:root {
  --bg: #faf9f6;
  --header-bg-rgb: 250, 249, 246;
  --ink: #22201d;
  --ink-soft: #5b564e;
  --rule: #e3ddd2;
  --accent: #6b3a2e;
  --link: #6b3a2e;
  --max-width: 840px;
  --font-serif: "Source Serif 4", Georgia, serif;
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

/* Follows the OS/browser preference unless overridden by the toggle below. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #171513;
    --header-bg-rgb: 23, 21, 19;
    --ink: #ece7e0;
    --ink-soft: #a39b8e;
    --rule: #37312a;
    --link: #e2a189;
  }
}

/* Manual override via the theme-toggle button (wins in both directions). */
:root[data-theme="dark"] {
  --bg: #171513;
  --header-bg-rgb: 23, 21, 19;
  --ink: #ece7e0;
  --ink-soft: #a39b8e;
  --rule: #37312a;
  --link: #e2a189;
}

* { box-sizing: border-box; }

/* Smooths the light/dark toggle instead of an instant color snap. */
*, *::before, *::after {
  transition: background-color 0.25s ease, color 0.25s ease, border-color 0.25s ease;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { transition: none; }
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 76px; /* keeps anchor targets from hiding behind the sticky header */
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.65;
}

h1, h2 {
  font-family: var(--font-serif);
  font-weight: 600;
  color: var(--ink);
  margin: 0 0 0.4em;
}

h1 { font-size: 2rem; }

h2 {
  font-size: 1.4rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--rule);
  margin-bottom: 1.2rem;
}

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

/* ---------- header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  background: rgba(var(--header-bg-rgb), 0.92);
  backdrop-filter: blur(6px);
  border-bottom: 1px solid var(--rule);
  z-index: 10;
}

.nav {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0.9rem 1.5rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem 1.2rem;
}

.nav-name {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--ink);
}
.nav-name:hover { text-decoration: none; color: var(--link); }

.nav-links {
  display: flex;
  align-items: center;
  gap: 1.2rem;
  flex-wrap: wrap;
}

@media (max-width: 420px) {
  .nav-links { gap: 0.7rem; }
}

.nav-links a {
  color: var(--ink-soft);
  font-size: 0.95rem;
}
.nav-links a:hover { color: var(--link); }

.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  background: none;
  border: none;
  padding: 0.25rem;
  margin: 0;
  color: var(--ink-soft);
  cursor: pointer;
}
.theme-toggle:hover { color: var(--link); }
.theme-toggle svg { width: 18px; height: 18px; }

.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: block; }

:root[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
:root[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .icon-sun { display: block; }
  :root:not([data-theme="light"]) .theme-toggle .icon-moon { display: none; }
}

/* ---------- layout ---------- */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.section {
  padding: 3rem 0;
  border-bottom: 1px solid var(--rule);
}
.section:last-child { border-bottom: none; }

.section-note {
  color: var(--ink-soft);
  font-size: 0.92rem;
}

/* ---------- sidebar + content layout ---------- */
.layout {
  display: flex;
  align-items: flex-start;
  gap: 2.5rem;
}

.sidebar {
  flex: none;
  width: 110px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.9rem;
  position: sticky;
  top: 5.5rem;
  padding-top: 3rem;
}

.content {
  flex: 1;
  min-width: 0;
}

.avatar {
  flex: none;
  width: 84px;
  height: 84px;
  border-radius: 50%;
  overflow: hidden;
  position: relative;
}

.avatar img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}

.avatar-fallback {
  display: none;
  width: 100%;
  height: 100%;
  background: var(--accent);
  color: #fff;
  font-family: var(--font-serif);
  font-size: 1.6rem;
  align-items: center;
  justify-content: center;
}

.title-line {
  color: var(--ink-soft);
  font-size: 1.02rem;
  margin: 0.2rem 0 1rem;
}

.bio-body { margin: 0 0 1.2rem; }

.last-updated {
  color: var(--ink-soft);
  font-size: 0.85rem;
  margin: 0;
}

.links-row {
  display: flex;
  flex-direction: row;
  justify-content: center;
  gap: 0.9rem;
}

.links-row a {
  color: var(--ink-soft);
  display: flex;
}
.links-row a:hover { color: var(--link); }

.links-row svg {
  width: 20px;
  height: 20px;
}

@media (max-width: 680px) {
  .layout { flex-direction: column; align-items: center; }
  .sidebar { position: static; padding-top: 0; }
  .content { width: 100%; }
}

/* ---------- education ---------- */
.education-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.education-item {
  padding: 0.6rem 0;
  border-bottom: 1px dashed var(--rule);
}
.education-item:last-child { border-bottom: none; }

.education-degree {
  display: block;
  font-family: var(--font-serif);
  font-weight: 600;
  margin-bottom: 0.15rem;
}

.education-meta {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 0.2rem 0.6rem;
}

.education-school { color: var(--ink-soft); }

.education-year {
  flex: none;
  color: var(--ink-soft);
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
}

/* ---------- news ---------- */
.news-list {
  list-style: none;
  margin: 0;
  padding: 0;
}

.news-item {
  display: flex;
  gap: 1.2rem;
  padding: 0.7rem 0;
  border-bottom: 1px dashed var(--rule);
}
.news-item:last-child { border-bottom: none; }

.news-date {
  flex: none;
  width: 90px;
  color: var(--ink-soft);
  font-size: 0.88rem;
  font-variant-numeric: tabular-nums;
  padding-top: 0.15rem;
}

.news-text { flex: 1; }

/* ---------- papers ---------- */
.paper-list {
  list-style: none;
  margin: 0;
  padding: 0;
  counter-reset: paper;
}

.paper-item {
  counter-increment: paper;
  padding: 1rem 0 1rem 2rem;
  position: relative;
  border-bottom: 1px dashed var(--rule);
}
.paper-item:last-child { border-bottom: none; }

.paper-item::before {
  content: counter(paper) ".";
  position: absolute;
  left: 0;
  color: var(--ink-soft);
  font-family: var(--font-serif);
}

.paper-title {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 1.05rem;
  display: block;
  margin-bottom: 0.25rem;
}

.paper-authors {
  color: var(--ink-soft);
  font-size: 0.94rem;
  margin-bottom: 0.15rem;
}
.paper-authors .me { color: var(--ink); font-weight: 600; }

.equal-contrib-note {
  font-size: 0.82rem;
  color: var(--ink-soft);
  margin-bottom: 0.3rem;
}

.paper-venue {
  font-size: 0.9rem;
  font-style: italic;
  color: var(--ink-soft);
  margin-bottom: 0.4rem;
}

.paper-links { display: flex; gap: 0.9rem; font-size: 0.88rem; }

/* ---------- footer ---------- */
.site-footer {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 2rem 1.5rem 3rem;
  color: var(--ink-soft);
  font-size: 0.85rem;
}