/* ==========================================================================
   Jing Lyu — Modern academic homepage
   Warm minimal aesthetic with editorial typography
   ========================================================================== */

:root {
  /* Core palette — warm, editorial */
  --bg: #faf8f5;          /* off-white cream */
  --bg-alt: #f3ede4;      /* slightly warmer panel */
  --surface: #ffffff;     /* card */
  --ink: #1a1814;         /* near-black, warm */
  --ink-soft: #4a4640;
  --ink-mute: #7c7670;
  --line: #e7ddd0;        /* warm divider */
  --line-strong: #d6c9b6;

  /* Accent — borrowed from the hero photo's warm fire-glow */
  --accent: #c14f1e;      /* burnt orange */
  --accent-soft: #e8a47a;
  --accent-bg: #fff1e7;
  --accent-deep: #8a3613;

  /* Cool secondary for contrast (deep night-sky blue) */
  --night: #1f2a44;
  --night-soft: #3d4a6b;

  --shadow-sm: 0 1px 3px rgba(40, 30, 20, 0.06);
  --shadow-md: 0 8px 24px rgba(40, 30, 20, 0.08);
  --shadow-lg: 0 16px 48px rgba(40, 30, 20, 0.12);

  --max: 1100px;
  --radius: 14px;
  --radius-sm: 8px;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--ink);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

a { color: var(--accent); text-decoration: none; transition: color 0.18s; }
a:hover { color: var(--accent-deep); }

img { display: block; max-width: 100%; }

h1, h2, h3, h4 {
  font-family: 'Inter', sans-serif;
  font-weight: 700;
  letter-spacing: -0.015em;
  color: var(--ink);
}

/* ==========================================================================
   TOP NAVIGATION
   ========================================================================== */
.topnav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  padding: 14px 0;
  background: transparent;
  transition: background 0.25s, box-shadow 0.25s, padding 0.25s;
}

.topnav.scrolled {
  background: rgba(250, 248, 245, 0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  box-shadow: 0 1px 0 var(--line);
  padding: 10px 0;
}

.topnav-inner {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 28px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand {
  font-weight: 800;
  font-size: 1.1em;
  letter-spacing: 0.05em;
  color: var(--ink);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px; height: 36px;
  border: 1.5px solid var(--ink);
  border-radius: 50%;
}
.brand:hover { background: var(--ink); color: var(--bg); }

.nav-links { display: flex; gap: 26px; }
.nav-links a {
  color: var(--ink-soft);
  font-size: 0.92em;
  font-weight: 500;
}
.nav-links a:hover { color: var(--accent); }

/* ==========================================================================
   HERO
   ========================================================================== */
.hero {
  position: relative;
  padding: 130px 28px 80px;
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 700px 400px at 85% 20%, rgba(193, 79, 30, 0.10), transparent 70%),
    radial-gradient(ellipse 600px 500px at 10% 80%, rgba(31, 42, 68, 0.06), transparent 70%),
    linear-gradient(180deg, var(--bg-alt) 0%, var(--bg) 100%);
  z-index: -1;
}

.hero-inner {
  max-width: var(--max);
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 320px;
  gap: 60px;
  align-items: center;
}

.hero-eyebrow {
  display: inline-block;
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.78em;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--accent);
  background: var(--accent-bg);
  padding: 6px 14px;
  border-radius: 999px;
  margin-bottom: 22px;
}

.hero h1 {
  font-size: clamp(2.4em, 5.5vw, 3.8em);
  line-height: 1.05;
  margin-bottom: 18px;
  letter-spacing: -0.03em;
}

.hero h1 .zh {
  font-family: 'Crimson Pro', 'STSong', serif;
  font-weight: 400;
  color: var(--ink-soft);
  font-size: 0.6em;
  font-style: italic;
  margin-left: 8px;
}

.hero-tagline {
  font-family: 'Crimson Pro', Georgia, serif;
  font-size: 1.25em;
  line-height: 1.55;
  color: var(--ink-soft);
  margin-bottom: 18px;
  max-width: 560px;
}

.hero-tagline b { color: var(--ink); font-weight: 600; }

.hero-affil {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--ink-mute);
  font-size: 0.95em;
  margin-bottom: 28px;
}
.hero-affil i { color: var(--accent); font-size: 1.15em; }

