/* ============================================================
   Anna Chen — personal site
   One stylesheet. Palettes are CSS variables; swap via
   <html data-palette="oxide|lamont|umber|bordeaux|graphite">
   ============================================================ */

/* ---------- Palettes: light ---------- */
:root,
:root[data-palette="oxide"] {
  --bg:#FBF9F6; --bg2:#F3EFE9; --text:#1E1A17; --text2:#6B615A;
  --accent:#9A4A31; --accent2:#7A3823; --rule:#E4DDD4; --shadow:26 20 15;
}
:root[data-palette="lamont"] {
  --bg:#F9FAFB; --bg2:#EFF2F4; --text:#171B1F; --text2:#5D6771;
  --accent:#37596F; --accent2:#24404F; --rule:#DDE2E7; --shadow:15 20 26;
}
:root[data-palette="umber"] {
  --bg:#FAF7F1; --bg2:#F1EBE0; --text:#221D16; --text2:#6D6355;
  --accent:#7A5A34; --accent2:#5D4526; --rule:#E5DCCD; --shadow:26 22 15;
}
:root[data-palette="bordeaux"] {
  --bg:#FBF9F9; --bg2:#F2EDEE; --text:#191517; --text2:#675C60;
  --accent:#74303E; --accent2:#59222E; --rule:#E6DDDF; --shadow:25 18 20;
}
:root[data-palette="graphite"] {
  --bg:#F8F8F7; --bg2:#EEEEEC; --text:#16181A; --text2:#5F6467;
  --accent:#3B4348; --accent2:#23292D; --rule:#E1E1DE; --shadow:18 20 21;
}

/* ---------- Palettes: dark (system preference) ---------- */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]),
  :root[data-palette="oxide"]:not([data-theme="light"]) {
    --bg:#171513; --bg2:#201D1A; --text:#ECE7E1; --text2:#A79C93;
    --accent:#CE8163; --accent2:#E2A085; --rule:#312C27; --shadow:0 0 0;
  }
  :root[data-palette="lamont"]:not([data-theme="light"]) {
    --bg:#121517; --bg2:#1A1E21; --text:#E7EBEE; --text2:#97A2AB;
    --accent:#86ADC5; --accent2:#A4C4D8; --rule:#282D31; --shadow:0 0 0;
  }
  :root[data-palette="umber"]:not([data-theme="light"]) {
    --bg:#16140F; --bg2:#1E1B16; --text:#EBE5DA; --text2:#A69B8A;
    --accent:#C59C66; --accent2:#D8B584; --rule:#2F2B23; --shadow:0 0 0;
  }
  :root[data-palette="bordeaux"]:not([data-theme="light"]) {
    --bg:#151213; --bg2:#1D1919; --text:#EBE6E7; --text2:#A2969A;
    --accent:#BC7986; --accent2:#CE95A0; --rule:#2E2829; --shadow:0 0 0;
  }
  :root[data-palette="graphite"]:not([data-theme="light"]) {
    --bg:#131415; --bg2:#1B1C1E; --text:#E9EAEB; --text2:#9A9FA3;
    --accent:#AEB8BD; --accent2:#C7CFD3; --rule:#2A2C2E; --shadow:0 0 0;
  }
}

/* ---------- Secondary accent: dark forest green ----------
   Used for links, headings, funding/fellowship tags, and the
   location/type line of each presentation. Independent of palette. */
:root { --sec:#2E5D46; --sec2:#20452F; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) { --sec:#7FB396; --sec2:#9BC7AC; }
}

/* ---------- Reset & base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  font-size: 16.5px;
  line-height: 1.62;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: "kern" 1;
}
img { max-width: 100%; display: block; }
a { color: var(--sec); text-decoration: none; }
a:hover { color: var(--sec2); text-decoration: underline; text-underline-offset: 3px; }
h1, h2, h3, h4 {
  font-family: Newsreader, "Iowan Old Style", "Palatino Linotype", Palatino, Georgia, serif;
  font-weight: 400;
  letter-spacing: -0.012em;
  line-height: 1.2;
  margin: 0;
}
p { margin: 0 0 1.05em; }
::selection { background: var(--accent); color: var(--bg); }

