/* ===========================================================
   Scientist Homepage Template — stylesheet
   Tokens → reset → layout → components → responsive
   =========================================================== */

/* ---------- 1. Tokens (light) ---------- */
:root {
  /* color */
  --bg: #fbfaf7;
  --bg-elevated: #ffffff;
  --bg-subtle: #f1efe9;
  --text: #1a1d23;
  --text-muted: #5a6068;
  --text-subtle: #6e7480;
  --accent: #1e4ba0;
  --accent-hover: #173a80;
  --border: #e3dfd6;
  --border-strong: #cdc7b9;
  --shadow: 0 1px 2px rgba(20, 22, 28, 0.04), 0 4px 12px rgba(20, 22, 28, 0.04);

  /* type */
  --font-sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-serif: "Newsreader", Georgia, "Times New Roman", serif;
  --fs-display: 2.25rem;
  --fs-h1: 1.625rem;
  --fs-h2: 1.25rem;
  --fs-body: 1.0625rem;
  --fs-meta: 0.9375rem;
  --fs-small: 0.8125rem;
  --fs-badge: 0.6875rem;

  /* spacing */
  --s-4: 4px;
  --s-8: 8px;
  --s-12: 12px;
  --s-16: 16px;
  --s-24: 24px;
  --s-32: 32px;
  --s-48: 48px;
  --s-64: 64px;
  --s-96: 96px;

  /* layout */
  --container: 820px;
  --nav-height: 56px;

  --radius-sm: 4px;
  --radius-md: 6px;
  --radius-lg: 8px;
  --radius-pill: 999px;

  --transition: 160ms ease;
}

/* ---------- Tokens (dark) ---------- */
[data-theme="dark"] {
  --bg: #0f1620;
  --bg-elevated: #161e2a;
  --bg-subtle: #1d2735;
  --text: #e8ecf2;
  --text-muted: #a7afbd;
  --text-subtle: #828b9c;
  --accent: #6ea3e8;
  --accent-hover: #8fbaf0;
  --border: #2a3444;
  --border-strong: #3a4658;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 4px 12px rgba(0, 0, 0, 0.25);
}

/* Auto dark when no manual toggle */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    --bg: #0f1620;
    --bg-elevated: #161e2a;
    --bg-subtle: #1d2735;
    --text: #e8ecf2;
    --text-muted: #a7afbd;
    --text-subtle: #828b9c;
    --accent: #6ea3e8;
    --accent-hover: #8fbaf0;
    --border: #2a3444;
    --border-strong: #3a4658;
  }
}

/* ---------- 2. Reset / base ---------- */
*, *::before, *::after { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--nav-height) + 16px);
}

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

img { max-width: 100%; display: block; }
ul, ol { padding: 0; margin: 0; list-style: none; }
p { margin: 0 0 var(--s-12); }
a { color: var(--accent); text-decoration: underline; text-underline-offset: 2px; transition: color var(--transition); }
a:hover { color: var(--accent-hover); }
strong { font-weight: 600; }
em { font-style: italic; }

button {
  font-family: inherit;
  font-size: inherit;
  cursor: pointer;
  border: 0;
  background: transparent;
  color: inherit;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Skip link */
.skip-link {
  position: absolute;
  left: var(--s-16);
  top: -100px;
  background: var(--accent);
  color: #fff;
  padding: var(--s-8) var(--s-12);
  border-radius: var(--radius-sm);
  text-decoration: none;
  z-index: 1000;
  transition: top 120ms ease;
}
.skip-link:focus { top: var(--s-12); color: #fff; }

/* ---------- 3. Layout: header / nav ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(180%) blur(10px);
  -webkit-backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
}

.nav {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--s-24);
  height: var(--nav-height);
  display: flex;
  align-items: center;
  gap: var(--s-16);
}

.nav-brand {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--text);
  text-decoration: none;
  letter-spacing: 0.02em;
}

.nav-links {
  display: flex;
  flex: 1;
  justify-content: center;
  gap: var(--s-24);
  overflow-x: auto;
  scrollbar-width: none;
}
.nav-links::-webkit-scrollbar { display: none; }

.nav-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: var(--fs-small);
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  padding: var(--s-12) var(--s-4);
  white-space: nowrap;
  transition: color var(--transition);
}
.nav-links a:hover, .nav-links a.is-active {
  color: var(--accent);
}

.theme-toggle {
  width: 36px;
  height: 36px;
  border-radius: var(--radius-md);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  transition: color var(--transition), background var(--transition);
}
.theme-toggle:hover { color: var(--accent); background: var(--bg-subtle); }
.theme-toggle .icon-sun { display: none; }
.theme-toggle .icon-moon { display: block; }
[data-theme="dark"] .theme-toggle .icon-sun { display: block; }
[data-theme="dark"] .theme-toggle .icon-moon { display: none; }

