/* =========================================================
   Fonts — self-hosted, variable (each file spans the full
   weight axis + a matching italic):
     Source Serif 4  → headings
     Archivo         → body / UI
   ========================================================= */
@font-face {
  font-family: "Source Serif 4 Variable";
  font-style: normal;
  font-weight: 200 900;
  font-display: swap;
  src: url("../fonts/source-serif-4-latin-wght-normal.woff2") format("woff2");
}
@font-face {
  font-family: "Source Serif 4 Variable";
  font-style: italic;
  font-weight: 200 900;
  font-display: swap;
  src: url("../fonts/source-serif-4-latin-wght-italic.woff2") format("woff2");
}
@font-face {
  font-family: "Archivo Variable";
  font-style: normal;
  font-weight: 100 900;
  font-display: swap;
  src: url("../fonts/archivo-latin-wght-normal.woff2") format("woff2");
}
@font-face {
  font-family: "Archivo Variable";
  font-style: italic;
  font-weight: 100 900;
  font-display: swap;
  src: url("../fonts/archivo-latin-wght-italic.woff2") format("woff2");
}

/* =========================================================
   Design tokens
   ========================================================= */
:root {
  --max-width: 760px;
  --accent: #1a5fb4;           /* overridden from _config.yml via head.html */
  --fg: #1b1d20;
  --fg-muted: #5b6470;
  --bg: #ffffff;
  --bg-soft: #f5f6f8;
  --border: #e7e9ed;
  --radius: 12px;
  --nav-h: 60px;
  --font-serif: "Source Serif 4 Variable", Charter, "Bitstream Charter",
    "Sitka Text", Cambria, Georgia, "Times New Roman", serif;
  --font-sans: "Archivo Variable", "Helvetica Neue", Helvetica, Arial, sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --fg: #e6e8ea;
    --fg-muted: #9aa4b0;
    --bg: #0f1216;
    --bg-soft: #171b21;
    --border: #262b32;
  }
}

/* =========================================================
   Base
   ========================================================= */
*, *::before, *::after { box-sizing: border-box; }

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 17px;
  line-height: 1.65;
  letter-spacing: 0.02em;   /* open up Archivo, which is tight by default */
  color: var(--fg);
  background: var(--bg);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

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

h1, h2, h3 { font-family: var(--font-serif); line-height: 1.25; font-weight: 650; letter-spacing: normal; }

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 0.9em;
  background: var(--bg-soft);
  border: 1px solid var(--border);
  border-radius: 5px;
  padding: 1px 5px;
}

.empty { color: var(--fg-muted); }

/* Accessibility: skip link */
.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  background: var(--accent);
  color: #fff;
  padding: 8px 14px;
  border-radius: 0 0 var(--radius) 0;
}
.skip-link:focus { left: 0; }

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

/* =========================================================
   Navigation
   ========================================================= */
.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--bg);
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: saturate(180%) blur(10px);
  border-bottom: 1px solid var(--border);
  font-family: var(--font-serif);   /* match the serif name + section headings */
  letter-spacing: normal;
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand {
  font-weight: 700;
  color: var(--fg);
  white-space: nowrap;
}
.brand:hover { color: var(--accent); text-decoration: none; }

.nav-links {
  display: flex;
  gap: 18px;
  overflow-x: auto;
  scrollbar-width: none;
  -ms-overflow-style: none;
}
.nav-links::-webkit-scrollbar { display: none; }
.nav-links a {
  color: var(--fg-muted);
  font-size: 15px;
  white-space: nowrap;
  padding: 4px 0;
  border-bottom: 2px solid transparent;
}
.nav-links a:hover { color: var(--fg); text-decoration: none; }
.nav-links a.active { color: var(--accent); border-bottom-color: var(--accent); }

/* =========================================================
   Layout
   ========================================================= */
main {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}
.section {
  padding: 48px 0;
  border-top: 1px solid var(--border);
  scroll-margin-top: calc(var(--nav-h) + 10px);
}
.section:first-of-type { border-top: none; }
.section > h2 {
  font-size: 19px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--fg-muted);
  margin: 0 0 20px;
}
.section > h2::first-letter {
  font-size: 1.4em;   /* enlarged initial letter, e.g. the "N" in NEWS */
}