/* ---------- Layout ---------- */
.wrap { width: 100%; max-width: 1080px; margin: 0 auto; padding-inline: 24px; }
.narrow { max-width: 760px; }
section { padding-block: 60px; }
.rule-top { border-top: 1px solid var(--rule); }

/* ---------- Header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 50;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  border-bottom: 1px solid var(--rule);
}
.site-header .wrap {
  display: flex; align-items: center; justify-content: space-between;
  gap: 20px; min-height: 62px;
}
.wordmark {
  font-family: Newsreader, "Iowan Old Style", Palatino, Georgia, serif;
  font-size: 1.18rem; color: var(--text); letter-spacing: -0.01em;
}
.wordmark:hover { text-decoration: none; color: var(--accent); }
.nav { display: flex; align-items: center; gap: 22px; flex-wrap: wrap; }
.nav a {
  color: var(--text2); font-size: 0.875rem; letter-spacing: 0.02em;
  padding-block: 4px; border-bottom: 1px solid transparent;
}
.nav a:hover { color: var(--text); text-decoration: none; border-bottom-color: var(--accent); }
.nav a[aria-current="page"] { color: var(--text); border-bottom-color: var(--accent); }
.nav a.cv-link { color: var(--sec); }
.nav a.cv-link::after { content: " ↓"; font-size: 0.8em; }

/* ---------- Hero ---------- */
.hero { padding-block: 76px 56px; }
.hero-grid {
  display: grid; grid-template-columns: minmax(0,1.45fr) minmax(0,1fr);
  gap: 56px; align-items: start;
}
.hero h1 { font-size: clamp(2.5rem, 6vw, 3.65rem); line-height: 1.06; margin-bottom: 6px; }
.hero h1 .cn {
  display: block; font-size: 0.5em; letter-spacing: 0.14em;
  color: var(--text2); margin-top: 12px; font-weight: 300;
}
.eyebrow {
  font-size: 0.775rem; letter-spacing: 0.15em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 20px; font-weight: 500;
}
.lede { font-size: 1.1rem; color: var(--text2); max-width: 54ch; }
.lede strong { color: var(--text); font-weight: 500; }
.portrait {
  width: 100%; height: auto; border-radius: 2px; aspect-ratio: 1/1; object-fit: cover;
  object-position: center 22%; border: 1px solid var(--rule);
}
.portrait-cap {
  font-size: 0.775rem; color: var(--text2); margin-top: 10px; line-height: 1.5;
}

/* ---------- Buttons ---------- */
.btn-row { display: flex; flex-wrap: wrap; gap: 12px; margin-top: 30px; }
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  font-size: 0.85rem; letter-spacing: 0.02em;
  padding: 10px 18px; border-radius: 2px;
  border: 1px solid var(--accent); color: var(--accent);
  background: transparent; transition: background .16s, color .16s;
}
.btn:hover { background: var(--accent); color: var(--bg); text-decoration: none; }
.btn-solid { background: var(--accent); color: var(--bg); }
.btn-solid:hover { background: var(--accent2); border-color: var(--accent2); color: var(--bg); }
.btn-quiet { border-color: var(--rule); color: var(--text2); }
.btn-quiet:hover { background: var(--bg2); color: var(--text); border-color: var(--text2); }

/* ---------- Section headings ---------- */
.sec-head { margin-bottom: 34px; }
.sec-head h2 { font-size: clamp(1.6rem, 3.4vw, 2.05rem); }
.sec-head .kicker {
  font-size: 0.75rem; letter-spacing: 0.16em; text-transform: uppercase;
  color: var(--accent); margin-bottom: 12px; font-weight: 500;
}
.sec-head p { color: var(--text2); max-width: 66ch; margin-top: 12px; }

