/* ===========================================================
   Tianjiao Li — personal site
   Minimal academic theme
   =========================================================== */

@import url('https://fonts.googleapis.com/css2?family=Source+Serif+4:ital,opsz,wght@0,8..60,400;0,8..60,500;0,8..60,600;1,8..60,400&family=Inter:wght@400;500;600&display=swap');

:root {
  --bg: #faf9f6;
  --bg-alt: #f2f0ea;
  --text: #232220;
  --text-muted: #5c5a55;
  --border: #e1ded4;
  --accent: #7a1f2b;       /* deep oxblood accent */
  --accent-soft: #7a1f2b1a;
  --serif: 'Source Serif 4', Georgia, 'Times New Roman', serif;
  --sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --max-width: 760px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #171614;
    --bg-alt: #1f1e1b;
    --text: #ece9e2;
    --text-muted: #a8a49a;
    --border: #34322c;
    --accent: #d98a92;
    --accent-soft: #d98a9224;
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--sans);
  font-size: 17px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

h1, h2 {
  font-family: var(--serif);
  font-weight: 600;
  line-height: 1.25;
  color: var(--text);
  margin: 0 0 0.5em;
}

h1 { font-size: 2.1rem; }
h2 { font-size: 1.9rem; color: var(--accent); margin-top: 2.6em; }

h3 {
  font-family: var(--sans);
  font-size: 1.2rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--accent);
  margin: 2.3em 0 1em;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border);
  scroll-margin-top: 84px;
}
h2 + h3 { margin-top: 1.6em; }

p { margin: 0 0 1em; }

a {
  color: var(--accent);
  text-decoration: none;
  border-bottom: 1px solid transparent;
}
a:hover { border-bottom-color: currentColor; }

.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- Header / nav ---------- */

header.site-header {
  border-bottom: 1px solid var(--border);
  background: var(--bg);
  position: sticky;
  top: 0;
  z-index: 10;
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 18px 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-name {
  font-family: var(--serif);
  font-weight: 600;
  font-size: 1.05rem;
  color: var(--text);
  border-bottom: none;
}
.site-name:hover { color: var(--accent); }

nav.primary-nav ul {
  list-style: none;
  display: flex;
  gap: 28px;
  margin: 0;
  padding: 0;
}

nav.primary-nav a {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 500;
  border-bottom: 2px solid transparent;
  padding-bottom: 3px;
}

nav.primary-nav a:hover,
nav.primary-nav a[aria-current="page"] {
  color: var(--text);
  border-bottom-color: var(--accent);
}

.nav-toggle {
  display: none;
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  width: 38px;
  height: 34px;
  cursor: pointer;
  color: var(--text);
}

@media (max-width: 620px) {
  nav.primary-nav {
    display: none;
    width: 100%;
    border-top: 1px solid var(--border);
    margin-top: 14px;
  }
  nav.primary-nav.open { display: block; }
  nav.primary-nav ul {
    flex-direction: column;
    gap: 0;
    padding-top: 6px;
  }
  nav.primary-nav li { padding: 10px 0; border-bottom: 1px solid var(--border); }
  nav.primary-nav li:last-child { border-bottom: none; }
  .nav-inner { flex-wrap: wrap; }
  .nav-toggle { display: block; }
}

/* ---------- Main / hero ---------- */

main { padding-bottom: 40px; }

main section.container {
  padding-top: 64px;
  scroll-margin-top: 84px;
}
main section.container:first-of-type {
  padding-top: 56px;
  scroll-margin-top: 0;
}
main section.container + section.container {
  border-top: 1px solid var(--border);
}

.section-title { margin-top: 0; }

.hero {
  display: flex;
  gap: 32px;
  align-items: center;
  margin-bottom: 8px;
}

.hero-photo {
  flex: 0 0 auto;
  width: 128px;
  height: 128px;
  border-radius: 50%;
  object-fit: cover;
  border: 1px solid var(--border);
  background: var(--bg-alt);
}

.hero-text .eyebrow {
  font-size: 0.85rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 8px;
}

.hero-text h1 { margin-bottom: 4px; }
.hero-text .role { color: var(--text-muted); font-size: 1.05rem; }

@media (max-width: 520px) {
  .hero { flex-direction: column; align-items: flex-start; text-align: left; }
}

.lede { font-size: 1.08rem; color: var(--text-muted); margin-top: 1.6em; }

.section-jump {
  display: flex;
  flex-wrap: wrap;
  gap: 6px 18px;
  margin: 0 0 0.5em;
  font-size: 0.88rem;
}
.section-jump a {
  color: var(--text-muted);
  border-bottom: 1px solid transparent;
}
.section-jump a:hover { color: var(--accent); border-bottom-color: currentColor; }

/* ---------- Cards / lists ---------- */

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

.pub { padding: 10px 0; }
.pub + .pub { margin-top: 6px; }

.pub-title { font-weight: 600; margin-bottom: 4px; }
.pub-meta { color: var(--text-muted); font-size: 0.94rem; }
.pub-tag {
  display: inline-block;
  font-size: 0.72rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 4px;
  padding: 2px 8px;
  margin-bottom: 8px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 16px;
  margin-top: 1.4em;
}

.card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 18px;
  background: var(--bg-alt);
}
.card h3 {
  font-family: var(--serif);
  font-size: 1.1rem;
  font-weight: 600;
  text-transform: none;
  letter-spacing: normal;
  color: var(--text);
  margin: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.placeholder {
  border: 1px dashed var(--border);
  border-radius: 8px;
  padding: 16px 18px;
  color: var(--text-muted);
  font-size: 0.95rem;
  background: var(--bg-alt);
}
.placeholder strong { color: var(--text); }

/* ---------- CV sections ---------- */

.cv-entry { margin-bottom: 1.2em; }
.cv-entry .when {
  float: right;
  color: var(--text-muted);
  font-size: 0.92rem;
}
.cv-entry .what { font-weight: 600; }
.cv-entry .where { color: var(--text-muted); font-size: 0.95rem; }

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

.contact-row {
  display: flex;
  align-items: baseline;
  gap: 10px;
  padding: 6px 0;
}
.contact-label {
  flex: 0 0 110px;
  color: var(--text-muted);
  font-size: 0.9rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

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

footer.site-footer {
  border-top: 1px solid var(--border);
  margin-top: 40px;
  padding: 24px 0 48px;
  color: var(--text-muted);
  font-size: 0.88rem;
}