border-radius: 50%;
  border: 1px solid var(--accent);
  opacity: 0.3;
}
.profile-img-wrap img { width: 100%; height: 100%; object-fit: cover; display: block; }

.sidebar h1 {
  font-family: var(--serif);
  font-size: 1.85rem;
  font-weight: 600;
  line-height: 1.2;
  margin-bottom: 0.4rem;
}

.sidebar .position {
  font-size: 0.84rem;
  color: var(--muted);
  line-height: 1.65;
  margin-bottom: 1.4rem;
}
.sidebar .position strong { display: block; color: var(--text); font-weight: 500; margin-bottom: 0.1rem; }

.sidebar-meta {
  border-top: 1px solid var(--border);
  padding-top: 1.1rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.meta-item {
  display: flex;
  align-items: flex-start;
  gap: 0.6rem;
  font-size: 0.81rem;
  color: var(--muted);
}
.meta-item i { width: 14px; margin-top: 3px; color: var(--accent); opacity: 0.7; flex-shrink: 0; }

.social-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.9rem;
  margin-top: 1.2rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}
.social-links a { color: var(--muted); font-size: 1.05rem; transition: var(--transition); }
.social-links a:hover { color: var(--accent); text-decoration: none; }

/* --- Content --- */
.content-area { min-width: 0; }

/* --- Tabs nav --- */
.tab-nav {
  display: flex;
  border-bottom: 1px solid var(--border);
  margin-bottom: 2.5rem;
  overflow-x: auto;
  /* hide scrollbar on all browsers */
  scrollbar-width: none;
  -ms-overflow-style: none;
}
.tab-nav::-webkit-scrollbar { display: none; }

.tab-btn {
  font-family: var(--mono);
  font-size: 0.82rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  color: var(--muted);
  padding: 0.75rem 1.2rem;
  cursor: pointer;
  margin-bottom: -1px;
  transition: var(--transition);
  white-space: nowrap;
}
.tab-btn:hover { color: var(--text); }
.tab-btn.active { color: var(--accent); border-bottom-color: var(--accent); }

/* --- Tab pane --- */
.tab-pane { display: none; animation: fadeIn 0.2s ease; }
.tab-pane.active { display: block; }
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(5px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* --- Loading indicator --- */
.tab-loading {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  color: var(--muted);
  font-family: var(--mono);
  font-size: 0.78rem;
  padding: 2rem 0;
}
.tab-loading::before {
  content: '';
  width: 12px; height: 12px;
  border: 2px solid var(--border);
  border-top-color: var(--accent);
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* --- Section label --- */
.section-label {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1rem;
}

/* ======================================
   ABOUT TAB
====================================== */
.about-text p {
  font-family: var(--serif);
  font-size: 1.15rem;
  line-height: 1.8;
  color: var(--text);
  margin-bottom: 1.2rem;
}
.about-text p em { font-style: italic; }

.research-interests { margin-top: 2.5rem; }
.tags { display: flex; flex-wrap: wrap; gap: 0.5rem; }
.tag {
  font-size: 0.79rem;
  padding: 0.28rem 0.8rem;
  border-radius: 2px;
  border: 1px solid var(--border);
  color: var(--muted);
  background: var(--surface);
}
.tag.primary {
  background: var(--accent-light);
  border-color: rgba(43,74,171,0.2);
  color: var(--accent);
}

/* ======================================
   CV TAB
====================================== */
.cv-section { margin-bottom: 2.5rem; }

.cv-section-title {
  font-family: var(--mono);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 1.1rem;
  padding-bottom: 0.55rem;
  border-bottom: 1px solid var(--border);
}

.cv-item {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.2rem 1rem;
  margin-bottom: 1.25rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}
.cv-item:last-child { border-bottom: none; margin-bottom: 0; padding-bottom: 0; }

