/* ---------- Fonts (self-hosted so the page loads well in mainland China) ---------- */
@font-face { font-family: "Spectral"; font-style: normal; font-weight: 300; font-display: swap; src: url("../fonts/spectral-latin-300-normal.woff2") format("woff2"); }
@font-face { font-family: "Spectral"; font-style: normal; font-weight: 400; font-display: swap; src: url("../fonts/spectral-latin-400-normal.woff2") format("woff2"); }
@font-face { font-family: "Spectral"; font-style: italic; font-weight: 400; font-display: swap; src: url("../fonts/spectral-latin-400-italic.woff2") format("woff2"); }
@font-face { font-family: "Spectral"; font-style: normal; font-weight: 500; font-display: swap; src: url("../fonts/spectral-latin-500-normal.woff2") format("woff2"); }
@font-face { font-family: "Spectral"; font-style: normal; font-weight: 600; font-display: swap; src: url("../fonts/spectral-latin-600-normal.woff2") format("woff2"); }
/* Three glyphs only: 吴 恩 楠 (Noto Serif SC, SemiBold) */
@font-face { font-family: "Name Hanzi"; font-weight: 600; font-display: block; src: url("../fonts/name-1.woff2") format("woff2"); unicode-range: U+5434; }
@font-face { font-family: "Name Hanzi"; font-weight: 600; font-display: block; src: url("../fonts/name-2.woff2") format("woff2"); unicode-range: U+6069; }
@font-face { font-family: "Name Hanzi"; font-weight: 600; font-display: block; src: url("../fonts/name-0.woff2") format("woff2"); unicode-range: U+6960; }

/* ---------- Tokens ---------- */
:root {
  --slate: #333437;        /* matched to the portrait background */
  --slate-ink: #eceeea;
  --slate-muted: #a9aeab;
  --paper: #f1f2ef;
  --ink: #1c1e20;
  --muted: #5b6063;
  --rule: #d4d7d2;
  --accent: #2c675c;       /* celadon, for links on paper */
  --accent-soft: #b6d3c7;  /* celadon, on slate */
  --serif: "Spectral", "Noto Serif SC", "Source Han Serif SC", "Songti SC", "STSong", "PingFang SC", "Microsoft YaHei", Georgia, serif;
  --measure: 40rem;
  --gutter: 16px;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root {
    --paper: #18191b;
    --ink: #e3e5e1;
    --muted: #a2a8a8;
    --rule: #34373a;
    --accent: #9cc7b8;
    color-scheme: dark;
  }
}

/* ---------- Base ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; scroll-padding-top: 1.5rem; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--serif);
  font-size: 1.125rem;
  line-height: 1.65;
  font-feature-settings: "kern", "liga", "onum";
  text-rendering: optimizeLegibility;
}
img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 0.18em; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 3px; border-radius: 2px; }
.hero :focus-visible { outline-color: var(--accent-soft); }
i, em { font-style: italic; }
b, strong { font-weight: 600; }

/* Language switching: elements carry .en or .zh */
html[data-lang="zh"] .en { display: none !important; }
html:not([data-lang="zh"]) .zh { display: none !important; }
html[data-lang="zh"] body { line-height: 1.8; }

.skip { position: absolute; left: -999px; top: 0; background: var(--paper); color: var(--ink); padding: .5rem 1rem; z-index: 10; }
.skip:focus { left: 1rem; top: 1rem; }

.wrap { max-width: 70rem; margin: 0 auto; padding: 0 var(--gutter); }
@media (min-width: 640px) { :root { --gutter: 32px; } }

/* ---------- Hero ---------- */
.hero { background: var(--slate); color: var(--slate-ink); overflow: hidden; }
.hero a { color: var(--slate-ink); }

