:root {
  --text: #1c1c1c;
  --muted: #6b6b6b;
  --accent: #2f5d50;
  --accent-hover: #234739;
  --line: #e6e6e6;
  --bg: #ffffff;
  --bg-soft: #f7f6f3;
  --maxw: 880px;
  --serif: "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, "Times New Roman", serif;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--text);
  background: var(--bg);
  line-height: 1.65;
  font-size: 18px;
}

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

h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.2;
  color: var(--text);
}

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

/* ---------- Layout ---------- */
.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

section { padding: 56px 0; }
section + section { border-top: 1px solid var(--line); }

/* ---------- Nav ---------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.site-nav .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 16px;
  padding-bottom: 16px;
}
.site-nav .brand {
  font-family: var(--serif);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text);
}
.site-nav .brand:hover { text-decoration: none; }
.site-nav ul {
  list-style: none;
  display: flex;
  gap: 28px;
  margin: 0;
  padding: 0;
}
.site-nav a.navlink {
  color: var(--muted);
  font-size: 0.95rem;
  letter-spacing: 0.02em;
}
.site-nav a.navlink:hover,
.site-nav a.navlink.active {
  color: var(--text);
  text-decoration: none;
}
.site-nav a.navlink.active { border-bottom: 2px solid var(--accent); padding-bottom: 4px; }

/* ---------- Research sub-nav ---------- */
.subnav {
  position: sticky;
  top: 62px;
  z-index: 40;
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: saturate(180%) blur(8px);
  border-bottom: 1px solid var(--line);
}
.subnav .container {
  display: flex;
  gap: 28px;
  padding-top: 13px;
  padding-bottom: 13px;
}
.subnav-link {
  font-size: 0.92rem;
  color: var(--muted);
  letter-spacing: 0.02em;
  padding-bottom: 4px;
  border-bottom: 2px solid transparent;
}
.subnav-link:hover { color: var(--text); text-decoration: none; }
.subnav-link.active {
  color: var(--text);
  border-bottom-color: var(--accent);
}
main section[id^="sec-"] { scroll-margin-top: 116px; }

@media (max-width: 680px) {
  .subnav { top: 0; }
  .subnav .container { gap: 16px; overflow-x: auto; white-space: nowrap; }
  main section[id^="sec-"] { scroll-margin-top: 60px; }
}

/* ---------- Hero banner ---------- */
.hero-banner {
  position: relative;
  margin: 0;
  width: 100%;
  max-height: 460px;
  overflow: hidden;
}
.hero-banner img {
  width: 100%;
  height: 100%;
  max-height: 460px;
  object-fit: cover;
  object-position: center 60%;
}
.hero-credit {
  position: absolute;
  right: 10px;
  bottom: 8px;
  margin: 0;
  font-size: 0.72rem;
  color: #fff;
  background: rgba(0, 0, 0, 0.35);
  padding: 3px 8px;
  border-radius: 3px;
  letter-spacing: 0.02em;
}

/* ---------- Hero / intro ---------- */
.intro {
  display: grid;
  grid-template-columns: 220px 1fr;
  gap: 44px;
  align-items: start;
  padding-top: 56px;
}
.intro .photo img {
  width: 220px;
  height: 220px;
  object-fit: cover;
  border-radius: 50%;
  box-shadow: 0 4px 18px rgba(0,0,0,0.10);
}
.intro h1 {
  margin: 0 0 6px;
  font-size: 2.4rem;
}
.intro .role {
  color: var(--muted);
  font-size: 1.05rem;
  margin: 0 0 20px;
}
.intro .bio p { margin: 0 0 16px; }

.social {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 22px;
}
.social a {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  font-size: 0.92rem;
  color: var(--text);
  border: 1px solid var(--line);
  padding: 7px 14px;
  border-radius: 999px;
  background: var(--bg-soft);
}
.social a:hover { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.social svg { width: 16px; height: 16px; fill: currentColor; }