.cv-item-title { font-size: 0.95rem; font-weight: 600; color: var(--text); grid-column: 1; }
.cv-item-date {
  font-family: var(--mono);
  font-size: 0.78rem;
  color: var(--muted);
  white-space: nowrap;
  grid-column: 2; grid-row: 1;
}
.cv-item-sub { font-size: 0.87rem; color: var(--muted); grid-column: 1 / -1; }
.cv-item-note { font-size: 0.84rem; color: var(--muted); font-style: italic; grid-column: 1 / -1; margin-top: 0.15rem; }

.award-list { list-style: none; display: flex; flex-direction: column; gap: 0.6rem; }
.award-item {
  display: flex;
  align-items: baseline;
  gap: 0.8rem;
  font-size: 0.84rem;
  padding-bottom: 0.6rem;
  border-bottom: 1px solid var(--border);
}
.award-item:last-child { border-bottom: none; }
.award-year {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  flex-shrink: 0;
  min-width: 4rem;
}

.grant-item {
  margin-bottom: 1.25rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--border);
}
.grant-item:last-child { border-bottom: none; margin-bottom: 0; padding-bottom: 0; }
.grant-header {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 0.5rem;
  margin-bottom: 0.2rem;
}
.grant-title { font-size: 0.88rem; font-weight: 600; color: var(--text); }
.grant-amount {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  white-space: nowrap;
}
.grant-meta { font-size: 0.81rem; color: var(--muted); }

/* ======================================
   PUBLICATIONS TAB
====================================== */
.pub-stats {
  font-family: var(--mono);
  font-size: 0.77rem;
  color: var(--muted);
  margin-bottom: 2rem;
  padding: 0.7rem 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  display: inline-flex;
  align-items: center;
  gap: 1.2rem;
}
.pub-stats a { font-family: var(--mono); font-size: 0.73rem; }

.pub-section { margin-bottom: 2.5rem; }

.pub-list { list-style: none; counter-reset: pub-counter; }
.pub-item {
  counter-increment: pub-counter;
  display: grid;
  grid-template-columns: 2rem 1fr;
  gap: 0 0.6rem;
  margin-bottom: 1.1rem;
  padding-bottom: 1.1rem;
  border-bottom: 1px solid var(--border);
}
.pub-item:last-child { border-bottom: none; }
.pub-item::before {
  content: counter(pub-counter);
  font-family: var(--mono);
  font-size: 0.68rem;
  color: var(--muted);
  padding-top: 0.2rem;
}
.pub-text { font-size: 0.93rem; line-height: 1.68; color: var(--text); }
.pub-text em { font-family: var(--serif); font-style: italic; font-size: 1rem; }
.pub-text strong { font-weight: 600; }
.pub-links { display: flex; flex-wrap: wrap; gap: 0.4rem; margin-top: 0.35rem; }
.pub-link {
  font-family: var(--mono);
  font-size: 0.71rem;
  background: var(--accent-light);
  color: var(--accent);
  padding: 0.1rem 0.45rem;
  border-radius: 2px;
  white-space: nowrap;
}
.pub-link:hover { background: var(--accent); color: #fff; text-decoration: none; }
.pub-link.doi { background: #eef6ee; color: #2a6b2a; }
.pub-link.doi:hover { background: #2a6b2a; color: #fff; }

/* ======================================
   TALKS TAB
====================================== */
.talks-filter {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  margin-bottom: 1.8rem;
}
.filter-btn {
  font-family: var(--mono);
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 0.25rem 0.65rem;
  border-radius: 2px;
  cursor: pointer;
  transition: var(--transition);
}
.filter-btn:hover, .filter-btn.active {
  background: var(--accent-light);
  border-color: rgba(43,74,171,0.3);
  color: var(--accent);
}

.talk-item {
  display: grid;
  grid-template-columns: 4rem 1fr;
  gap: 0 0.9rem;
  padding: 0.9rem 0;
  border-bottom: 1px solid var(--border);
}
.talk-item:last-child { border-bottom: none; }
.talk-item[data-type="invited"] .talk-year { color: var(--accent2); }