.topbar { display: flex; align-items: center; justify-content: space-between; gap: 1rem; padding-top: 1.25rem; padding-bottom: 1.25rem; }
.brand { font-size: 1.05rem; font-weight: 500; text-decoration: none; letter-spacing: .01em; white-space: nowrap; }
.nav { display: flex; align-items: center; gap: 1.5rem; }
.nav ul { list-style: none; display: flex; gap: 1.35rem; margin: 0; padding: 0; }
.nav ul a { text-decoration: none; color: var(--slate-muted); font-size: 1rem; }
.nav ul a:hover { color: var(--slate-ink); }
.lang {
  flex: none; white-space: nowrap;
  font: inherit; font-size: .95rem; color: var(--slate-ink); background: transparent; cursor: pointer;
  border: 1px solid rgba(236,238,234,.35); border-radius: 999px; padding: .2rem .8rem; min-width: 3.6rem;
}
.lang:hover { border-color: var(--accent-soft); color: var(--accent-soft); }

.hero-grid {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) minmax(0, 23rem);
  column-gap: clamp(1.5rem, 4vw, 3.5rem);
  align-items: end;
  padding-top: clamp(1.5rem, 5vw, 4rem);
}
.hanzi {
  writing-mode: vertical-rl;
  font-family: "Name Hanzi", "Noto Serif SC", "Source Han Serif SC", "Songti SC", serif;
  font-weight: 600;
  font-size: clamp(4.25rem, 9vw, 8.5rem);
  line-height: 1;
  letter-spacing: .12em;
  color: var(--accent-soft);
  margin: 0;
  align-self: start;
  padding-bottom: 3rem;
}
.intro { padding-bottom: clamp(2.5rem, 6vw, 5rem); max-width: 34rem; }
.intro h1 { font-weight: 300; font-size: clamp(2.75rem, 6vw, 4.6rem); line-height: 1.02; letter-spacing: -.012em; margin: 0 0 1.25rem; }
.role { margin: 0; font-size: 1.3rem; line-height: 1.4; }
.unit { margin: .2rem 0 0; color: var(--slate-muted); font-size: 1.05rem; line-height: 1.5; }
.summary { margin: 1.75rem 0 0; font-size: 1.1rem; line-height: 1.6; max-width: 30rem; text-wrap: pretty; }
.hero-links { display: flex; flex-wrap: wrap; gap: .5rem 1.5rem; margin: 1.75rem 0 0; padding: 0; list-style: none; font-size: 1rem; }
.hero-links a { color: var(--accent-soft); }

.portrait { margin: 0; align-self: end; }
.portrait img {
  width: 100%; height: auto; aspect-ratio: 2 / 3; object-fit: cover;
  /* Fade the photo's own grey backdrop into the slate band */
  -webkit-mask-image: linear-gradient(to right, transparent 0, #000 16%, #000 84%, transparent 100%), linear-gradient(to bottom, transparent 0, #000 18%);
          mask-image: linear-gradient(to right, transparent 0, #000 16%, #000 84%, transparent 100%), linear-gradient(to bottom, transparent 0, #000 18%);
  -webkit-mask-composite: source-in;
          mask-composite: intersect;
  margin-bottom: -1px;
}

@media (max-width: 899px) {
  .topbar { flex-wrap: wrap; }
  .nav { width: 100%; justify-content: space-between; }
  .nav ul { overflow-x: auto; gap: 1.1rem; scrollbar-width: none; -webkit-overflow-scrolling: touch; padding-bottom: 2px; }
  .nav ul::-webkit-scrollbar { display: none; }
  .nav ul a { white-space: nowrap; }
  .brand { display: none; }
  .hero-grid { grid-template-columns: auto minmax(0, 1fr); padding-top: .5rem; }
  .portrait { grid-column: 1 / -1; grid-row: 1; justify-self: center; width: min(74%, 20rem); margin-bottom: -2.5rem; }
  .portrait img {
    -webkit-mask-image: linear-gradient(to right, transparent 0, #000 16%, #000 84%, transparent 100%), linear-gradient(to bottom, transparent 0, #000 16%, #000 80%, transparent 100%);
            mask-image: linear-gradient(to right, transparent 0, #000 16%, #000 84%, transparent 100%), linear-gradient(to bottom, transparent 0, #000 16%, #000 80%, transparent 100%);
  }
  .hanzi { grid-row: 2; font-size: clamp(3rem, 15vw, 4.5rem); padding: .4rem 0 2rem; }
  .intro { grid-row: 2; padding-top: .4rem; }
  .intro h1 { font-size: clamp(2.4rem, 10vw, 3.2rem); }
  .role { font-size: 1.15rem; }
}