/* =========================================================
   About / hero
   ========================================================= */
.about { padding-top: 44px; }
.about-grid {
  display: grid;
  grid-template-columns: auto 1fr;
  grid-template-areas:
    "photo header"
    "bio   bio";
  column-gap: 28px;
  row-gap: 18px;
  align-items: start;     /* photo top-aligns with the first three lines */
}
.avatar-fig { grid-area: photo; margin: 0; }
.avatar {
  display: block;
  width: 132px;
  height: 132px;
  border-radius: var(--radius);
  object-fit: cover;
  border: 1px solid var(--border);
  background: var(--bg-soft);
}
.photo-caption {
  margin-top: 8px;
  max-width: 132px;
  font-size: 13px;
  line-height: 1.4;
  color: var(--fg-muted);
  text-align: center;
}
.about-header { grid-area: header; min-width: 0; }
.name { font-size: 30px; font-weight: 700; margin: 0 0 4px; }
.role { color: var(--fg-muted); margin: 0 0 12px; }
.bio { grid-area: bio; margin: 0; }   /* starts below the photo, full width */
.links {
  display: flex;
  flex-wrap: nowrap;            /* all links on one line, no scrolling */
  align-items: center;
  justify-content: space-between; /* spread across the full width to the right edge */
  gap: 10px;
  margin: 0;
  font-size: 0.85em;            /* base size for the row */
}
.links a { white-space: nowrap; }
.links .sep { color: var(--fg-muted); opacity: 0.6; }
.link-item { display: inline-flex; align-items: center; gap: 0.4em; }
/* uniform square box: every icon reads the same visual size and matches the text */
.ic { width: 1.05em; height: 1.05em; object-fit: contain; flex: 0 0 auto; }
.links .link-item:first-child { font-size: 1.25em; }   /* Email + its icon larger */
.ic-scholar { width: 1em; height: 1em; }                /* Google Scholar: a touch under the others */

@media (max-width: 560px) {
  .about-grid {
    grid-template-columns: 1fr;
    grid-template-areas: "photo" "header" "bio";
    text-align: center;
    row-gap: 16px;
  }
  .avatar-fig { justify-self: center; }
  .links { justify-content: center; }
}

/* =========================================================
   News
   ========================================================= */
.news-list { list-style: none; margin: 0; padding: 0; }
.news-list li {
  display: flex;
  gap: 16px;
  padding: 9px 0;
  border-bottom: 1px dashed var(--border);
}
.news-list li:last-child { border-bottom: none; }
.news-date {
  flex: 0 0 78px;
  color: var(--fg-muted);
  font-size: 15px;
  font-variant-numeric: tabular-nums;
  padding-top: 1px;
}

/* =========================================================
   Research
   ========================================================= */
.research-list { display: flex; flex-direction: column; gap: 26px; }
.research-item { display: flex; gap: 18px; }
.research-img {
  width: 160px;
  flex: 0 0 auto;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.research-item h3 { margin: 0 0 6px; font-size: 17px; }
.research-body p { margin: 0 0 8px; }
.research-items { margin: 14px 0 0; padding-left: 1.25em; list-style: disc; font-size: 16px; }
.research-items li { margin: 3px 0; }
.research-items li::marker { color: var(--fg-muted); }

@media (max-width: 560px) {
  .research-item { flex-direction: column; }
  .research-img { width: 100%; }
}

/* =========================================================
   Publications
   ========================================================= */
.pub-list { list-style: disc; margin: 0; padding-left: 1.4em; }
.pub { margin: 0 0 14px; line-height: 1.5; }
.pub::marker { color: var(--fg-muted); }
.pub-title { display: block; font-weight: 600; }
a.pub-title { color: inherit; text-decoration: none; }
a.pub-title:hover { color: var(--accent); text-decoration: underline; }
.pub-meta { display: block; font-size: 15px; }       /* authors + venue on one line */
.pub-authors { font-size: 15px; }
.pub-venue { color: var(--fg-muted); font-style: italic; }
.venue-key { color: var(--fg); font-weight: 700; font-style: italic; }   /* bold-black-italic conference tag */
.pub-note { color: var(--fg-muted); }
.pub-legend { margin: -12px 0 18px; font-size: 16px; color: var(--fg); }
.pub-award {
  display: inline-block;
  font-style: normal;
  font-size: 12.5px;
  color: var(--accent);
  border: 1px solid var(--accent);
  border-radius: 999px;
  padding: 0 8px;
  margin-left: 2px;
  vertical-align: 1px;
}
.pub-links { display: inline-flex; flex-wrap: wrap; gap: 8px; margin-left: 4px; vertical-align: baseline; }
.pub-links a {
  font-size: 13.5px;
  color: var(--fg-muted);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 1px 9px;
}
.pub-links a:hover { color: var(--accent); border-color: var(--accent); text-decoration: none; }

/* =========================================================
   Contact
   ========================================================= */
.services-list { list-style: disc; margin: 0; padding-left: 1.4em; }
.services-list li { margin: 0 0 8px; }
.contact-list li { display: flex; gap: 14px; padding: 5px 0; }
.contact-key {
  display: inline-flex;
  align-items: center;
  gap: 0.4em;
  flex: 0 0 auto;
  min-width: 140px;
  white-space: nowrap;
  color: var(--fg-muted);
}

@media (max-width: 460px) {
  .contact-list li { flex-direction: column; gap: 0; }
}

/* =========================================================
   Footer
   ========================================================= */
.footer { border-top: 1px solid var(--border); margin-top: 8px; }
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 24px 20px;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 8px 16px;
  color: var(--fg-muted);
  font-size: 13.5px;
}
.footer-inner a { color: var(--fg-muted); }
.footer-inner a:hover { color: var(--accent); }

/* =========================================================
   Reduced motion
   ========================================================= */
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
}