.talk-year {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--muted);
  padding-top: 0.15rem;
  line-height: 1.4;
}
.talk-badge {
  display: inline-block;
  font-family: var(--mono);
  font-size: 0.62rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  padding: 0.1rem 0.4rem;
  border-radius: 2px;
  margin-bottom: 0.3rem;
}
.badge-invited    { background: #fdf0f5; color: var(--accent2); border: 1px solid #f5d0e0; }
.badge-plenary    { background: #fff5e6; color: #b55a00; border: 1px solid #fcd9a5; }
.badge-contributed{ background: #f0f4ff; color: var(--accent); border: 1px solid #c5d3f5; }
.badge-poster     { background: #f2f9f2; color: #2a6b2a; border: 1px solid #bde0bd; }
.badge-seminar    { background: #f5f3ef; color: var(--muted); border: 1px solid var(--border); }

.talk-title { font-size: 0.93rem; font-weight: 500; color: var(--text); line-height: 1.45; margin-bottom: 0.2rem; }
.talk-venue { font-size: 0.84rem; color: var(--muted); }
.talk-venue em { font-style: normal; color: var(--text); }

/* ======================================
   TEACHING TAB
====================================== */
.teaching-item {
  padding: 1.1rem 0;
  border-bottom: 1px solid var(--border);
}
.teaching-item:last-child { border-bottom: none; }
.teaching-item-title { font-size: 0.96rem; font-weight: 600; color: var(--text); margin-bottom: 0.2rem; }
.teaching-item-meta {
  font-family: var(--mono);
  font-size: 0.76rem;
  color: var(--accent);
  margin-bottom: 0.35rem;
}
.teaching-item-desc { font-size: 0.88rem; color: var(--muted); }
.teaching-item-desc em { font-style: italic; color: var(--accent2); }

/* ======================================
   RESEARCH TAB
====================================== */
.research-block {
  padding: 1.5rem 0;
  border-bottom: 1px solid var(--border);
}
.research-block-header {
  display: flex;
  align-items: baseline;
  gap: 0.9rem;
  margin-bottom: 0.8rem;
}
.research-block-num {
  font-family: var(--mono);
  font-size: 0.72rem;
  color: var(--accent);
  opacity: 0.5;
  flex-shrink: 0;
}
.research-block-title {
  font-family: var(--serif);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text);
}
.research-block-body p {
  font-size: 0.91rem;
  line-height: 1.72;
  color: var(--text);
  margin-bottom: 0.9rem;
}
.research-tags { display: flex; flex-wrap: wrap; gap: 0.4rem; }

/* ======================================
   JOIN US TAB
====================================== */
.joinus-section { margin-bottom: 2.5rem; }
.joinus-section p {
  font-family: var(--serif);
  font-size: 1.1rem;
  line-height: 1.8;
  color: var(--text);
  margin-bottom: 1rem;
}
.joinus-positions {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  margin-top: 1.5rem;
}
.joinus-position {
  padding: 1.1rem 1.3rem;
  background: var(--surface);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
}
.joinus-position-title {
  font-size: 0.93rem;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 0.35rem;
}
.joinus-position-desc { font-size: 0.85rem; color: var(--muted); line-height: 1.6; }

/* ======================================
   QUICK LINKS (sidebar footer)
====================================== */
.quick-links {
  margin-top: 1.2rem;
  padding-top: 1.2rem;
  border-top: 1px solid var(--border);
}
.quick-links-label {
  font-family: var(--mono);
  font-size: 0.66rem;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--muted);
  margin-bottom: 0.5rem;
}
.quick-links-list {
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
}
.quick-links-list a {
  font-size: 0.8rem;
  color: var(--muted);
  transition: var(--transition);
}
.quick-links-list a:hover { color: var(--accent); text-decoration: none; }

/* ======================================
   LANG hide/show
====================================== */
html[lang="en"] .lang-zh { display: none !important; }
html[lang="zh"] .lang-en { display: none !important; }