/* ============================================================
   Zhanyang Liu — personal site
   Clean, minimal academic style. Madison red accent (#c5050c).
   ============================================================ */

:root {
  --red: #c5050c;
  --red-dark: #9b0000;
  --ink: #1d1d1f;
  --body: #33333a;
  --muted: #6b6b73;
  --faint: #8a8a92;
  --rule: #e7e7e4;
  --rule-soft: #f0f0ee;
  --bg: #ffffff;
  --max: 720px;
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

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

body {
  margin: 0;
  background: var(--bg);
  color: var(--body);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.72;
  font-weight: 400;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  border-top: 4px solid var(--red);
}

/* Skip link */
.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--red);
  color: #fff;
  padding: .5rem .9rem;
  z-index: 100;
  border-radius: 0 0 4px 0;
}
.skip-link:focus { left: 0; }

a { color: var(--red); text-decoration: none; }
a:hover { color: var(--red-dark); text-decoration: underline; text-underline-offset: 2px; }

/* ---------- Header band ---------- */
.site-header {
  border-bottom: 1px solid var(--rule);
  background: #fff;
}
.header-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 2.6rem 1.4rem 2.2rem;
  display: flex;
  align-items: center;
  gap: 1.8rem;
}
.avatar {
  width: 132px;
  height: 132px;
  border-radius: 50%;
  object-fit: cover;
  flex-shrink: 0;
  box-shadow: 0 0 0 1px var(--rule);
}
.identity { min-width: 0; }
.identity h1 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 2.15rem;
  line-height: 1.15;
  letter-spacing: -0.01em;
  color: var(--ink);
  margin: 0 0 .35rem;
}
.identity .role {
  font-size: 1.02rem;
  color: var(--body);
  margin: 0 0 .1rem;
}
.identity .affil {
  font-size: 1.02rem;
  color: var(--muted);
  margin: 0 0 .85rem;
}
.contact-links {
  display: flex;
  flex-wrap: wrap;
  gap: .35rem 1.1rem;
  font-size: .93rem;
  margin: 0;
  padding: 0;
  list-style: none;
}
.contact-links a {
  color: var(--muted);
  border-bottom: 1px solid transparent;
}
.contact-links a:hover {
  color: var(--red);
  text-decoration: none;
  border-bottom-color: var(--red);
}

/* ---------- Navigation ---------- */
.site-nav {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(255,255,255,0.94);
  backdrop-filter: saturate(180%) blur(6px);
  border-bottom: 1px solid var(--rule);
}
.nav-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 1.4rem;
  display: flex;
  flex-wrap: wrap;
  gap: .2rem 1.6rem;
}
.site-nav a {
  display: inline-block;
  padding: .85rem 0;
  color: var(--muted);
  font-size: .95rem;
  font-weight: 500;
  letter-spacing: .01em;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
}
.site-nav a:hover {
  color: var(--red);
  text-decoration: none;
}
.site-nav a[aria-current="page"] {
  color: var(--ink);
  border-bottom-color: var(--red);
}

/* ---------- Main ---------- */
main {
  max-width: var(--max);
  margin: 0 auto;
  padding: 2.8rem 1.4rem 1rem;
}

.lead {
  font-size: 1.24rem;
  line-height: 1.6;
  color: var(--ink);
  font-family: var(--serif);
  font-weight: 400;
  margin: 0 0 2rem;
}
.lead .accent { color: var(--red); }

p { margin: 0 0 1.15rem; }

section { margin-bottom: 2.8rem; }

h2.section-title {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.4rem;
  color: var(--ink);
  margin: 0 0 1.2rem;
  padding-bottom: .5rem;
  border-bottom: 1px solid var(--rule);
  position: relative;
}
h2.section-title::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -1px;
  width: 44px;
  height: 3px;
  background: var(--red);
}

.page-note {
  color: var(--muted);
  font-size: .95rem;
  font-style: italic;
  margin: -0.6rem 0 1.8rem;
}

/* ---------- Definition-style rows (education / awards) ---------- */
.entry-list { margin: 0; padding: 0; list-style: none; }
.entry {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  gap: 1.5rem;
  padding: .85rem 0;
  border-bottom: 1px solid var(--rule-soft);
}
.entry:last-child { border-bottom: none; }
.entry .entry-main { min-width: 0; }
.entry .entry-title {
  color: var(--ink);
  font-weight: 600;
  margin: 0 0 .1rem;
}
.entry .entry-sub {
  color: var(--muted);
  font-size: .96rem;
  margin: 0;
}
.entry .entry-meta {
  color: var(--faint);
  font-size: .9rem;
  white-space: nowrap;
  flex-shrink: 0;
  text-align: right;
}

