/* =========================================================
   Hanpeng Liu — personal homepage
   Layout idea: one narrow reading column with a left "index"
   column (dates, venues) shared by News, Publications and
   Experience, so the eye can scan years/venues top to bottom.
   ========================================================= */

/* ---------- Self-hosted fonts (no Google Fonts: loads fine in mainland China) ---------- */
@font-face {
  font-family: "Plex Sans";
  src: url("../fonts/ibm-plex-sans-latin-400-normal.woff2") format("woff2");
  font-weight: 400; font-style: normal; font-display: swap;
}
@font-face {
  font-family: "Plex Sans";
  src: url("../fonts/ibm-plex-sans-latin-400-italic.woff2") format("woff2");
  font-weight: 400; font-style: italic; font-display: swap;
}
@font-face {
  font-family: "Plex Sans";
  src: url("../fonts/ibm-plex-sans-latin-600-normal.woff2") format("woff2");
  font-weight: 600; font-style: normal; font-display: swap;
}
@font-face {
  font-family: "Plex Serif";
  src: url("../fonts/ibm-plex-serif-latin-500-normal.woff2") format("woff2");
  font-weight: 500; font-style: normal; font-display: swap;
}

/* ---------- Tokens ---------- */
:root {
  --paper: #ffffff;
  --ink: #18212b;        /* body text */
  --muted: #5a6472;      /* secondary text, author lists */
  --rule: #e2e6ec;       /* the few dividers we use */
  --tint: #eef4f3;       /* job-market note background */
  --accent: #0e7466;     /* viridian: links, venues, matrix diagonal */
  --cell: #c9d3dc;       /* off-diagonal matrix cells */

  --sans: "Plex Sans", "Helvetica Neue", Arial, "PingFang SC", "Microsoft YaHei", sans-serif;
  --serif: "Plex Serif", Georgia, "Songti SC", serif;

  --measure: 46rem;      /* reading column width (~75 characters per line) */
  --index: 7.5rem;       /* left index column for dates / venues */
  --gap: 1.5rem;
}

@media (prefers-color-scheme: dark) {
  :root {
    --paper: #10151b;
    --ink: #e4e9ef;
    --muted: #9aa5b3;
    --rule: #253040;
    --tint: #16232a;
    --accent: #4fc4ae;
    --cell: #2c3a48;
  }
  .photo { filter: brightness(0.9); }   /* tone down the white ID-photo background on dark pages */
}

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

img { max-width: 100%; height: auto; }   /* no image can push the layout wider than its column */

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

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1.0625rem;
  line-height: 1.6;
  font-variant-numeric: tabular-nums;   /* dates line up in the index column */
}

a {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.18em;
}
a:hover { text-decoration-thickness: 2px; }
a:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 3px;
  border-radius: 2px;
}

.wrap {
  max-width: var(--measure);
  margin: 0 auto;
  padding: 0 1rem;
}

/* ---------- Top bar ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1.5rem 0 0.5rem;
}
.topbar nav { display: flex; flex-wrap: wrap; gap: 0.25rem 1.25rem; }
.topbar nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.95rem;
}
.topbar nav a:hover { color: var(--ink); }

/* ---------- Similarity-matrix mark ----------
   A tiny image-text similarity matrix: the diagonal (matched pairs)
   lights up once on page load. */
.matrix { display: block; width: 44px; height: 44px; flex: none; }
.matrix rect { fill: var(--cell); }
.matrix .d {
  fill: var(--accent);
  animation: light 520ms ease-out both;
  /* --i is the cell's position on the diagonal (0–4), set inline in the HTML */
  animation-delay: calc(150ms + var(--i, 0) * 120ms);
}
@keyframes light {
  from { fill: var(--cell); opacity: 0.35; }
  to   { fill: var(--accent); opacity: 1; }
}
@media (prefers-reduced-motion: reduce) {
  .matrix .d { animation: none; }
}

/* ---------- Hero ---------- */
.hero {
  display: grid;
  grid-template-columns: 1fr 9.5rem;
  gap: 2rem;
  align-items: start;
  padding: 2rem 0 1rem;
}
.hero h1 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 2.75rem;
  line-height: 1.1;
  letter-spacing: -0.01em;
  margin: 0;
}
.hero .zh {
  font-family: var(--serif);
  font-size: 1.25rem;
  color: var(--muted);
  margin: 0.35rem 0 0;
}
.hero .role {
  margin: 0.9rem 0 0;
  color: var(--muted);
}
.hero p { margin: 1rem 0 0; }

