/* ==========================================================================
   Xueqing Liu — personal academic site
   Warm scholarly minimal: off-white ground, serif display, one crimson accent
   ========================================================================== */

:root {
  --bg: #FBF9F5;
  --surface: #FFFFFF;
  --ink: #2B2723;
  --ink-soft: #5C554D;
  --ink-faint: #8A8177;
  --accent: #96222E;        /* deep scholarly crimson */
  --accent-dark: #6E1620;
  --accent-wash: #F6E9E8;
  --rule: #E8E1D6;
  --rule-soft: #F0EAE0;
  --serif: "Source Serif 4", Georgia, "Times New Roman", serif;
  --sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  --maxw: 52rem;
}

* { box-sizing: border-box; }

html {
  scroll-behavior: smooth;
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after { transition: none !important; animation: none !important; }
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--sans);
  font-size: 1.0625rem;           /* 17px */
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

/* ---- Accessibility helpers ---------------------------------------------- */

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: #fff;
  padding: 0.6rem 1rem;
  border-radius: 0 0 6px 0;
  z-index: 100;
}
.skip-link:focus {
  left: 0;
}

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

/* ---- Type --------------------------------------------------------------- */

h1, h2, h3 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.25;
  color: var(--ink);
  margin: 0;
}

h1 { font-size: 2.1rem; letter-spacing: -0.01em; }

.cn-name {
  font-family: "Kaiti SC", "STKaiti", "KaiTi", "TW-Kai", "AR PL KaitiM GB", serif;
  font-size: 0.66em;
  font-weight: 400;
  color: var(--ink-soft);
  margin-left: 0.2rem;
  white-space: nowrap;
}

h2 {
  font-size: 1.35rem;
  margin: 3rem 0 1.1rem;
  padding-bottom: 0.45rem;
  border-bottom: 1px solid var(--rule);
}

h3 { font-size: 1.1rem; margin: 1.6rem 0 0.5rem; }

p { margin: 0 0 1rem; }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
  transition: border-color 120ms ease, color 120ms ease;
}
a:hover {
  color: var(--accent-dark);
  border-bottom-color: currentColor;
}

::selection { background: var(--accent-wash); }

/* ---- Layout ------------------------------------------------------------- */

.wrap {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 1.25rem;
}

main {
  padding-bottom: 2rem;
}

/* ---- Site header / nav --------------------------------------------------- */

.site-header {
  border-bottom: 1px solid var(--rule);
  background: color-mix(in srgb, var(--bg) 92%, #fff);
}

.site-header .wrap {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.25rem 1.5rem;
  padding-top: 1.1rem;
  padding-bottom: 1.1rem;
}

.site-name {
  font-family: var(--serif);
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--ink);
  border-bottom: none;
}
.site-name:hover { color: var(--accent); }

.site-nav {
  display: flex;
  gap: 1.4rem;
  flex-wrap: wrap;
}

.site-nav a {
  font-size: 0.95rem;
  color: var(--ink-soft);
  border-bottom: 2px solid transparent;
  padding-bottom: 2px;
}
.site-nav a:hover { color: var(--accent-dark); border-bottom-color: var(--accent-dark); }
.site-nav a[aria-current="page"] {
  color: var(--accent);
  border-bottom-color: var(--accent);
  font-weight: 500;
}

/* ---- Hero ---------------------------------------------------------------- */

.hero {
  display: flex;
  gap: 2.2rem;
  align-items: center;
  padding: 3rem 0 0.5rem;
}

.hero-photo {
  flex: 0 0 auto;
  width: 168px;
  height: 168px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--surface);
  box-shadow: 0 1px 2px rgba(43, 39, 35, 0.12), 0 6px 18px rgba(43, 39, 35, 0.10);
}

.hero-title {
  font-size: 1.05rem;
  color: var(--ink-soft);
  margin: 0.4rem 0 0;
}
.hero-title .affil { color: var(--ink); }

.hero-loc {
  font-size: 0.92rem;
  color: var(--ink-faint);
  margin: 0.35rem 0 0;
}

/* Contact / profile links */
.profile-links {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin: 1.1rem 0 0;
  padding: 0;
  list-style: none;
}

.profile-links a {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.88rem;
  color: var(--ink-soft);
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: 0.32rem 0.85rem;
  transition: border-color 120ms ease, color 120ms ease, box-shadow 120ms ease;
}
.profile-links a:hover {
  color: var(--accent-dark);
  border-color: var(--accent);
  box-shadow: 0 1px 4px rgba(150, 34, 46, 0.12);
}
.profile-links svg {
  width: 15px;
  height: 15px;
  fill: currentColor;
  flex: 0 0 auto;
}

/* ---- Research interests --------------------------------------------------- */

.interests {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.9rem;
  margin: 0;
  padding: 0;
  list-style: none;
}

