/* ===========================================================
   Yuting Mou — Academic homepage
   Token system
   =========================================================== */
:root {
  /* Color */
  --bg:        #FAFAF8;
  --bg-panel:  #F3F1EC;
  --ink:       #1A2332;
  --ink-soft:  #5B6573;
  --line:      #E2E4E8;
  --accent:    #1E3A5F;   /* deep academic blue */
  --accent-soft: #2E5078;
  --gold:      #8C6D46;   /* warm bronze accent */
  --white:     #FFFFFF;

  /* Type */
  --font-display: 'Source Serif 4', 'Noto Serif SC', Georgia, serif;
  --font-body:    'Inter', 'Noto Sans SC', -apple-system, sans-serif;
  --font-mono:    'IBM Plex Mono', ui-monospace, SFMono-Regular, monospace;

  /* Layout */
  --sidebar-w: 280px;
  --content-max: 760px;
  --radius: 3px;
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color .15s ease, color .15s ease;
}
a:hover { border-bottom-color: var(--accent); }
a:focus-visible, button:focus-visible, input:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

img { max-width: 100%; display: block; }

/* ---------- Page shell ---------- */
.layout {
  display: flex;
  min-height: 100vh;
  max-width: 1180px;
  margin: 0 auto;
}

/* ---------- Sidebar ---------- */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  padding: 48px 28px 40px 0;
  position: sticky;
  top: 0;
  align-self: flex-start;
  height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
}

.sidebar-photo {
  width: 132px;
  height: 176px;
  object-fit: cover;
  border-radius: var(--radius);
  margin-bottom: 20px;
  border: 1px solid var(--line);
}

.sidebar-name {
  font-family: var(--font-display);
  font-size: 1.5rem;
  font-weight: 600;
  line-height: 1.25;
  margin: 0 0 2px;
  color: var(--ink);
}
.sidebar-name .zh { font-size: 1rem; color: var(--ink-soft); font-weight: 400; }

.sidebar-role {
  font-size: .92rem;
  color: var(--ink-soft);
  margin: 10px 0 18px;
  line-height: 1.55;
}
.sidebar-role a { color: var(--ink-soft); border-bottom: 1px dotted var(--line); }
.sidebar-role a:hover { color: var(--accent); border-bottom-color: var(--accent); }

.sidebar-contact {
  font-size: .85rem;
  color: var(--ink-soft);
  font-family: var(--font-mono);
  line-height: 1.7;
  margin-bottom: 22px;
  word-break: break-word;
}

.sidebar-links {
  display: flex;
  gap: 14px;
  margin-bottom: 32px;
  font-size: .85rem;
}

nav.sidebar-nav {
  border-top: 1px solid var(--line);
  padding-top: 18px;
  margin-top: auto;
}
.sidebar-nav .menu-label {
  font-size: .72rem;
  letter-spacing: .08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 10px;
  font-weight: 600;
}
.sidebar-nav a {
  display: block;
  padding: 7px 0;
  font-size: .94rem;
  color: var(--ink-soft);
  border-bottom: none;
}
.sidebar-nav a:hover { color: var(--accent); }
.sidebar-nav a.current {
  color: var(--accent);
  font-weight: 600;
  border-left: 2px solid var(--gold);
  padding-left: 10px;
  margin-left: -12px;
}

/* ---------- Main content ---------- */
.content {
  flex: 1;
  min-width: 0;
  padding: 48px 32px 80px 48px;
  max-width: 880px;
}

.page-title {
  font-family: var(--font-display);
  font-size: 2rem;
  font-weight: 600;
  margin: 0 0 6px;
  color: var(--ink);
}
.page-subtitle {
  color: var(--ink-soft);
  font-size: 1rem;
  margin: 0 0 36px;
}

section.block { margin-bottom: 44px; }

h2.section-head {
  font-family: var(--font-display);
  font-size: 1.3rem;
  font-weight: 600;
  color: var(--ink);
  margin: 0 0 18px;
  padding-bottom: 10px;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: baseline;
  gap: 10px;
}
h2.section-head::before {
  content: '';
  width: 14px;
  height: 2px;
  background: var(--gold);
  display: inline-block;
  transform: translateY(-4px);
}

h3.sub-head {
  font-family: var(--font-body);
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--accent);
  margin: 26px 0 12px;
}

p { margin: 0 0 14px; color: var(--ink); }
.muted { color: var(--ink-soft); }

/* ---------- Research / figure cards ---------- */
.figure-card {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--white);
  padding: 18px;
  margin: 14px 0 28px;
  max-width: 500px;
}
.figure-card img { border-radius: 2px; }
.figure-caption {
  font-size: .85rem;
  color: var(--ink-soft);
  margin-top: 10px;
  font-style: italic;
}