/* ---------- Research-interests diagram ---------- */
.diagram-block { background: var(--bg2); border: 1px solid var(--rule); border-radius: 3px;
  padding: 26px 26px 20px; max-width: 760px; margin-inline: auto; }
.diagram-block svg { width: 100%; height: auto; }
.diagram-cap { font-size: 0.8rem; color: var(--text2); margin: 16px 0 0; line-height: 1.55; }
.svg-line { fill: none; stroke: var(--accent); stroke-width: 1.4; }
.svg-line-soft { fill: none; stroke: var(--text2); stroke-width: 1; }
.svg-fill { fill: var(--accent); }
.svg-fill-soft { fill: var(--text2); }
.svg-band { fill: var(--accent); opacity: 0.06; }
.svg-label { fill: var(--text); font-family: Inter, system-ui, sans-serif; font-size: 17px; }
.svg-label-sm { fill: var(--text2); font-family: Inter, system-ui, sans-serif; font-size: 15px; letter-spacing: 0.04em; }
.svg-num { fill: var(--bg); font-family: Inter, system-ui, sans-serif; font-size: 13.5px; font-weight: 600; }

/* ---------- Skills ---------- */
.skills-grid {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); gap: 30px 40px;
}
.skill-col h3 {
  font-size: 0.78rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--accent); font-family: Inter, system-ui, sans-serif; font-weight: 600;
  margin-bottom: 12px;
}
.skill-col ul { list-style: none; margin: 0; padding: 0; }
.skill-col li { padding: 5px 0; border-bottom: 1px solid var(--rule); font-size: 0.925rem; }
.skill-col li:last-child { border-bottom: 0; }
.skill-col li span { color: var(--text2); font-size: 0.86em; }

/* ---------- Research projects ---------- */
.project { padding-block: 56px; border-top: 1px solid var(--rule); }
.project:first-of-type { border-top: 0; padding-top: 8px; }
.proj-num {
  font-family: Newsreader, Georgia, serif; font-size: 0.95rem;
  color: var(--accent); letter-spacing: 0.1em; margin-bottom: 10px;
}
.project h2 { font-size: clamp(1.42rem, 3vw, 1.85rem); max-width: 46ch; }
.proj-meta {
  margin-top: 18px; display: flex; flex-wrap: wrap; gap: 8px 26px;
  font-size: 0.83rem; color: var(--text2);
}
.proj-meta b { font-weight: 500; color: var(--text); }
.tags { display: flex; flex-wrap: wrap; gap: 7px; margin-top: 16px; }
.tag {
  font-size: 0.72rem; letter-spacing: 0.06em; text-transform: uppercase;
  padding: 4px 10px; border: 1px solid var(--rule); border-radius: 2px;
  color: var(--text2); background: var(--bg2);
}
.tag-accent { color: var(--accent); border-color: color-mix(in srgb, var(--accent) 35%, var(--rule)); }
.tag-fund {
  color: var(--sec); border-color: color-mix(in srgb, var(--sec) 38%, var(--rule));
  background: color-mix(in srgb, var(--sec) 7%, var(--bg2));
}
.proj-body { display: grid; grid-template-columns: minmax(0,1fr) minmax(0,1fr); gap: 44px; margin-top: 30px; }
.role-box { border-left: 2px solid var(--accent); padding-left: 20px; }
.role-box h3 {
  font-size: 0.78rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--accent); font-family: Inter, system-ui, sans-serif; font-weight: 600; margin-bottom: 10px;
}
.role-box p { font-size: 0.95rem; }

/* ---------- Figures & media ---------- */
.fig { margin: 30px 0 0; }
.fig-frame {
  border: 1px solid var(--rule); background: #fff; border-radius: 2px;
  padding: 10px; cursor: zoom-in; transition: border-color .16s;
}
.fig-frame:hover { border-color: var(--accent); }
.fig-frame img { width: 100%; }
.fig figcaption { font-size: 0.78rem; color: var(--text2); margin-top: 10px; line-height: 1.55; }
.fig-two { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.zoom-hint {
  font-size: 0.72rem; letter-spacing: 0.06em; color: var(--text2);
  text-transform: uppercase; margin-top: 8px;
}