.interests li {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 0.9rem 1.1rem;
}

.interests strong {
  display: block;
  font-family: var(--serif);
  font-size: 1.02rem;
  font-weight: 600;
  margin-bottom: 0.2rem;
}

.interests span {
  font-size: 0.9rem;
  color: var(--ink-soft);
  line-height: 1.5;
}

/* ---- News ----------------------------------------------------------------- */

.news {
  margin: 0;
  padding: 0;
  list-style: none;
}

.news li {
  display: grid;
  grid-template-columns: 6.2rem 1fr;
  gap: 1.1rem;
  padding: 0.55rem 0;
  border-bottom: 1px solid var(--rule-soft);
}
.news li:last-child { border-bottom: none; }

.news time {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--accent);
  letter-spacing: 0.02em;
  padding-top: 0.15rem;
  white-space: nowrap;
}

.news .news-body { font-size: 0.97rem; }

/* ---- Publications ---------------------------------------------------------- */

.pub-list {
  margin: 0;
  padding: 0;
  list-style: none;
}

.pub {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 1.05rem 1.25rem;
  margin-bottom: 0.9rem;
}

.pub-title {
  font-family: var(--serif);
  font-size: 1.08rem;
  font-weight: 600;
  line-height: 1.4;
  margin: 0 0 0.35rem;
}

.pub-authors {
  font-size: 0.92rem;
  color: var(--ink-soft);
  margin: 0 0 0.45rem;
}
.pub-authors .me { color: var(--ink); font-weight: 600; }

.pub-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  margin: 0;
}

.pub-venue {
  font-size: 0.85rem;
  font-style: italic;
  color: var(--accent-dark);
  background: var(--accent-wash);
  border-radius: 999px;
  padding: 0.14rem 0.7rem;
}

.pub-links {
  display: inline-flex;
  gap: 0.4rem;
}

.pub-links a {
  font-size: 0.8rem;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--ink-soft);
  border: 1px solid var(--rule);
  border-radius: 999px;
  padding: 0.12rem 0.65rem;
  transition: border-color 120ms ease, color 120ms ease;
}
.pub-links a:hover { color: var(--accent-dark); border-color: var(--accent); }

.view-all {
  display: inline-block;
  margin-top: 0.4rem;
  font-size: 0.95rem;
  font-weight: 500;
}

.page-intro {
  color: var(--ink-soft);
  margin: 0 0 0.5rem;
}

.page-head {
  padding-top: 2.6rem;
}
.page-head h1 { font-size: 1.8rem; }

/* ---- Talks ----------------------------------------------------------------- */

.talk-year h2 { border-bottom: none; margin-bottom: 0.4rem; }

.talk-list {
  margin: 0 0 0.5rem;
  padding: 0;
  list-style: none;
  border-left: 2px solid var(--rule);
}

.talk-list li {
  position: relative;
  padding: 0.15rem 0 1.05rem 1.4rem;
}

.talk-list li::before {
  content: "";
  position: absolute;
  left: -6px;
  top: 0.62em;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--bg);
  border: 2px solid var(--accent);
}

.talk-title {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.03rem;
  margin: 0 0 0.15rem;
}

.talk-where {
  font-size: 0.92rem;
  color: var(--ink-soft);
  margin: 0;
}

.badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--accent-dark);
  background: var(--accent-wash);
  border-radius: 4px;
  padding: 0.1rem 0.45rem;
  margin-left: 0.5rem;
  vertical-align: 0.08em;
}
.badge.contributed {
  color: var(--ink-soft);
  background: var(--rule-soft);
}

/* ---- Contact block ---------------------------------------------------------- */

.contact-card {
  background: var(--surface);
  border: 1px solid var(--rule);
  border-radius: 10px;
  padding: 1.1rem 1.25rem;
  font-size: 0.97rem;
}
.contact-card p { margin: 0 0 0.35rem; }
.contact-card p:last-child { margin: 0; }

/* ---- Footer ------------------------------------------------------------------ */

.site-footer {
  margin-top: 3.5rem;
  border-top: 1px solid var(--rule);
  padding: 1.4rem 0 2rem;
  font-size: 0.85rem;
  color: var(--ink-faint);
}
.site-footer .wrap {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 0.5rem;
}
.site-footer a { color: var(--ink-soft); }

/* ---- Responsive --------------------------------------------------------------- */

@media (max-width: 640px) {
  body { font-size: 1rem; }

  .hero {
    flex-direction: column;
    align-items: flex-start;
    gap: 1.4rem;
    padding-top: 2.2rem;
  }

  .hero-photo { width: 132px; height: 132px; }

  h1 { font-size: 1.7rem; }

  .interests { grid-template-columns: 1fr; }

  .news li {
    grid-template-columns: 1fr;
    gap: 0.1rem;
  }
}