/* Timeline-style research list (signature element) */
.research-timeline {
  position: relative;
  padding-left: 24px;
  border-left: 2px solid var(--line);
}
.research-item { position: relative; margin-bottom: 36px; }
.research-item::before {
  content: '';
  position: absolute;
  left: -29px;
  top: 4px;
  width: 9px;
  height: 9px;
  border-radius: 50%;
  background: var(--gold);
  border: 2px solid var(--bg);
  box-shadow: 0 0 0 1px var(--gold);
}
.research-item h3 {
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 1.02rem;
  margin: 0 0 10px;
  color: var(--ink);
}

/* ---------- Publication list ---------- */
ol.pub-list { list-style: none; margin: 0; padding: 0; counter-reset: pub; }
ol.pub-list > li {
  counter-increment: pub;
  position: relative;
  padding: 14px 0 14px 38px;
  border-bottom: 1px solid var(--line);
  font-size: .96rem;
}
ol.pub-list > li:last-child { border-bottom: none; }
ol.pub-list > li::before {
  content: counter(pub);
  position: absolute;
  left: 0;
  top: 14px;
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--gold);
  width: 26px;
}
ol.pub-list .pub-title { font-style: italic; color: var(--ink); }
ol.pub-list .pub-venue { color: var(--ink-soft); font-size: .9rem; }
ol.pub-list .pdf-link {
  font-family: var(--font-mono);
  font-size: .72rem;
  letter-spacing: .03em;
  text-transform: uppercase;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 2px;
  padding: 2px 7px;
  margin-left: 8px;
  white-space: nowrap;
}
ol.pub-list .pdf-link:hover { background: var(--accent); color: var(--white); border-bottom: 1px solid var(--accent); }

/* generic lists used across pages */
ul.plain-list, ol.plain-list { padding-left: 22px; margin: 0 0 8px; }
ul.plain-list li, ol.plain-list li { margin-bottom: 9px; }

/* simple two-column key/value rows (education, jobs) */
.entry-row {
  display: flex;
  gap: 18px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}
.entry-row:last-child { border-bottom: none; }
.entry-date {
  font-family: var(--font-mono);
  font-size: .8rem;
  color: var(--gold);
  white-space: nowrap;
  flex-shrink: 0;
  width: 150px;
  padding-top: 2px;
}
.entry-body { flex: 1; }
.entry-title { font-weight: 600; }

/* tag-style group label (纵向/横向/European) */
.tag {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: .72rem;
  text-transform: uppercase;
  letter-spacing: .04em;
  color: var(--accent);
  background: var(--bg-panel);
  border-radius: 2px;
  padding: 2px 8px;
  margin-bottom: 14px;
}

footer.site-footer {
  margin-top: 60px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
  font-size: .78rem;
  color: var(--ink-soft);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 10px;
}

/* mobile nav toggle */
.mobile-nav-toggle { display: none; }

/* ---------- Responsive ---------- */
@media (max-width: 860px) {
  .layout { flex-direction: column; }
  .sidebar {
    width: 100%;
    height: auto;
    position: relative;
    padding: 24px 20px;
    flex-direction: row;
    align-items: center;
    flex-wrap: wrap;
  }
  .sidebar-photo { width: 84px; height: 110px; margin-right: 18px; margin-bottom: 0; }
  .sidebar-contact, .sidebar-links { display: none; }
  .sidebar-name { font-size: 1.25rem; }
  nav.sidebar-nav {
    width: 100%;
    border-top: 1px solid var(--line);
    margin-top: 18px;
    padding-top: 14px;
  }
  .sidebar-nav .menu-label { display: none; }
  nav.sidebar-nav ul { display: flex; gap: 4px; flex-wrap: wrap; list-style: none; padding: 0; margin: 0; }
  nav.sidebar-nav a { padding: 6px 10px; font-size: .88rem; }
  nav.sidebar-nav a.current { border-left: none; padding-left: 10px; background: var(--bg-panel); border-radius: 2px; }
  .content { padding: 32px 20px 60px; max-width: 100%; }
  .entry-row { flex-direction: column; gap: 4px; }
  .entry-date { width: auto; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  * { transition: none !important; }
}