/* ---------- Resource row (abstract / poster / data) ---------- */
.resources { margin-top: 34px; border-top: 1px solid var(--rule); padding-top: 24px; }
.resources h3 {
  font-size: 0.78rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--text2); font-family: Inter, system-ui, sans-serif; font-weight: 600; margin-bottom: 16px;
}
.res-grid { display: grid; grid-template-columns: minmax(0,1.32fr) minmax(0,1fr); gap: 34px; align-items: start; }
.res-right { display: flex; flex-direction: column; gap: 26px; }
.res-list { margin: 8px 0 0; padding-left: 17px; font-size: 0.8rem; color: var(--text2); line-height: 1.5; }
.res-list li { margin-bottom: 6px; }
.res-list li::marker { color: var(--sec); }
.res-heading { font-size: 0.8rem; color: var(--text); font-weight: 500; margin: 0; }
.poster-card { }
.poster-thumb {
  border: 1px solid var(--rule); border-radius: 2px; overflow: hidden;
  background: #fff; cursor: zoom-in; display: block; transition: border-color .16s;
  aspect-ratio: 1140/1000;
}
.poster-thumb:hover { border-color: var(--accent); }
.poster-thumb img { width: 100%; height: 100%; object-fit: cover; object-position: top center; }
.poster-label { font-size: 0.8rem; color: var(--text2); margin-top: 9px; line-height: 1.5; }
.poster-label a { font-size: 0.95em; }

/* ---------- Abstract toggle ---------- */
details.abstract {
  border: 1px solid var(--rule); border-radius: 2px; background: var(--bg2);
  padding: 0; margin-top: 4px;
}
details.abstract > summary {
  list-style: none; cursor: pointer; padding: 13px 16px;
  font-size: 0.83rem; letter-spacing: 0.03em; color: var(--accent);
  display: flex; align-items: center; gap: 9px; user-select: none;
}
details.abstract > summary::-webkit-details-marker { display: none; }
details.abstract > summary::before {
  content: "+"; font-size: 1.05rem; line-height: 1; width: 13px;
  display: inline-block; text-align: center;
}
details.abstract[open] > summary::before { content: "–"; }
details.abstract[open] > summary { border-bottom: 1px solid var(--rule); }
.abstract-body { padding: 16px; font-size: 0.9rem; color: var(--text2); }
.abstract-body p:last-child { margin-bottom: 0; }
.abstract-body .session {
  font-size: 0.78rem; color: var(--text2); border-top: 1px solid var(--rule);
  padding-top: 12px; margin-top: 14px;
}
.abstract-body .session b { color: var(--text); font-weight: 500; }

/* ---------- Entry lists (pubs, awards, activities) ---------- */
.entry { padding: 22px 0; border-bottom: 1px solid var(--rule); display: grid;
  grid-template-columns: 130px minmax(0,1fr); gap: 10px 28px; }
.entry:last-child { border-bottom: 0; }
.entry-date { font-size: 0.8rem; color: var(--text2); letter-spacing: 0.03em; padding-top: 3px; }
.entry h3 {
  font-size: 1.06rem; margin-bottom: 10px; color: var(--text);
  display: inline-block; border-radius: 2px;
  padding: 4px 10px; margin-left: -10px;
  background: color-mix(in srgb, #2E7D57 17%, var(--bg));
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .entry h3 {
    background: color-mix(in srgb, #7FB396 18%, var(--bg));
  }
}
.entry .sub {
  font-size: 0.875rem; margin-bottom: 8px;
  color: color-mix(in srgb, var(--sec) 76%, var(--text2));
}
.entry .sub .amount { color: var(--text2); }
.entry p { font-size: 0.9rem; color: var(--text2); margin-bottom: 0; }
.entry ul { margin: 8px 0 0; padding-left: 18px; font-size: 0.9rem; color: var(--text2); }
.entry ul li { margin-bottom: 4px; }
.citation { font-size: 0.94rem; line-height: 1.6; }
.citation b { font-weight: 600; color: var(--text); }
.status {
  display: inline-block; font-size: 0.7rem; letter-spacing: 0.07em; text-transform: uppercase;
  color: var(--accent); border: 1px solid color-mix(in srgb, var(--accent) 35%, var(--rule));
  padding: 2px 8px; border-radius: 2px; margin-left: 2px; vertical-align: 2px;
}
.amount { color: var(--text2); font-size: 0.9em; }