/* ---------- Sections ---------- */
main { padding-bottom: 2rem; }
.section {
  display: grid;
  grid-template-columns: 12rem minmax(0, 1fr);
  column-gap: 3rem;
  padding: 3.5rem 0;
  border-top: 1px solid var(--rule);
}
main > .section:first-child { border-top: 0; }
.section > h2 {
  margin: 0; font-weight: 500; font-size: 1.55rem; line-height: 1.25; letter-spacing: -.005em;
  align-self: start; position: sticky; top: 1.5rem;
}
.section-body { max-width: var(--measure); min-width: 0; }
.section-body > :first-child { margin-top: 0; }
h3 { font-weight: 500; font-size: 1.2rem; line-height: 1.35; margin: 2.5rem 0 1rem; }
.note { color: var(--muted); font-size: 1rem; margin: -.5rem 0 1.25rem; }
p { margin: 0 0 1.1rem; }

@media (max-width: 799px) {
  .section { grid-template-columns: 1fr; padding: 2.5rem 0; }
  .section > h2 { position: static; margin-bottom: 1.4rem; font-size: 1.45rem; }
}

/* Interests */
.interests { list-style: none; padding: 0; margin: 2rem 0 0; display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1rem 2rem; }
.interests li { border-left: 2px solid var(--accent); padding: .1rem 0 .1rem .9rem; line-height: 1.45; font-size: 1.02rem; }
@media (max-width: 520px) { .interests { grid-template-columns: 1fr; } }

/* Dated lists: news, talks, awards, timeline */
.dated { list-style: none; padding: 0; margin: 0; }
.dated > li { display: grid; grid-template-columns: 6.25rem minmax(0, 1fr); column-gap: 1.25rem; padding: .7rem 0; border-bottom: 1px solid var(--rule); }
.dated > li:first-child { padding-top: 0; }
.dated > li:last-child { border-bottom: 0; }
.when { color: var(--muted); font-size: .98rem; font-variant-numeric: lining-nums tabular-nums; padding-top: .12rem; }
.dated p { margin: 0; }
.meta { display: block; color: var(--muted); font-size: 1rem; line-height: 1.5; margin-top: .15rem; }
.badge { color: var(--accent); }
@media (max-width: 520px) {
  .dated > li { grid-template-columns: 1fr; }
  .when { padding-top: 0; }
}

/* Publications */
.pubs { list-style: none; padding: 0; margin: 0; }
.pubs > li { display: grid; grid-template-columns: 5rem minmax(0, 1fr); column-gap: 1.25rem; padding: .85rem 0; border-bottom: 1px solid var(--rule); font-size: 1.05rem; line-height: 1.55; }
.pubs > li:last-child { border-bottom: 0; }
.pubs .when { padding-top: .08rem; }
.pubs .t { display: block; color: var(--ink); }
.pubs .src { display: block; color: var(--muted); font-size: .98rem; margin-top: .2rem; }
.pubs .src i, .pubs .src b { color: var(--ink); }
.doi { font-size: .95rem; white-space: nowrap; }
.dagger { color: var(--accent); }
@media (max-width: 520px) { .pubs > li { grid-template-columns: 1fr; } }