/* ---------- 4. Main / sections ---------- */
main {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 var(--s-24);
}

main > section {
  padding: var(--s-64) 0;
  border-bottom: none;
}
main > section + section { padding-top: 0; }

.section-heading {
  font-family: var(--font-serif);
  font-weight: 600;
  font-size: var(--fs-h1);
  color: var(--text);
  margin: 0 0 var(--s-24);
  padding-bottom: var(--s-8);
  border-bottom: 1px solid var(--border);
  letter-spacing: -0.01em;
}

.meta { color: var(--text-muted); font-size: var(--fs-meta); }

/* ---------- 5. Hero ---------- */
.hero {
  display: flex;
  align-items: flex-start;
  gap: var(--s-32);
  padding-top: var(--s-64);
  padding-bottom: var(--s-48);
  border-bottom: none;
}

.hero-photo {
  width: 180px;
  height: 180px;
  border-radius: var(--radius-lg);
  object-fit: cover;
  flex-shrink: 0;
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
}

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

.hero-name {
  font-family: var(--font-serif);
  font-size: var(--fs-display);
  font-weight: 600;
  margin: 0 0 var(--s-4);
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--text);
}

.hero-title { font-weight: 500; color: var(--text-muted); margin: 0 0 var(--s-4); }
.hero-affiliation { color: var(--text-muted); margin: 0 0 var(--s-16); }
.hero-bio { color: var(--text); margin: 0 0 var(--s-24); max-width: 60ch; }

.social-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-16);
  align-items: center;
}
.social-row a {
  display: inline-flex;
  width: 36px;
  height: 36px;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: color var(--transition), background var(--transition), transform var(--transition);
}
.social-row a:hover {
  color: var(--accent);
  background: var(--bg-subtle);
  transform: translateY(-1px);
}

/* ---------- 6. News ---------- */
.news-list { display: flex; flex-direction: column; gap: var(--s-12); }
.news-list li { display: flex; gap: var(--s-16); align-items: baseline; }
.news-date {
  flex-shrink: 0;
  width: 96px;
  color: var(--text-muted);
  font-weight: 500;
  font-size: var(--fs-meta);
  font-variant-numeric: tabular-nums;
}
.news-more { margin-top: var(--s-16); font-size: var(--fs-meta); }

/* ---------- 7. Publications ---------- */
.pub-filter {
  display: flex;
  gap: var(--s-8);
  flex-wrap: wrap;
  margin: var(--s-16) 0 var(--s-32);
}
.pub-filter-btn {
  padding: var(--s-4) var(--s-12);
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  font-size: var(--fs-small);
  font-weight: 500;
  color: var(--text-muted);
  background: var(--bg-elevated);
  transition: all var(--transition);
}
.pub-filter-btn:hover { border-color: var(--border-strong); color: var(--text); }
.pub-filter-btn.is-active {
  background: var(--accent);
  color: #fff;
  border-color: var(--accent);
}

.pub-year {
  font-family: var(--font-serif);
  font-size: var(--fs-h2);
  font-weight: 600;
  color: var(--text-muted);
  margin: var(--s-32) 0 var(--s-16);
  padding-bottom: var(--s-4);
  border-bottom: 1px dashed var(--border);
}
.pub-year:first-of-type { margin-top: var(--s-16); }

.pub {
  display: block;
  padding: var(--s-16) 0;
  border-bottom: 1px solid var(--border);
}
.pub:last-child { border-bottom: none; }

/* Critical: must beat .pub specificity (0,0,1,0) so [hidden] year-filter actually hides */
.pub[hidden], .pub-year[hidden] { display: none !important; }

/* Paper title is a link to DOI — keep typography, accent on hover */
.pub-title a {
  color: inherit;
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--transition), border-color var(--transition);
}
.pub-title a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

.pub-thumb {
  display: block;
  max-width: 100%;
  height: auto;
  margin-bottom: var(--s-12);
  border-radius: var(--radius-md);
  border: 1px solid var(--border);
  background: var(--bg-subtle);
}

.pub-body { min-width: 0; }

.pub-badge-flag {
  display: inline-block;
  font-size: var(--fs-badge);
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  padding: 2px var(--s-8);
  border-radius: var(--radius-pill);
  margin-bottom: var(--s-8);
}

