/* ============================================================
   Zhifeng Cai — academic site
   Palette: ink black, seal red, muted gold on rice paper
   ============================================================ */

:root {
  --ink: #1c1a17;
  --ink-soft: #3a3732;
  --rice: #f7f2e7;
  --rice-soft: #efe8d6;
  --seal: #a93c2f;
  --seal-dark: #7e2c22;
  --gold: #b38b4a;
  --rule: #d8cfb8;
  --link: #7e2c22;
  --link-hover: #a93c2f;
  --max: 780px;
}

* { box-sizing: border-box; }

html { -webkit-font-smoothing: antialiased; }

body {
  margin: 0;
  padding: 0;
  background: var(--rice);
  color: var(--ink);
  font-family: "Source Serif 4", "Source Serif Pro", "Noto Serif SC", Georgia, "Songti SC", serif;
  font-size: 18.5px;
  line-height: 1.68;
}

/* Subtle rice-paper texture via gradient noise */
body::before {
  content: "";
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: -1;
  background-image:
    radial-gradient(circle at 20% 30%, rgba(179, 139, 74, 0.04), transparent 40%),
    radial-gradient(circle at 80% 70%, rgba(169, 60, 47, 0.03), transparent 45%);
}

a {
  color: var(--link);
  text-decoration: none;
  border-bottom: 1px solid rgba(169, 60, 47, 0.3);
  transition: color 0.15s, border-color 0.15s;
}
a:hover {
  color: var(--link-hover);
  border-bottom-color: var(--link-hover);
}

/* ============ Layout ============ */

.wrap {
  max-width: var(--max);
  margin: 0 auto;
  padding: 2.5rem 1.5rem 4rem;
}

/* ============ Header / banner ============ */

header.site {
  border-bottom: 1px solid var(--rule);
  padding-bottom: 1.8rem;
  margin-bottom: 2.5rem;
  display: flex;
  align-items: baseline;
  gap: 1.25rem;
  flex-wrap: wrap;
}

.brand {
  font-family: "EB Garamond", "Noto Serif SC", Georgia, serif;
  font-size: 1.7rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  color: var(--ink);
  border: none;
}
.brand .cn {
  font-family: "Noto Serif SC", "Songti SC", "STSong", serif;
  font-size: 0.95em;
  color: var(--seal);
  margin-left: 0.45em;
  letter-spacing: 0.08em;
}

nav.site {
  margin-left: auto;
  display: flex;
  gap: 1.4rem;
  font-family: "EB Garamond", "Noto Serif SC", Georgia, serif;
  font-size: 1.02rem;
}
nav.site a {
  border: none;
  color: var(--ink-soft);
  letter-spacing: 0.02em;
}
nav.site a:hover { color: var(--seal); }
nav.site a.active { color: var(--seal); border-bottom: 1px solid var(--seal); padding-bottom: 2px; }

/* ============ Headings ============ */

h1, h2, h3 {
  font-family: "EB Garamond", "Noto Serif SC", Georgia, serif;
  font-weight: 500;
  color: var(--ink);
  letter-spacing: 0.01em;
}
h1 { font-size: 1.9rem; margin: 1.2rem 0 0.4rem; }
h2 {
  font-size: 1.35rem;
  margin: 2.6rem 0 1rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--rule);
  position: relative;
}
h2::before {
  content: "";
  display: inline-block;
  width: 6px;
  height: 1.05em;
  background: var(--seal);
  margin-right: 0.6em;
  vertical-align: -0.15em;
  border-radius: 1px;
}
h3 { font-size: 1.1rem; margin: 1.4rem 0 0.4rem; color: var(--ink); }

/* ============ Home bio block ============ */

.bio {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 1.8rem;
  align-items: start;
}
.bio.bio-noportrait {
  display: block;
}
.bio .portrait {
  width: 150px;
  height: 150px;
  border-radius: 4px;
  background: var(--rice-soft);
  border: 1px solid var(--rule);
  object-fit: cover;
  display: block;
}
.bio .portrait.placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: "Noto Serif SC", "Songti SC", serif;
  font-size: 3.2rem;
  color: var(--seal);
  background: var(--rice-soft);
}

