/* Personal academic site — Shaoliang Yang */
:root {
  --ink: #1c1b1a;
  --ink-2: #4a4744;
  --muted: #76716b;
  --paper: #fbfaf7;
  --band: #f3f0ea;
  --rule: #e4dfd6;
  --accent: #862633;        /* Santa Clara red */
  --accent-soft: #f4e8e9;
  --serif: "Newsreader", "Iowan Old Style", Georgia, serif;
  --sans: "Inter", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --maxw: 1080px;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 72px; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font: 16.5px/1.65 var(--sans);
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}
a { color: var(--accent); text-decoration: none; border-bottom: 1px solid transparent; transition: border-color .15s; }
a:hover { border-bottom-color: currentColor; }
img { max-width: 100%; height: auto; display: block; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 28px; }

/* ---------- top bar ---------- */
.topbar {
  position: sticky; top: 0; z-index: 10;
  background: rgba(251, 250, 247, .88);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--rule);
}
.topbar-inner { display: flex; align-items: center; justify-content: space-between; height: 58px; }
.brand { font: 600 19px/1 var(--serif); color: var(--ink); letter-spacing: .01em; border: 0; }
.brand:hover { border: 0; color: var(--accent); }
nav { display: flex; gap: 26px; }
nav a { color: var(--ink-2); font-size: 14.5px; font-weight: 500; border: 0; }
nav a:hover { color: var(--accent); border: 0; }

/* ---------- headings ---------- */
h1, h2, h3 { font-family: var(--serif); font-weight: 500; color: var(--ink); letter-spacing: -.01em; }
h1 { font-size: clamp(40px, 5.4vw, 60px); line-height: 1.05; margin: .15em 0 .25em; }
h2 { font-size: 34px; line-height: 1.15; margin: 0 0 .4em; }
h3 { font-size: 23px; line-height: 1.25; margin: .2em 0 .5em; }
h3.small { font: 600 12.5px/1.4 var(--sans); letter-spacing: .1em; text-transform: uppercase; color: var(--muted); margin: 1.8em 0 .7em; }
.eyebrow { font-size: 12.5px; font-weight: 600; letter-spacing: .12em; text-transform: uppercase; color: var(--accent); margin: 0; }
.lede { font: 400 23px/1.4 var(--serif); color: var(--ink); margin: 0 0 1em; }
.section-lede { font-size: 18px; color: var(--ink-2); max-width: 760px; margin: 0 0 2.4em; }

/* ---------- hero ---------- */
.hero {
  display: grid; grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr);
  gap: 56px; align-items: center; padding-top: 72px; padding-bottom: 80px;
}
.hero-text p { color: var(--ink-2); max-width: 620px; }
.hero-card {
  background: #fff; border: 1px solid var(--rule); border-radius: 16px; padding: 6px 26px 22px;
  border-top: 3px solid var(--accent);
}
.hero-card h3.small { margin-top: 1.4em; }
.edu { list-style: none; padding: 0; margin: 0; }
.edu li { padding: 8px 0; border-bottom: 1px solid var(--rule); font-size: 15px; }
.edu li:last-child, .hero-card .plain li:last-child { border-bottom: 0; }
.edu strong { display: block; font-weight: 500; color: var(--ink); }
.edu span { font-size: 14px; color: var(--muted); }

.links { list-style: none; padding: 0; margin: 1.8em 0 0; display: flex; flex-wrap: wrap; gap: 10px; }
.btn {
  display: inline-block; padding: 8px 15px; border-radius: 999px;
  border: 1px solid var(--rule); background: #fff;
  color: var(--ink); font-size: 14px; font-weight: 500;
}
.btn:hover { border-color: var(--accent); color: var(--accent); }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #fff; }
.btn.primary:hover { background: #6d1e29; color: #fff; }

/* ---------- sections ---------- */
section { padding: 80px 0; }
section.wrap { padding-top: 80px; padding-bottom: 80px; }
.band { background: var(--band); border-top: 1px solid var(--rule); border-bottom: 1px solid var(--rule); }

/* ---------- research threads ---------- */
.thread {
  display: grid; grid-template-columns: minmax(0, 1fr) minmax(0, 1.05fr);
  gap: 52px; align-items: center; padding: 44px 0; border-top: 1px solid var(--rule);
}
.thread.reverse .thread-text { order: 2; }
.thread-num { font: 500 15px/1 var(--serif); color: var(--accent); letter-spacing: .08em; margin: 0 0 6px; }
.thread-text p { color: var(--ink-2); }
.refs { font-size: 14px; color: var(--muted) !important; border-left: 2px solid var(--accent); padding-left: 12px; }
.thread-fig { margin: 0; background: #fff; border-radius: 14px; padding: 18px; border: 1px solid var(--rule); }
.thread-fig figcaption { font-size: 13px; color: var(--muted); margin-top: 12px; }
.aside { font: italic 400 19px/1.5 var(--serif); color: var(--ink-2); max-width: 820px; margin: 40px 0 0; padding-top: 32px; border-top: 1px solid var(--rule); }

