/* ============================================================
   Single column, typographic.
   Layout lives in .page (one measure, nothing sticky).
   ============================================================ */

:root {
  --bg:#ffffff; --fg:#27272a; --muted:#52525b; --faint:#71717a;
  --rule:#e4e4e7; --thumb-bg:#fafafa; --accent:#b45309;
  --card:#ffffff; --tag-l:32%; --tag-bg-l:96%; --tag-br-l:87%;
  --sans:"Figtree", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --serif:"Lora", Georgia, "Times New Roman", serif;
}

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

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--sans);
  font-size: 1rem;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, p, ol, ul, figure { margin: 0; }
ol, ul { list-style: none; padding: 0; }
img { display: block; max-width: 100%; height: auto; }

a { color: inherit; text-decoration: none; }

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

/* ---- the one measure ------------------------------------- */

.page {
  position: relative;
  max-width: 58rem;          /* 928px, wider than the original 800px */
  margin: 0 auto;
  padding: 0 1.5rem 4rem;
}

html { scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }

/* anchors land below the sticky nav rather than under it */
[id] { scroll-margin-top: 4.5rem; }

@media (max-width: 480px) {
  .page { padding: 3rem 1.25rem 3rem; }
}

/* ---- masthead -------------------------------------------- */

/* ---- top nav --------------------------------------------- */

.topnav {
  position: sticky;
  top: 0;
  z-index: 5;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 0.5rem 1.5rem;
  padding: 1.1rem 0;
  margin-bottom: 2.75rem;
  background: var(--bg);
  border-bottom: 1px solid var(--rule);
  font-size: 0.9rem;
}

.topnav-name { font-family: var(--serif); font-weight: 600; }

.topnav-links { display: flex; flex-wrap: wrap; gap: 0 1.1rem; }

.topnav-links a {
  color: var(--muted);
  text-decoration: underline;
  text-decoration-color: transparent;
  text-underline-offset: 4px;
  transition: color .12s ease, text-decoration-color .12s ease;
}

.topnav-links a:hover { color: var(--accent); text-decoration-color: var(--accent); }

.masthead {
  display: flex;
  align-items: flex-start;
  gap: 1.75rem;
  margin-bottom: 2.75rem;
}

.masthead-info { flex: 1; min-width: 0; }

.portrait {
  flex-shrink: 0;
  width: 9.5rem;
  aspect-ratio: 1;
  object-fit: cover;
  border-radius: 999px;
  background: var(--thumb-bg);
}

.name {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 2.125rem;
  line-height: 1.15;
  letter-spacing: -0.015em;
}

.role {
  margin-top: 0.85rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.role a {
  color: var(--fg);
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
}

.role a:hover { text-decoration-color: var(--accent); }

/* profile links: plain text, dot-separated, no pills */
.links {
  margin-top: 1.1rem;
  font-size: 0.9rem;
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 0 0.65rem;
}

.links a {
  color: var(--muted);
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
  transition: color .12s ease;
}

.links a:hover { color: var(--accent); text-decoration-color: var(--accent); }

.links a + a::before {
  content: "·";
  color: var(--rule);
  margin-right: 0.65rem;
  text-decoration: none;
  display: inline-block;
}

@media (max-width: 480px) {
  .masthead { flex-direction: column; align-items: flex-start; }
  .portrait { width: 6.5rem; }
}

/* ---- prose ----------------------------------------------- */

.about {
  padding-top: 2.25rem;
  border-top: 1px solid var(--rule);
  clear: both;
}

.about p + p { margin-top: 1rem; }

.about a {
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
}

.about a:hover { text-decoration-color: var(--accent); }

.about strong { font-weight: 600; }

/* ---- disclosure ("a bit more on that") -------------------- */

.more { margin-top: 1.1rem; }

.more > summary {
  display: inline-flex;
  align-items: baseline;
  gap: 0.4rem;
  cursor: pointer;
  list-style: none;
  font-size: 0.9rem;
  color: var(--muted);
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
  transition: color .12s ease;
}

/* the default disclosure triangle, in both engines */
.more > summary::-webkit-details-marker { display: none; }
.more > summary::marker { content: ""; }

.more > summary:hover { color: var(--accent); text-decoration-color: var(--accent); }

.more > summary::after {
  content: "\25B8";
  display: inline-block;
  font-size: 0.75em;
  color: var(--faint);
  transition: transform .15s ease;
}

.more[open] > summary::after { transform: rotate(90deg); }

.more-body {
  margin-top: 1rem;
  font-size: 0.9rem;
  color: var(--muted);
  overflow: hidden;
}

.more-body p + p { margin-top: 0.75rem; }

.more-body a {
  color: var(--fg);
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
}

.more-body a:hover { text-decoration-color: var(--accent); }

.other-list > li {
  position: relative;
  padding-left: 1rem;
  margin-bottom: 0.7rem;
  font-size: 0.94rem;
}

.other-list > li::before {
  content: "\2022";
  position: absolute;
  left: 0;
  color: var(--faint);
}

.other-list b { font-weight: 600; }

.other-list a {
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
}

.other-list a:hover { text-decoration-color: var(--accent); }

/* ---- section heads --------------------------------------- */

.section-head {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.25rem;
  margin-bottom: 1.25rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--rule);
}