/* Video */
.video { margin: 0 0 2.5rem; }
.video-frame {
  position: relative; aspect-ratio: 16 / 9; width: 100%;
  background: var(--slate); border-radius: 6px; overflow: hidden;
}
.video-frame img, .video-frame iframe { position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; border: 0; }
.video-frame img { opacity: .82; transition: opacity .2s ease; }
.video-fallback {
  position: absolute; inset: 0; display: flex; flex-direction: column; justify-content: flex-end;
  padding: clamp(1rem, 4vw, 2rem); color: var(--slate-ink);
  background: radial-gradient(ellipse 80% 90% at 70% 30%, #45474b 0, var(--slate) 70%);
}
.video-fallback strong { font-weight: 300; font-size: clamp(1.6rem, 5vw, 2.6rem); line-height: 1.05; letter-spacing: -.01em; }
.video-fallback span { color: var(--accent-soft); font-size: 1rem; margin-top: .4rem; }
.play {
  position: absolute; inset: 0; display: grid; place-items: center; width: 100%; height: 100%;
  background: transparent; border: 0; cursor: pointer; padding: 0; color: var(--slate);
}
.play span {
  width: 4.5rem; height: 4.5rem; border-radius: 50%; background: var(--accent-soft);
  display: grid; place-items: center; box-shadow: 0 0 0 10px rgba(182,211,199,.22);
  transition: transform .2s ease;
}
.play svg { width: 1.6rem; height: 1.6rem; margin-left: .25rem; }
.play:hover span, .play:focus-visible span { transform: scale(1.06); }
.video-frame:hover img { opacity: 1; }
.video figcaption { margin-top: 1rem; }
.video .vt { display: block; font-size: 1.2rem; line-height: 1.35; font-weight: 500; }
.video .vm { display: block; color: var(--muted); font-size: 1rem; margin-top: .25rem; }
.video p { margin: .75rem 0 0; }
@media (prefers-reduced-motion: reduce) { .play span, .video-frame img { transition: none; } }

/* Two-column facts */
.facts { display: grid; grid-template-columns: 9rem minmax(0, 1fr); gap: .6rem 1.25rem; margin: 0; }
.facts dt { color: var(--muted); font-size: 1rem; padding-top: .1rem; }
.facts dd { margin: 0; }
@media (max-width: 520px) { .facts { grid-template-columns: 1fr; } .facts dd { margin-bottom: .6rem; } }

/* Footer */
.footer { background: var(--slate); color: var(--slate-ink); }
.footer a { color: var(--accent-soft); }
.footer .wrap { display: grid; grid-template-columns: 12rem minmax(0, 1fr); column-gap: 3rem; padding-top: 3.5rem; padding-bottom: 3rem; }
.footer h2 { margin: 0; font-weight: 500; font-size: 1.55rem; }
.contact { margin: 0; display: grid; grid-template-columns: 8rem minmax(0, 1fr); gap: .55rem 1.25rem; max-width: var(--measure); }
.contact dt { color: var(--slate-muted); font-size: 1rem; padding-top: .1rem; }
.contact dd { margin: 0; }
.fineprint { grid-column: 2; color: var(--slate-muted); font-size: .95rem; margin: 2.5rem 0 0; }
@media (max-width: 799px) {
  .footer .wrap { grid-template-columns: 1fr; }
  .footer h2 { margin-bottom: 1.4rem; font-size: 1.45rem; }
  .fineprint { grid-column: 1; }
}
@media (max-width: 420px) { .contact { grid-template-columns: 1fr; gap: 0; } .contact dd { margin-bottom: .8rem; } }

/* Index tags on publications (SSCI, CSSCI, ...) */
.tags { display: flex; flex-wrap: wrap; gap: .35rem; margin-top: .5rem; }
.tag {
  font-size: .8rem; line-height: 1.45; padding: .08rem .5rem; border-radius: 3px;
  color: var(--accent); border: 1px solid var(--rule);
  background: color-mix(in srgb, var(--accent) 8%, transparent);
  font-variant-numeric: lining-nums; white-space: nowrap;
}