/* ============================================================
   STYLES — layout, typography, colors.
   Most editable knobs live in :root below as CSS variables.
   ============================================================ */

:root {
  /* Palette */
  --bg: #FAFAF7;
  --fg: #1a1a1a;
  --muted: #8a8780;
  --rule: #e8e5de;

  /* Accent (default: forest).
     Swap to one of these by uncommenting:
       indigo: oklch(55% 0.16 255) / oklch(96% 0.02 255) / oklch(85% 0.08 255)
       rust:   oklch(55% 0.16 40)  / oklch(96% 0.02 40)  / oklch(85% 0.08 40)
       forest: oklch(48% 0.12 150) / oklch(96% 0.02 150) / oklch(85% 0.08 150)
       plum:   oklch(48% 0.15 320) / oklch(96% 0.02 320) / oklch(85% 0.08 320)
       ink:    #1a1a1a             / #f0eee9             / #c8c5bd            */
  --accent: oklch(48% 0.12 150);
  --accent-bg: oklch(96% 0.02 150);
  --accent-underline: oklch(85% 0.08 150);

  /* Typography.
     --font-body options:
       Sans:  'Inter', -apple-system, system-ui, sans-serif
       Serif: 'Source Serif 4', Georgia, serif
       Mono:  'JetBrains Mono', ui-monospace, monospace         */
  --font-body: 'Inter', -apple-system, system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, monospace;
  --fs-body: 14px;

  /* Spacing (density = "airy").
     Compact:  --gap: 40px; --pad: 16px; --fs-body: 14.5px;
     Airy:     --gap: 80px; --pad: 32px; --fs-body: 15.5px;
     Spacious: --gap: 96px; --pad: 48px; --fs-body: 16px;       */
  --gap: 80px;
  --pad: 32px;
  --gutter: 40px;

  /* Content column width. Typical choices:
       narrow:  680px (snug, long-form reading)
       default: 780px
       wide:    900–1040px (more breathing room for tables/pubs) */
  --page-max-width: 720px;
}

html, body { margin: 0; padding: 0; min-height: 100%; background: var(--bg); }
body {
  font-family: var(--font-body);
  font-size: var(--fs-body);
  color: var(--fg);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}
* { box-sizing: border-box; }

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

/* ---- Layout ---- */
.page {
  max-width: var(--page-max-width);
  margin: 0 auto;
  padding: 120px var(--gutter) 120px;
}

/* ---- Side rail ---- */
.rail-wrap {
  position: fixed;
  top: 0; left: 0;
  width: 0; height: 100vh;
  z-index: 5;
  pointer-events: none;
}
.rail {
  position: absolute;
  top: 50%;
  left: 24px;
  transform: translate(-12px, -50%);
  opacity: 0;
  pointer-events: none;
  transition: opacity .3s ease, transform .3s ease;
  display: flex; flex-direction: column;
  gap: 2px;
  font-size: 12px;
  white-space: nowrap;
}
.rail.visible {
  transform: translate(0, -50%);
  opacity: 1;
  pointer-events: auto;
}
.rail a {
  display: flex; align-items: center; gap: 10px;
  color: var(--muted);
  font-weight: 400;
  padding: 4px 0;
  line-height: 1.2;
  letter-spacing: 0.1px;
  transition: color .18s, font-weight .18s;
  text-decoration: none;
}
.rail a:hover { text-decoration: none; color: var(--fg); }
.rail a .tick {
  width: 6px; height: 1px;
  background: #bbb;
  transition: width .2s, background .2s;
  flex-shrink: 0;
}
.rail a.active {
  color: var(--accent);
  font-weight: 600;
}
.rail a.active .tick {
  width: 16px;
  background: var(--accent);
}

/* ---- Hero ---- */
.hero {
  display: flex;
  gap: 40px;
  align-items: flex-start;
  margin-bottom: 36px;
}
.hero .photo {
  width: 120px; height: 120px;
  flex-shrink: 0;
  border-radius: 50%;
  background: repeating-linear-gradient(135deg, #e8e5de 0 6px, #ddd9d0 6px 12px);
  display: flex; align-items: center; justify-content: center;
  color: var(--muted);
  font-size: 10px;
  font-family: var(--font-mono);
  border: 1px solid var(--rule);
  overflow: hidden;
}
.hero .photo img { width: 100%; height: 100%; object-fit: cover; display: block; }
.hero .who { flex: 1; padding-top: 6px; }
.hero h1 {
  font-size: 24px;
  font-weight: 600;
  letter-spacing: -0.6px;
  margin: 0 0 8px;
}
.hero .role-line {
  color: var(--muted);
  font-size: 16px;
  margin-bottom: 20px;
}
.hero .link-row {
  display: flex;
  gap: 18px;
  flex-wrap: wrap;
  font-size: 14px;
}

/* ---- Section layout ---- */
section[data-sec] {
  padding-top: var(--gap);
  scroll-margin-top: 32px;
}
section[data-sec="about"] {
  padding-top: 0;
  padding-bottom: var(--gap);
}
.section-title {
  font-size: 13px;
  font-weight: 500;
  letter-spacing: 1.4px;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 24px;
}

/* ---- Entry (education / research / work / teaching / service) ---- */
.entry {
  display: grid;
  grid-template-columns: 170px 1fr;
  column-gap: 24px;
  margin-bottom: 22px;
}
.entry .left {
  color: var(--muted);
  font-size: 13px;
  font-variant-numeric: tabular-nums;
  padding-top: 2px;
  width: 170px;
  white-space: nowrap;
}
.entry .title { font-weight: 500; }
.entry .sub { color: var(--muted); font-size: 13px; }
.entry .detail {
  font-size: 13px;
  margin-top: 4px;
  color: var(--fg);
  white-space: pre-line;
}

/* ---- News grid ---- */
.news-grid {
  display: grid;
  grid-template-columns: 80px 1fr;
  row-gap: 12px;
  column-gap: 24px;
}
.news-grid .date {
  color: var(--muted);
  font-size: 14px;
  font-variant-numeric: tabular-nums;
}

/* ---- Publications ---- */
.pubs { display: flex; flex-direction: column; gap: 24px; }
.pub .pub-title { font-weight: 500; margin-bottom: 4px; line-height: 1.4; }
.pub .pub-authors { font-size: 13px; margin-bottom: 2px; }
.pub .pub-venue { font-size: 13px; font-style: italic; }

/* ---- About paragraphs ---- */
.about-body p { margin: 0 0 16px; }
.about-body p:last-child { margin-bottom: 0; }

/* ---- Footer ---- */
footer {
  margin-top: 80px;
  padding-top: 24px;
  border-top: 1px solid var(--rule);
  font-size: 13px;
  color: var(--muted);
  display: flex;
  justify-content: space-between;
}

/* ---- Mobile ---- */
@media (max-width: 640px) {
  :root { --gutter: 20px; --gap: 48px; --fs-body: 15px; }
  .page { padding: 72px var(--gutter) 96px; }
  .hero { flex-direction: column; gap: 20px; align-items: flex-start; }
  .hero .photo { width: 84px; height: 84px; }
  .hero h1 { font-size: 26px; }
  .entry { grid-template-columns: 1fr; }
  .entry .left {
    padding-top: 0;
    margin-bottom: 2px;
    font-size: 12.5px;
    width: auto;
  }
  .news-grid { grid-template-columns: 1fr; row-gap: 4px; }
  .news-grid .date {
    font-size: 12.5px;
  }
  .rail-wrap { display: none; }
  footer { flex-direction: column; gap: 6px; }
}