/* controller diagram */
.diagram svg { width: 100%; height: auto; color: var(--ink-2); }
.diagram .node rect { fill: var(--paper); stroke: var(--rule); stroke-width: 1.5; }
.diagram .node.accent rect { fill: var(--accent-soft); stroke: var(--accent); }
.diagram .node.check rect { fill: #eef3ee; stroke: #6f8f72; }
.diagram text { font: 600 15px var(--sans); fill: var(--ink); text-anchor: middle; }
.diagram text.sub { font: 400 11.5px var(--sans); fill: var(--muted); }
.diagram text.motto { font: italic 400 16px var(--serif); fill: var(--accent); }
.diagram .edge { stroke: var(--ink-2); stroke-width: 1.6; fill: none; }

/* spline illustration */
.spline .poly { fill: none; stroke: #b9b2a8; stroke-width: 1.2; stroke-dasharray: 4 4; }
.spline .poly.moved { stroke: var(--accent); opacity: .45; }
.spline .curve { fill: none; stroke: var(--ink); stroke-width: 3; stroke-linecap: round; }
.spline .curve.ghost { stroke: #cfc8bd; stroke-width: 2.2; }
.spline .cp circle { fill: #fff; stroke: var(--ink-2); stroke-width: 1.6; }
.spline .cp-ghost { fill: none; stroke: #b9b2a8; stroke-width: 1.4; stroke-dasharray: 2 2; }
.spline .cp-hot { fill: var(--accent); stroke: #fff; stroke-width: 2; }
.spline .nudge { stroke: var(--accent); stroke-width: 1.4; color: var(--accent); }
.spline .note { font: italic 400 14px var(--serif); fill: var(--accent); text-anchor: middle; }

/* ---------- publications ---------- */
.pubgroup { font: 600 12.5px/1.4 var(--sans); letter-spacing: .1em; text-transform: uppercase; color: var(--muted); margin: 2.8em 0 1em; display: flex; align-items: center; gap: 10px; }
.pubgroup .count { font-weight: 500; letter-spacing: 0; background: var(--band); color: var(--ink-2); border-radius: 999px; padding: 0 9px; }
.pub-list { display: grid; grid-template-columns: minmax(0, 1fr); gap: 14px; max-width: 1000px; }
.pub {
  background: #fff; border: 1px solid var(--rule); border-radius: 14px; padding: 18px 22px 16px;
  transition: border-color .15s, box-shadow .15s;
}
.pub:hover { border-color: #d6cfc4; box-shadow: 0 8px 24px -16px rgba(60, 40, 30, .25); }
.pub.has-fig { display: grid; grid-template-columns: 330px minmax(0, 1fr); gap: 24px; align-items: start; }
.pub-figs { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }
.pub-fig { margin: 0; min-width: 0; }
.fig-btn {
  display: block; width: 100%; aspect-ratio: 4 / 3; padding: 6px; cursor: zoom-in;
  border: 1px solid var(--rule); border-radius: 10px; background: #fff; transition: border-color .15s;
}
.fig-btn:hover, .fig-btn:focus-visible { border-color: var(--accent); outline: none; }
.fig-btn img { width: 100%; height: 100%; object-fit: contain; display: block; }
.fig-credit { grid-column: 1 / -1; margin: 0; font-size: 11px; line-height: 1.4; color: var(--muted); }
.pub-fig figcaption {
  margin-top: 5px; text-align: center; font-size: 11px; font-weight: 600;
  letter-spacing: .08em; text-transform: uppercase; color: var(--muted);
}