/* ---------- Education ---------- */
.section-title {
  font-size: 1.5rem;
  margin: 0 0 24px;
}
.edu-list { list-style: none; margin: 0; padding: 0; }
.edu-list li {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  padding: 12px 0;
  border-bottom: 1px solid var(--line);
}
.edu-list li:last-child { border-bottom: 0; }
.edu-list .deg { font-weight: 600; }
.edu-list .inst { color: var(--muted); }
.edu-list .yr { color: var(--muted); white-space: nowrap; font-variant-numeric: tabular-nums; }

/* ---------- Research / publications ---------- */
.research-sub { margin-bottom: 12px; }
.research-sub h2 {
  font-size: 1.4rem;
  margin: 0 0 4px;
}
.research-sub .sub-note {
  color: var(--muted);
  font-size: 0.95rem;
  margin: 0 0 18px;
}

.pub-list { list-style: none; margin: 0; padding: 0; }
.pub {
  padding: 22px 0;
  border-bottom: 1px solid var(--line);
}
.pub:last-child { border-bottom: 0; }
.pub .pub-title {
  font-family: var(--serif);
  font-size: 1.12rem;
  font-weight: 600;
  margin: 0 0 6px;
}
.pub .pub-authors { font-size: 0.97rem; margin: 0 0 4px; color: #333; }
.pub .pub-authors .me { font-weight: 700; color: var(--text); }
.pub .pub-meta {
  font-size: 0.95rem;
  color: var(--muted);
  margin: 0 0 10px;
}
.pub .pub-meta .venue { font-style: italic; }
.pub .pub-meta .status {
  display: inline-block;
  background: var(--bg-soft);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 1px 8px;
  font-style: normal;
  font-size: 0.85rem;
  color: #4a4a4a;
}
.pub-links {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 10px;
  margin-top: 8px;
}
.pub-links a {
  font-size: 0.85rem;
  border: 1px solid var(--line);
  padding: 3px 11px;
  border-radius: 999px;
  color: var(--accent);
}
.pub-links a:hover { background: var(--accent); color: #fff; text-decoration: none; border-color: var(--accent); }

.pub-media {
  margin-top: 9px;
  font-size: 0.84rem;
  color: var(--muted);
  line-height: 1.7;
}
.pub-media .media-label {
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-size: 0.74rem;
  color: #9a9a9a;
  margin-right: 4px;
}
.pub-media a {
  color: var(--muted);
  text-decoration: underline;
  text-decoration-color: var(--line);
  text-underline-offset: 2px;
}
.pub-media a:hover { color: var(--accent); text-decoration-color: var(--accent); }
.pub-media .sep { color: #c4c4c4; }

.abstract-toggle {
  background: none;
  border: 0;
  padding: 0;
  margin-top: 10px;
  font: inherit;
  font-size: 0.85rem;
  color: var(--muted);
  cursor: pointer;
}
.abstract-toggle:hover { color: var(--accent); }
.pub-abstract {
  display: none;
  margin-top: 10px;
  padding: 14px 16px;
  background: var(--bg-soft);
  border-radius: 6px;
  font-size: 0.95rem;
  color: #333;
}
.pub-abstract.open { display: block; }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--line);
  padding: 32px 0;
  color: var(--muted);
  font-size: 0.88rem;
  text-align: center;
}

/* ---------- Responsive ---------- */
@media (max-width: 680px) {
  body { font-size: 17px; }
  .site-nav .container { flex-direction: column; gap: 12px; align-items: flex-start; }
  .site-nav ul { gap: 18px; }
  .intro {
    grid-template-columns: 1fr;
    gap: 24px;
    text-align: center;
    padding-top: 40px;
  }
  .intro .photo img { margin: 0 auto; width: 170px; height: 170px; }
  .intro h1 { font-size: 2rem; }
  .social { justify-content: center; }
  .edu-list li { flex-direction: column; gap: 2px; }
}