.pub-title {
  font-family: var(--font-serif);
  font-size: var(--fs-h2);
  font-weight: 600;
  color: var(--text);
  margin: 0 0 var(--s-4);
  line-height: 1.3;
}
.pub-authors { font-size: var(--fs-meta); color: var(--text-muted); margin: 0 0 var(--s-4); }
.pub-authors strong { color: var(--text); font-weight: 600; }
.pub-venue { font-size: var(--fs-meta); color: var(--text-muted); margin: 0; }

/* ---------- 8. Badges ---------- */
.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--s-8);
  margin-top: var(--s-12);
}

.badge {
  display: inline-flex;
  align-items: center;
  height: 22px;
  padding: 0 10px;
  border-radius: var(--radius-pill);
  font-size: var(--fs-badge);
  font-weight: 600;
  letter-spacing: 0.02em;
  text-decoration: none;
  color: #fff;
  transition: filter var(--transition), transform var(--transition);
}
.badge:hover { filter: brightness(1.1); transform: translateY(-1px); color: #fff; }

.badge-arxiv   { background: #b31b1b; }
.badge-pdf     { background: #5a6068; }
.badge-code    { background: #24292f; }
.badge-hf      { background: #FFD21E; color: #1a1d23; }
.badge-hf:hover { color: #1a1d23; }
.badge-project { background: #1e4ba0; }
.badge-bibtex  { background: #7a6a3f; }
.badge-slides  { background: #0d8f6c; }
.badge-video   { background: #a13a8e; }

/* ---------- 9. Experience timeline ---------- */
.timeline {
  position: relative;
  padding-left: var(--s-24);
  border-left: 1px solid var(--border);
  margin-left: var(--s-8);
}
.timeline-item {
  position: relative;
  padding-bottom: var(--s-24);
}
.timeline-item:last-child { padding-bottom: 0; }
.timeline-item::before {
  content: "";
  position: absolute;
  left: calc(var(--s-24) * -1 - 5px);
  top: 8px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--accent);
  border: 2px solid var(--bg);
}
.timeline-role {
  font-family: var(--font-sans);
  font-size: var(--fs-body);
  font-weight: 600;
  color: var(--text);
  margin: 0 0 var(--s-4);
}
.timeline-org { font-size: var(--fs-meta); color: var(--text-muted); margin: 0 0 var(--s-4); }
.timeline-loc { color: var(--text-subtle); }
.timeline-date { font-size: var(--fs-small); color: var(--text-subtle); font-weight: 500; margin: 0; font-variant-numeric: tabular-nums; }

/* ---------- 10. Honors / Services / Contact ---------- */
.honor-list { display: flex; flex-direction: column; gap: var(--s-8); }
.honor-list li { display: flex; gap: var(--s-16); align-items: baseline; }
.honor-year {
  flex-shrink: 0;
  width: 56px;
  color: var(--text-muted);
  font-weight: 500;
  font-size: var(--fs-meta);
  font-variant-numeric: tabular-nums;
}

.services-sub {
  font-family: var(--font-serif);
  font-size: var(--fs-h2);
  font-weight: 600;
  color: var(--text);
  margin: var(--s-24) 0 var(--s-12);
}

.bullet-list { display: flex; flex-direction: column; gap: var(--s-4); padding-left: var(--s-16); list-style: disc; color: var(--text); }
.bullet-list li { font-size: var(--fs-body); }
.bullet-list li::marker { color: var(--text-subtle); }

.contact-list { display: flex; flex-direction: column; gap: var(--s-12); }
.contact-list li { display: flex; gap: var(--s-16); align-items: baseline; flex-wrap: wrap; }
.contact-label {
  flex-shrink: 0;
  width: 92px;
  color: var(--text-muted);
  font-weight: 500;
  font-size: var(--fs-meta);
}

/* ---------- 11. Footer ---------- */
.site-footer {
  max-width: var(--container);
  margin: var(--s-32) auto 0;
  padding: var(--s-48) var(--s-24);
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: var(--fs-small);
  color: var(--text-subtle);
}
.site-footer p { margin: 0 0 var(--s-8); }
.site-footer a { color: var(--text-muted); }
.site-footer a:hover { color: var(--accent); }
#visitor-counter {
  margin: var(--s-16) auto;
  min-height: 24px;
  display: flex;
  justify-content: center;
}
.counter-placeholder {
  font-family: ui-monospace, "SF Mono", Menlo, monospace;
  font-size: var(--fs-small);
  color: var(--text-subtle);
  padding: var(--s-4) var(--s-12);
  border: 1px dashed var(--border);
  border-radius: var(--radius-sm);
}