.bio .lede p { margin: 0 0 0.7rem; }
.bio .affil {
  color: var(--ink-soft);
  font-style: italic;
  margin-top: 0.2rem;
}

/* ============ Publication list ============ */

.pubs { margin: 0.5rem 0 0; padding: 0; list-style: none; }
.pub {
  padding: 1rem 0 1rem;
  border-bottom: 1px dotted var(--rule);
}
.pub:last-child { border-bottom: none; }
.pub .title { font-weight: 500; color: var(--ink); }
.pub .authors { color: var(--ink-soft); }
.pub .venue { font-style: italic; color: var(--ink-soft); }
.pub .status {
  display: inline-block;
  font-size: 0.78rem;
  font-family: "EB Garamond", Georgia, serif;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--seal);
  border: 1px solid var(--seal);
  padding: 0.05rem 0.5rem;
  border-radius: 2px;
  margin-left: 0.4rem;
  vertical-align: 0.1em;
}
.pub .links { margin-top: 0.3rem; font-size: 0.92rem; }
.pub .links a { margin-right: 0.9rem; }
/* Hover abstract: inline trigger + floating popover */
.pub .abs {
  position: relative;
  display: inline-block;
  cursor: help;
  font-style: italic;
  color: var(--ink-soft);
  border-bottom: 1px dotted rgba(58, 55, 50, 0.4);
  margin-right: 0.9rem;
}
.pub .abs:hover,
.pub .abs:focus-within {
  color: var(--seal);
  border-bottom-color: var(--seal);
}
.pub .abs .abs-pop {
  position: absolute;
  left: 0;
  top: calc(100% + 0.5rem);
  z-index: 20;
  width: min(30rem, 85vw);
  padding: 0.85rem 1rem;
  background: #fcfaf1;
  border: 1px solid var(--rule);
  border-left: 2px solid var(--seal);
  box-shadow: 0 6px 20px -8px rgba(28, 26, 23, 0.25);
  color: var(--ink-soft);
  font-size: 0.94rem;
  font-style: normal;
  line-height: 1.55;
  opacity: 0;
  visibility: hidden;
  transform: translateY(-4px);
  transition: opacity 0.15s ease, transform 0.15s ease, visibility 0.15s;
  pointer-events: none;
  cursor: default;
}
.pub .abs:hover .abs-pop,
.pub .abs:focus-within .abs-pop {
  opacity: 1;
  visibility: visible;
  transform: translateY(0);
  pointer-events: auto;
}
@media (max-width: 640px) {
  .pub .abs .abs-pop { width: 88vw; left: 0; }
}

/* ============ Contact / footer ============ */

.contact-box {
  margin-top: 1.5rem;
  padding: 1rem 1.2rem;
  background: var(--rice-soft);
  border-left: 3px solid var(--seal);
  font-size: 0.97rem;
}
.contact-box p { margin: 0.2rem 0; }

footer.site {
  margin-top: 4rem;
  padding-top: 1.5rem;
  border-top: 1px solid var(--rule);
  color: var(--ink-soft);
  font-size: 0.85rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
}
footer.site .seal {
  font-family: "Noto Serif SC", "Songti SC", serif;
  color: white;
  background: var(--seal);
  padding: 0.35em 0.55em;
  font-size: 0.95rem;
  letter-spacing: 0.1em;
  border-radius: 2px;
}

/* ============ Responsive ============ */

@media (max-width: 640px) {
  .wrap { padding: 1.5rem 1rem 3rem; }
  header.site { flex-direction: column; gap: 0.6rem; align-items: flex-start; }
  nav.site { margin-left: 0; flex-wrap: wrap; gap: 1rem; }
  .bio { grid-template-columns: 1fr; }
  .bio .portrait { width: 120px; height: 120px; }
  h1 { font-size: 1.6rem; }
  h2 { font-size: 1.2rem; }
}