.papers, .news, .other { margin-top: 3.25rem; }

/* ---- publications ---------------------------------------- */

/* Two-up card grid. Each card is a fixed shape so the row reads as a set. */
.paper-list {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
  align-items: stretch;
}

@media (min-width: 720px) {
  .paper-list { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

.paper {
  display: flex;
  flex-direction: column;
  min-width: 0;
  height: 100%;
  padding: 1.15rem;
  border: 1px solid var(--rule);
  border-radius: 0.9rem;
  background: var(--card);
}

/* THE fix for figures of different proportions: a fixed 16:9 window that the
   figure is cropped to fill, rather than each figure setting its own height. */
.preview {
  position: relative;
  display: block;
  aspect-ratio: 16 / 9;
  margin-bottom: 0.85rem;
  border-radius: 0.6rem;
  overflow: hidden;
  background: var(--thumb-bg);
  border: 1px solid var(--rule);
}

/* contain, not cover: these are research figures, and cropping one through
   the middle destroys the thing it is meant to show. The box stays a fixed
   16:9 either way, which is what makes the grid line up. */
.preview img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center;
  display: block;
  padding: 0.4rem;
  transition: transform .3s ease;
}

.preview:hover img { transform: scale(1.03); }

.title {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.02rem;
  line-height: 1.35;
  margin-bottom: 0.5rem;
}

.title a { text-decoration: underline; text-decoration-color: transparent; text-underline-offset: 3px; }
.title a:hover { text-decoration-color: var(--accent); }

.tags { display: flex; flex-wrap: wrap; gap: 0.35rem; margin-bottom: 0.5rem; }

/* One hue per category, expressed as a single number. */
.tag {
  --tag-h: 220;
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.45rem;
  border-radius: 0.35rem;
  font-size: 0.7rem;
  font-weight: 500;
  line-height: 1;
  color:            hsl(var(--tag-h) 48% var(--tag-l));
  background:       hsl(var(--tag-h) 52% var(--tag-bg-l));
  border: 1px solid hsl(var(--tag-h) 38% var(--tag-br-l));
}

.t-safety         { --tag-h: 2;   }
.t-synthetic-data { --tag-h: 28;  }
.t-posttraining   { --tag-h: 145; }
.t-tool-use       { --tag-h: 178; }
.t-pretraining    { --tag-h: 220; }
.t-tokenizer      { --tag-h: 265; }
.t-korean         { --tag-h: 330; }
.t-embedding      { --tag-h: 42;  }

.meta {
  font-size: 0.8rem;
  color: var(--faint);
  margin-bottom: 0.4rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0 0.5rem;
}

.meta > span + span::before { content: "\00b7"; margin-right: 0.5rem; color: var(--rule); }
.meta .award, .meta .toappear { color: var(--accent); font-weight: 600; }

.authors { font-size: 0.85rem; color: var(--muted); margin-bottom: 0.5rem; }
.authors .me { color: var(--fg); font-weight: 600; }
.authors a { text-decoration: underline; text-decoration-color: var(--rule); text-underline-offset: 2px; }
.authors a:hover { text-decoration-color: var(--accent); }

.tldr { font-size: 0.875rem; margin-bottom: 0.6rem; }
.tldr b { font-weight: 600; }

/* pinned to the bottom so link rows line up across a row of cards */
.links-row {
  margin-top: auto;
  padding-top: 0.3rem;
  font-size: 0.85rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0 0.6rem;
}

.links-row a {
  color: var(--muted);
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
}

.links-row a:hover { color: var(--accent); text-decoration-color: var(--accent); }
.links-row a + a::before { content: "\00b7"; color: var(--rule); margin-right: 0.6rem; }

.cofirst-note {
  margin-top: 1.75rem;
  font-size: 0.8125rem;
  color: var(--faint);
}

/* ---- updates --------------------------------------------- */

.news-list > li + li { margin-top: 0.7rem; }

.news-item {
  display: grid;
  grid-template-columns: 4.25rem minmax(0, 1fr);
  gap: 0.75rem;
  font-size: 0.9rem;
  align-items: baseline;
}

.news-item .what { grid-column: 2; grid-row: 1; }

.news-item .when {
  grid-column: 1;
  grid-row: 1;
  color: var(--faint);
  font-size: 0.8125rem;
  font-variant-numeric: tabular-nums;
}

.news-item .note { color: var(--muted); }
.news-item .note::before { content: ": "; }

.news-item .news-link {
  text-decoration: underline;
  text-decoration-color: var(--rule);
  text-underline-offset: 3px;
  transition: color .12s ease, text-decoration-color .12s ease;
}

.news-item .news-link:hover {
  color: var(--accent);
  text-decoration-color: var(--accent);
}

/* ---- footer ---------------------------------------------- */

.foot {
  margin-top: 4rem;
  padding-top: 1.25rem;
  border-top: 1px solid var(--rule);
  font-size: 0.8125rem;
  color: var(--faint);
}

.noscript {
  margin-top: 1.5rem;
  font-size: 0.9rem;
  color: var(--muted);
}

/* ---- print ----------------------------------------------- */

@media print {
  .preview, .portrait, .news { display: none; }
  .paper { border: none; padding: 0; }
  .paper-list { grid-template-columns: 1fr; }
  .page { max-width: none; padding: 0; }
  a { text-decoration: none; }
}