/* ---------- Photo gallery ---------- */
.gallery { display: grid; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); gap: 22px; }
.gal-item figure { margin: 0; }
.gal-item img {
  width: 100%; aspect-ratio: 4/3; object-fit: cover; border-radius: 2px;
  border: 1px solid var(--rule); cursor: zoom-in; transition: border-color .16s;
}
.gal-item img:hover { border-color: var(--accent); }
.gal-item figcaption { font-size: 0.8rem; color: var(--text2); margin-top: 9px; line-height: 1.5; }
.gallery-tall .gal-item img { aspect-ratio: 3/4; }

/* ---------- Contact ---------- */
.contact-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px,1fr)); gap: 34px; }
.contact-block h3 {
  font-size: 0.78rem; letter-spacing: 0.14em; text-transform: uppercase;
  color: var(--accent); font-family: Inter, system-ui, sans-serif; font-weight: 600; margin-bottom: 12px;
}
.contact-block p { font-size: 0.95rem; color: var(--text2); }
.contact-block a { word-break: break-word; }

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--rule); padding-block: 30px; margin-top: 40px;
  font-size: 0.82rem; color: var(--text2);
}
.site-footer .wrap { display: flex; flex-wrap: wrap; gap: 12px 26px; justify-content: space-between; }
.site-footer a { color: var(--text2); }
.site-footer a:hover { color: var(--sec); }

/* ---------- Lightbox ---------- */
.lightbox {
  position: fixed; inset: 0; z-index: 100;
  background: rgba(12,10,9,0.93);
  display: flex; align-items: center; justify-content: center;
  padding: 28px; overflow: auto;
}
.lightbox img { max-width: 100%; max-height: 92vh; width: auto; object-fit: contain; border-radius: 2px; }
.lightbox.zoomed { align-items: flex-start; justify-content: flex-start; cursor: zoom-out; }
.lightbox.zoomed img { max-width: none; max-height: none; width: 2400px; }
.lb-close {
  position: fixed; top: 16px; right: 20px; z-index: 101;
  background: none; border: 1px solid rgba(255,255,255,0.35); color: #fff;
  font-size: 0.8rem; letter-spacing: 0.08em; padding: 7px 14px; border-radius: 2px;
  cursor: pointer; font-family: Inter, system-ui, sans-serif;
}
.lb-close:hover { border-color: #fff; }
.lb-hint {
  position: fixed; bottom: 18px; left: 50%; transform: translateX(-50%);
  color: rgba(255,255,255,0.6); font-size: 0.75rem; letter-spacing: 0.06em;
  font-family: Inter, system-ui, sans-serif;
}

/* ---------- Skip link ---------- */
.skip {
  position: absolute; left: -9999px; top: 0; background: var(--accent); color: var(--bg);
  padding: 10px 16px; z-index: 200;
}
.skip:focus { left: 8px; top: 8px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; }

/* ---------- Responsive ---------- */
@media (max-width: 900px) {
  .hero-grid { grid-template-columns: 1fr; gap: 36px; }
  .portrait { max-width: 340px; }
  .proj-body { grid-template-columns: 1fr; gap: 26px; }
  .res-grid { grid-template-columns: 1fr; gap: 28px; }
}
@media (max-width: 640px) {
  body { font-size: 16px; }
  section { padding-block: 44px; }
  .hero { padding-block: 46px 34px; }
  .wrap { padding-inline: 18px; }
  .site-header .wrap { flex-direction: column; align-items: flex-start; gap: 6px; padding-block: 10px; }
  .nav { gap: 16px; }
  .entry { grid-template-columns: 1fr; gap: 4px; }
  .entry-date { padding-top: 0; }
  .fig-two { grid-template-columns: 1fr; }
  .lightbox { padding: 12px; }
}

@media print {
  .site-header, .site-footer, .palette-bar, .lightbox { display: none !important; }
  body { background: #fff; color: #000; }
}