/* ---------- Research / project blocks ---------- */
.work { padding: 1.4rem 0; border-top: 1px solid var(--rule-soft); }
.work:first-of-type { border-top: none; padding-top: .2rem; }
.work h3 {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.22rem;
  line-height: 1.35;
  color: var(--ink);
  margin: 0 0 .5rem;
}
.work h3 a { color: var(--ink); }
.work h3 a:hover { color: var(--red); }
.status {
  display: inline-block;
  font-size: .72rem;
  font-weight: 600;
  letter-spacing: .06em;
  text-transform: uppercase;
  color: var(--red);
  vertical-align: middle;
  margin-left: .5rem;
}
.status.muted { color: var(--faint); }
.work p { margin: 0 0 .7rem; color: var(--body); }
.meta-line {
  font-size: .88rem;
  color: var(--faint);
  margin: 0;
}
.work-links {
  margin: .55rem 0 0;
  font-size: .92rem;
  display: flex;
  gap: 1.2rem;
  flex-wrap: wrap;
}
.work-links a { font-weight: 500; }

/* ---------- Publications ---------- */
.pub { padding: 1.2rem 0; border-top: 1px solid var(--rule-soft); }
.pub:first-of-type { border-top: none; padding-top: .2rem; }
.pub .pub-title { color: var(--ink); font-weight: 600; margin: 0 0 .25rem; }
.pub .pub-cite { color: var(--muted); font-size: .96rem; margin: 0; }
.pub .pub-cite em { color: var(--body); }

/* ---------- Updates ---------- */
.updates { margin: 0; padding: 0; list-style: none; }
.update {
  display: flex;
  gap: 1.4rem;
  padding: 1rem 0;
  border-bottom: 1px solid var(--rule-soft);
}
.update:last-child { border-bottom: none; }
.update .u-date {
  flex: 0 0 6.2rem;
  color: var(--red);
  font-weight: 600;
  font-size: .9rem;
  letter-spacing: .02em;
  padding-top: .12rem;
}
.update .u-text { margin: 0; color: var(--body); }

/* ---------- Skills / grouped text ---------- */
.skill-row {
  display: flex;
  gap: 1rem;
  padding: .55rem 0;
  border-bottom: 1px solid var(--rule-soft);
  font-size: .98rem;
}
.skill-row:last-child { border-bottom: none; }
.skill-row .k {
  flex: 0 0 9.5rem;
  color: var(--ink);
  font-weight: 600;
}
.skill-row .v { color: var(--body); margin: 0; }

/* ---------- Footer ---------- */
.site-footer {
  max-width: var(--max);
  margin: 2rem auto 0;
  padding: 1.8rem 1.4rem 3rem;
  border-top: 1px solid var(--rule);
  color: var(--faint);
  font-size: .88rem;
  text-align: center;
}
.site-footer a { color: var(--muted); }

/* ---------- CV viewer ---------- */
.cv-actions {
  display: flex;
  align-items: center;
  gap: 1.3rem;
  margin: -0.4rem 0 1.4rem;
  font-size: .95rem;
}
.btn {
  display: inline-block;
  background: var(--red);
  color: #fff;
  padding: .5rem 1rem;
  border-radius: 4px;
  font-weight: 500;
}
.btn:hover { background: var(--red-dark); color: #fff; text-decoration: none; }
.pdf-wrap {
  border: 1px solid var(--rule);
  border-radius: 6px;
  overflow: hidden;
  background: #f7f7f5;
}
.pdf-frame {
  width: 100%;
  height: 88vh;
  border: 0;
  display: block;
}

/* ---------- Responsive ---------- */
@media (max-width: 620px) {
  body { font-size: 16px; }
  .header-inner {
    flex-direction: column;
    text-align: center;
    gap: 1.1rem;
    padding: 2.1rem 1.2rem 1.7rem;
  }
  .contact-links { justify-content: center; }
  .identity h1 { font-size: 1.9rem; }
  .nav-inner { gap: .1rem 1.15rem; justify-content: center; }
  .entry { flex-direction: column; gap: .25rem; }
  .entry .entry-meta { text-align: left; }
  .update { flex-direction: column; gap: .2rem; }
  .update .u-date { flex-basis: auto; }
  .skill-row { flex-direction: column; gap: .1rem; }
  .skill-row .k { flex-basis: auto; }
  .pdf-frame { height: 70vh; }
}