.photo {
  width: 100%;
  height: auto;          /* override the height attribute so aspect-ratio applies */
  aspect-ratio: 3 / 4;
  object-fit: cover;
  border-radius: 6px;
  display: block;
}

.links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.25rem 1.25rem;
  margin: 1.1rem 0 0;
  padding: 0;
  list-style: none;
}

.links + .links { margin-top: 0.3rem; }   /* second row: profile links under the emails */

.market {
  margin: 1.4rem 0 0;
  padding: 0.85rem 1rem;
  background: var(--tint);
  border-radius: 6px;
}

/* ---------- Sections ---------- */
section { padding: 1.75rem 0 0; }
section h2 {
  font-family: var(--serif);
  font-weight: 500;
  font-size: 1.5rem;
  line-height: 1.25;
  margin: 0 0 1rem;
}
section h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin: 1.75rem 0 0.75rem;
}
.note { color: var(--muted); font-size: 0.9rem; margin: -0.5rem 0 1rem; }

/* Rows with a left index column (date or venue) */
.rows { list-style: none; margin: 0; padding: 0; }
.rows > li {
  display: grid;
  grid-template-columns: var(--index) 1fr;
  gap: var(--gap);
  padding: 0.55rem 0;
}
.rows > li > * { min-width: 0; }   /* let grid cells shrink instead of overflowing */
.rows .idx {
  color: var(--muted);
  font-size: 0.95rem;
  padding-top: 0.05rem;
}

/* News */
.news > li { padding: 0.35rem 0; }

/* Publications */
.pubs > li { padding: 0.8rem 0; }
.pubs .idx { color: var(--accent); font-weight: 600; }
.pub-title { font-weight: 600; line-height: 1.4; }
.pub-authors, .pub-venue { color: var(--muted); font-size: 0.95rem; margin-top: 0.2rem; }
.pub-authors strong { color: var(--ink); font-weight: 600; }
.pub-tldr { margin-top: 0.35rem; font-size: 0.98rem; }
.pub-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.2rem 1rem;
  margin-top: 0.35rem;
  font-size: 0.95rem;
}

/* Interests */
.interests { margin: 0; padding-left: 1.2rem; }
.interests li { margin: 0.2rem 0; }

/* Experience */
.org { font-weight: 600; }
.sub { color: var(--muted); font-size: 0.95rem; }

/* ---------- Footer ---------- */
footer {
  margin: 3rem 0 0;
  padding: 1.25rem 0 2.5rem;
  border-top: 1px solid var(--rule);
  color: var(--muted);
  font-size: 0.9rem;
}

/* ---------- Small screens ---------- */
@media (max-width: 640px) {
  body { font-size: 1rem; }
  .hero {
    grid-template-columns: 1fr;
    gap: 1.25rem;
    padding-top: 1.25rem;
  }
  .hero .photo-wrap { order: -1; width: 7.5rem; }   /* photo first, small */
  .hero h1 { font-size: 2.2rem; }
  .rows > li {
    grid-template-columns: 1fr;
    gap: 0.1rem;
  }
}

/* ---------- Publication figures ---------- */
.pub-fig { display: block; max-width: 28rem; margin: 0.65rem 0 0.15rem; }   /* thumbnail size; click opens the full figure */
.pub-fig img {
  display: block;
  width: 100%;
  height: auto;
  background: #fff;                 /* figures are drawn on white; keep that in dark mode too */
  border: 1px solid var(--rule);
  border-radius: 6px;
  padding: 0.5rem;
}
.pub-fig:focus-visible img { outline: 2px solid var(--accent); outline-offset: 2px; }

/* ---------- Compact list for the other papers ---------- */
.pubs.compact > li { padding: 0.45rem 0; }
.pubs.compact .idx { color: var(--muted); font-weight: 400; }
.pubs.compact .pub-title { font-size: 1rem; }
.pubs.compact .pub-authors em { color: var(--ink); }
.pubs.compact .pub-authors a { margin-left: 0.35rem; }

/* jump targets land below the top edge */
.pub { scroll-margin-top: 1rem; }