/* ---------- figure viewer ---------- */
.lightbox {
  border: 0; border-radius: 14px; padding: 18px 18px 14px; background: #fff;
  width: min(1180px, 94vw); max-height: 92vh; box-shadow: 0 24px 60px -20px rgba(0,0,0,.45);
}
.lightbox::backdrop { background: rgba(24, 20, 18, .72); }
.lightbox figure { margin: 0; }
.lightbox img { display: block; margin: 0 auto; max-width: 100%; max-height: calc(92vh - 96px); object-fit: contain; }
.lightbox figcaption { margin-top: 10px; padding-right: 40px; font-size: 14px; color: var(--ink-2); }
.lb-close {
  position: absolute; top: 10px; right: 10px; width: 34px; height: 34px; border-radius: 50%;
  border: 1px solid var(--rule); background: #fff; color: var(--ink); font-size: 20px; line-height: 1; cursor: pointer;
}
.lb-close:hover { border-color: var(--accent); color: var(--accent); }
.pub-text { min-width: 0; }
.pub-title { font: 500 19px/1.35 var(--serif); margin: 0 0 6px; color: var(--ink); }
.pub-authors { margin: 0; font-size: 14.5px; color: var(--ink-2); }
.pub-venue { margin: 2px 0 12px; font-size: 14.5px; color: var(--muted); }
.pub-venue em { color: var(--ink-2); }
.me { font-weight: 600; color: var(--ink); }
.tag {
  display: inline-block; font-size: 11.5px; font-weight: 500; letter-spacing: .02em;
  padding: 1px 8px; border-radius: 999px; background: var(--accent-soft); color: var(--accent); margin-left: 4px;
}
.pub-links { display: flex; flex-wrap: wrap; align-items: flex-start; gap: 8px; }
.pill, .pub-more > summary {
  display: inline-flex; align-items: center; gap: 6px; height: 30px; padding: 0 13px; border-radius: 999px;
  border: 1px solid var(--rule); background: var(--paper); color: var(--ink); font-size: 13.5px; font-weight: 500;
  cursor: pointer; user-select: none;
}
.pill:hover, .pub-more > summary:hover { border-color: var(--accent); color: var(--accent); }
.pill.code svg { width: 14px; height: 14px; }
.pub-more { flex-basis: 100%; order: 10; margin-top: 2px; }
.pub-links > .pub-more { flex-basis: auto; order: 0; }
.pub-more > summary { list-style: none; }
.pub-more > summary::-webkit-details-marker { display: none; }
.pub-more > summary::after { content: "+"; font-size: 15px; line-height: 1; color: var(--muted); }
.pub-more[open] > summary { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }
.pub-more[open] > summary::after { content: "−"; color: var(--accent); }
.pub-more[open] { flex-basis: 100%; }
.pub, .pub-more, .pub-body, .bib { min-width: 0; max-width: 100%; }
.pub-body { margin-top: 14px; padding-top: 14px; border-top: 1px dashed var(--rule); }
.pub-body p { margin: 0 0 10px; color: var(--ink-2); font-size: 15px; }
.hl { margin: 0 0 12px; padding-left: 1.2em; }
.hl li { color: var(--ink-2); font-size: 14.5px; padding: 2px 0; }
.hl li::marker { color: var(--accent); }
.pub-thumb { max-width: 520px; width: 100%; border-radius: 10px; border: 1px solid var(--rule); margin: 4px 0 12px; }
.bib { border: 1px solid var(--rule); border-radius: 10px; overflow: hidden; }
.bib-head { display: flex; justify-content: space-between; align-items: center; padding: 6px 12px; background: var(--band); font-size: 12px; font-weight: 600; letter-spacing: .06em; text-transform: uppercase; color: var(--muted); }
.copy { font: 500 12px var(--sans); border: 1px solid var(--rule); background: #fff; border-radius: 6px; padding: 2px 10px; cursor: pointer; color: var(--ink-2); text-transform: none; letter-spacing: 0; }
.copy:hover { border-color: var(--accent); color: var(--accent); }
.bib pre { margin: 0; padding: 12px 14px; font: 12.5px/1.5 ui-monospace, "SF Mono", Consolas, monospace; color: var(--ink-2); overflow-x: auto; background: #fff; }

/* ---------- teaching ---------- */
.two-col { display: grid; grid-template-columns: 1.2fr 1fr; gap: 64px; }
.two-col p { color: var(--ink-2); }
.plain { list-style: none; padding: 0; margin: 0; }
.plain li { padding: 6px 0; border-bottom: 1px solid var(--rule); color: var(--ink-2); font-size: 15.5px; }
.chips { list-style: none; padding: 0; margin: 0; display: flex; flex-wrap: wrap; gap: 8px; }
.chips li { font-size: 14px; padding: 5px 12px; border-radius: 999px; background: #fff; border: 1px solid var(--rule); color: var(--ink-2); }

/* ---------- news ---------- */
.news { list-style: none; padding: 0; margin: 0; max-width: 820px; }
.news li { display: grid; grid-template-columns: 110px 1fr; gap: 20px; padding: 14px 0; border-bottom: 1px solid var(--rule); color: var(--ink-2); }
.when { font: 500 15px var(--serif); color: var(--accent); }

/* ---------- footer ---------- */
.footer { border-top: 1px solid var(--rule); padding: 36px 0 48px; font-size: 14px; color: var(--muted); }
.footer p { margin: .3em 0; }
.credit { font-size: 12.5px; }

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .pub.has-fig { grid-template-columns: 1fr; gap: 16px; }
  .pub-figs { max-width: 520px; }
  nav { gap: 16px; }
  nav a:not(:last-child):nth-child(n+3) { display: none; }
  .hero, .thread, .two-col { grid-template-columns: 1fr; gap: 32px; }
  .hero { padding-top: 40px; }
  .hero-card { max-width: 560px; }
  .thread.reverse .thread-text { order: 0; }
  h2 { font-size: 30px; }
  .news li { grid-template-columns: 1fr; gap: 2px; }
}
@media (max-width: 480px) {
  .wrap { padding: 0 18px; }
  body { font-size: 16px; }
  .lede { font-size: 20px; }
}