/* ---------- 12. Responsive ---------- */
@media (max-width: 1024px) {
  .hero-photo { width: 140px; height: 140px; }
  .hero-name { font-size: 2rem; }
}

@media (max-width: 640px) {
  :root { --fs-body: 1rem; --fs-display: 1.875rem; --fs-h1: 1.4rem; }

  main, .nav, .site-footer { padding-left: var(--s-16); padding-right: var(--s-16); }
  main > section { padding: var(--s-48) 0; }

  .nav { gap: var(--s-8); }
  .nav-links { gap: var(--s-16); justify-content: flex-start; }

  .hero {
    flex-direction: column;
    align-items: flex-start;
    gap: var(--s-16);
    padding-top: var(--s-32);
    padding-bottom: var(--s-32);
  }
  .hero-photo { width: 120px; height: 120px; }
  .social-row { gap: var(--s-12); }
  .social-row a { width: 40px; height: 40px; }

  .news-list li { flex-direction: column; gap: var(--s-4); }
  .news-date { width: auto; }

  /* .pub already display:block above; nothing to override at mobile */

  .honor-list li { flex-direction: column; gap: var(--s-4); }
  .honor-year { width: auto; }

  .contact-list li { flex-direction: column; gap: var(--s-4); }
  .contact-label { width: auto; }
}

/* ---------- 13. Print ---------- */
@media print {
  .site-header, .theme-toggle, .pub-filter, .news-more, .skip-link { display: none !important; }
  body { background: #fff; color: #000; }
  a { color: #000; text-decoration: underline; }
  main { max-width: 100%; }
}

/* =========================================================================
   Two-column sticky sidebar redesign
   Overrides earlier single-column hero layout. Main holds .shell which
   is a grid of sticky sidebar + main content column.
   ========================================================================= */

main {
  max-width: 1180px;
  padding: 0 24px 64px;
}

main > .shell {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 56px;
  align-items: start;
  padding-top: var(--s-32);
}

.sidebar {
  position: sticky;
  top: calc(var(--nav-height) + 24px);
  align-self: start;
}

.sidebar-photo {
  display: block;
  width: 200px;
  height: 200px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border);
  margin: 0 0 var(--s-16);
}

.sidebar-name {
  font-family: var(--font-sans);
  font-size: 1.5rem;
  font-weight: 600;
  margin: 0 0 var(--s-4);
  color: var(--text);
  line-height: 1.2;
}

.sidebar-affiliation {
  font-size: var(--fs-meta);
  color: var(--text-muted);
  margin: 0 0 var(--s-4);
}

.sidebar-tagline {
  font-size: var(--fs-small);
  color: var(--text-subtle);
  margin: 0 0 var(--s-16);
}

.sidebar-contact {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: var(--s-8);
}

.sidebar-contact li {
  display: flex;
  align-items: center;
  gap: var(--s-8);
  font-size: var(--fs-meta);
  color: var(--text-muted);
}

.sidebar-contact svg { flex: 0 0 auto; color: var(--text-muted); }

.sidebar-contact a {
  color: var(--text);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: color var(--transition), border-color var(--transition);
}

.sidebar-contact a:hover {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* Main column: re-establish section spacing (rules tied to `main > section` no longer match) */
.main-col > section {
  padding: var(--s-48) 0 0;
}
.main-col > section:first-child { padding-top: 0; }

/* Section heading: underline like academic templates, sans-serif (override serif) */
.main-col .section-heading {
  font-family: var(--font-sans);
  font-size: 1.625rem;
  font-weight: 600;
  border-bottom: 1px solid var(--border);
  padding-bottom: var(--s-8);
  margin: 0 0 var(--s-24);
  color: var(--text);
}

/* Section subheading (h3) inside a section */
.main-col .section-subheading {
  font-family: var(--font-sans);
  font-size: 1.125rem;
  font-weight: 600;
  margin: var(--s-32) 0 var(--s-12);
  color: var(--text);
}

/* Research-interests bullet list */
.research-list {
  list-style: disc;
  padding-left: 1.25rem;
  margin: 0 0 var(--s-16);
}

.research-list li {
  margin-bottom: var(--s-12);
  line-height: 1.65;
}

.research-list li strong {
  color: var(--text);
}

/* Mobile collapse: stack sidebar above content, lose stickiness */
@media (max-width: 900px) {
  main { padding: 0 16px 48px; }

  main > .shell {
    grid-template-columns: 1fr;
    gap: var(--s-32);
    padding-top: var(--s-24);
  }

  .sidebar {
    position: static;
    text-align: left;
  }

  .sidebar-photo {
    width: 160px;
    height: 160px;
  }
}