:root {
  --bg: #ffffff;
  --surface: #f7f8fa;
  --text: #1c2024;
  --muted: #5b6470;
  --accent: #2b4c7e;
  --accent-soft: #e8eef6;
  --border: #e2e5ea;
  --badge-review-bg: #fff4e5;
  --badge-review-text: #8a5a00;
  --maxw: 760px;
}

html[data-theme="dark"] {
  --bg: #14171a;
  --surface: #1c2024;
  --text: #e6e8eb;
  --muted: #9aa3ad;
  --accent: #8fb2e0;
  --accent-soft: #21303f;
  --border: #2a2f35;
  --badge-review-bg: #3a2e16;
  --badge-review-text: #e6b873;
}

@media (prefers-color-scheme: dark) {
  html:not([data-theme="light"]) {
    --bg: #14171a;
    --surface: #1c2024;
    --text: #e6e8eb;
    --muted: #9aa3ad;
    --accent: #8fb2e0;
    --accent-soft: #21303f;
    --border: #2a2f35;
    --badge-review-bg: #3a2e16;
    --badge-review-text: #e6b873;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  font-size: 17px;
}

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

/* Header / nav */
.site-header {
  position: sticky;
  top: 0;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--border);
  z-index: 10;
}
.nav {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0.6rem 1.2rem;
  display: flex;
  align-items: center;
  gap: 1rem;
}
.nav-brand { font-weight: 700; color: var(--text); }
.nav-links {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  gap: 1rem;
  margin: 0;
  padding: 0;
  flex: 1;
}
.nav-links a { color: var(--muted); font-size: 0.92rem; }
.nav-links a:hover { color: var(--accent); text-decoration: none; }
.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.language-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.15rem;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.15rem;
  font-size: 0.78rem;
  line-height: 1;
}
.language-toggle a,
.language-toggle span {
  display: inline-flex;
  align-items: center;
  min-height: 1.45rem;
  padding: 0 0.35rem;
}
.language-toggle a { color: var(--muted); }
.language-toggle a:hover { color: var(--accent); text-decoration: none; }
.language-toggle span {
  background: var(--accent-soft);
  color: var(--accent);
  border-radius: 6px;
  font-weight: 700;
}
.theme-toggle {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.25rem 0.5rem;
  cursor: pointer;
  font-size: 1rem;
  line-height: 1;
}

/* Main layout */
main {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1.5rem 1.2rem 3rem;
}
section { padding: 1.4rem 0; border-top: 1px solid var(--border); }
section:first-of-type { border-top: none; }
h1 { font-size: 2.1rem; margin: 0 0 0.2rem; }
h2 { font-size: 1.25rem; color: var(--accent); margin: 0 0 0.8rem; }

/* Hero */
.hero { padding-top: 1.6rem; }
.hero-role { color: var(--muted); font-size: 1.05rem; margin: 0 0 0.9rem; }
.hero-bio { margin: 0 0 1rem; }
.hero-links, .nav-links { list-style: none; }
.hero-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 1rem;
  margin: 0;
  padding: 0;
}
.hero-links a { font-weight: 600; }

/* Lists */
.research-list { padding-left: 1.1rem; margin: 0; }
.research-list li { margin-bottom: 0.5rem; }

.news-list, .teach-list { list-style: none; padding: 0; margin: 0; }
.news-list li, .teach-list li { margin-bottom: 0.5rem; }
.news-date, .teach-date {
  display: inline-block;
  min-width: 5.2rem;
  font-weight: 600;
  color: var(--muted);
}

/* Publications */
.pub-note { color: var(--muted); margin: 0 0 0.8rem; font-size: 0.9rem; }
.pub-list { list-style: none; padding-left: 0; margin: 0; }
.pub-list li { margin-bottom: 1rem; }
.pub-title { display: block; font-weight: 600; }
.pub-venue {
  display: inline-block;
  margin: 0.2rem 0;
  padding: 0.05rem 0.5rem;
  background: var(--accent-soft);
  color: var(--accent);
  border-radius: 6px;
  font-size: 0.82rem;
  font-weight: 600;
}
.pub-venue.badge-review {
  background: var(--badge-review-bg);
  color: var(--badge-review-text);
}
.pub-links { display: block; font-size: 0.9rem; color: var(--muted); }

/* Footer */
.site-footer {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 1.4rem 1.2rem;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.88rem;
}

/* Responsive */
@media (max-width: 720px) {
  body { font-size: 16px; }
  .nav { flex-wrap: wrap; }
  .nav-links { order: 3; width: 100%; }
  .nav-actions { margin-left: auto; }
  h1 { font-size: 1.8rem; }
  .news-date, .teach-date { display: block; min-width: 0; }
}

/* News: scrollable box with a faded, blurred bottom edge */
.news-box {
  position: relative;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 0.5rem 0.95rem;
}
.news-box .news-list {
  max-height: 150px;
  overflow-y: auto;
  padding-right: 0.6rem;
  scrollbar-width: thin;
}
.news-box .news-list li:last-child { margin-bottom: 0.2rem; }
.news-box::after {
  content: "";
  position: absolute;
  left: 1px;
  right: 1px;
  bottom: 1px;
  height: 44px;
  border-radius: 0 0 10px 10px;
  background: linear-gradient(to bottom, transparent, var(--surface));
  backdrop-filter: blur(1.5px);
  -webkit-mask-image: linear-gradient(to bottom, transparent, #000 75%);
  mask-image: linear-gradient(to bottom, transparent, #000 75%);
  pointer-events: none;
}

/* Hero avatar */
.hero-head {
  display: flex;
  align-items: center;
  gap: 1.2rem;
  margin-bottom: 0.9rem;
}
.hero-head h1 { margin: 0 0 0.2rem; }
.hero-head .hero-role { margin: 0; }
.avatar {
  width: 150px;
  height: 150px;
  border-radius: 50%;
  object-fit: cover;
  object-position: center;
  border: 3px solid var(--border);
  flex-shrink: 0;
}
@media (max-width: 720px) {
  .hero-head { flex-direction: column; align-items: flex-start; gap: 0.8rem; }
  .avatar { width: 120px; height: 120px; }
}

/* Teaching: fixed-width date column so course titles align */
.teach-date { width: 7rem; min-width: 7rem; }
@media (max-width: 720px) {
  .teach-date { width: auto; min-width: 0; }
}

/* Publication authors */
.pub-authors { display: block; font-size: 0.9rem; color: var(--muted); margin: 0.1rem 0; }
.pub-authors strong { color: var(--text); }

/* Nested research sub-bullets */
.research-list > li > ul { margin: 0.4rem 0 0; padding-left: 1.1rem; }
.research-list > li > ul > li { margin-bottom: 0.4rem; }