.hero-cta {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: 999px;
  font-size: 0.92em;
  font-weight: 500;
  transition: all 0.18s;
  cursor: pointer;
  border: 1.5px solid transparent;
}
.btn i { font-size: 1.1em; }

.btn-primary { background: var(--ink); color: var(--bg); }
.btn-primary:hover { background: var(--accent); color: white; transform: translateY(-1px); box-shadow: var(--shadow-md); }

.btn-outline { border-color: var(--ink); color: var(--ink); background: transparent; }
.btn-outline:hover { background: var(--ink); color: var(--bg); }

.btn-ghost { color: var(--ink-soft); background: transparent; }
.btn-ghost:hover { color: var(--accent); }

.hero-links {
  display: flex;
  gap: 14px;
  margin-top: 12px;
}
.hero-links a {
  width: 38px; height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--ink-soft);
  font-size: 1.25em;
  border: 1px solid var(--line);
  border-radius: 50%;
  background: var(--surface);
  transition: all 0.18s;
}
.hero-links a:hover {
  color: white;
  background: var(--accent);
  border-color: var(--accent);
  transform: translateY(-2px);
}

.hero-portrait {
  display: flex;
  justify-content: center;
}
.portrait-frame {
  position: relative;
  width: 280px; height: 280px;
  border-radius: 50%;
  overflow: hidden;
  box-shadow: var(--shadow-lg);
  border: 4px solid var(--surface);
}
.portrait-frame::before {
  content: '';
  position: absolute;
  inset: -10px;
  background: linear-gradient(135deg, var(--accent), var(--night));
  border-radius: 50%;
  z-index: -1;
  opacity: 0.18;
  filter: blur(20px);
}
.portrait-frame img {
  width: 100%; height: 100%;
  object-fit: cover;
}

/* ==========================================================================
   STATS BAR
   ========================================================================== */
.stats-bar {
  max-width: var(--max);
  margin: 0 auto;
  padding: 0 28px 60px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.stat {
  text-align: center;
  padding: 24px 16px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--line);
  transition: transform 0.2s, box-shadow 0.2s;
}
.stat:hover { transform: translateY(-3px); box-shadow: var(--shadow-md); border-color: var(--accent-soft); }

.stat-num {
  font-size: 2.4em;
  font-weight: 700;
  color: var(--accent);
  line-height: 1;
  letter-spacing: -0.03em;
  font-family: 'Inter', sans-serif;
}
.stat-plus { font-size: 0.7em; }

.stat-label {
  margin-top: 6px;
  font-size: 0.82em;
  color: var(--ink-mute);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  font-weight: 500;
}

/* ==========================================================================
   SECTIONS
   ========================================================================== */
.section {
  padding: 80px 28px;
}
.section-alt {
  background: var(--bg-alt);
}
.section-inner {
  max-width: var(--max);
  margin: 0 auto;
}

.section-head {
  display: flex;
  align-items: baseline;
  gap: 16px;
  margin-bottom: 18px;
}
.section-num {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.85em;
  color: var(--accent);
  font-weight: 500;
  letter-spacing: 0.05em;
}
.section-head h2 {
  font-size: 2.1em;
  letter-spacing: -0.025em;
}

.section-lede {
  font-family: 'Crimson Pro', Georgia, serif;
  font-size: 1.15em;
  color: var(--ink-soft);
  margin-bottom: 36px;
  max-width: 680px;
}

/* ==========================================================================
   ABOUT
   ========================================================================== */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 240px;
  gap: 50px;
}
.about-text p {
  margin-bottom: 16px;
  color: var(--ink-soft);
  font-size: 1.02em;
}
.about-text p b { color: var(--ink); font-weight: 600; }

.about-side {
  padding: 24px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--line);
  align-self: start;
}
.about-side h4 {
  font-size: 0.78em;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  color: var(--accent);
  margin-bottom: 14px;
}
.quick-facts {
  list-style: none;
}
.quick-facts li {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 0;
  font-size: 0.92em;
  color: var(--ink-soft);
  border-bottom: 1px dashed var(--line);
}
.quick-facts li:last-child { border-bottom: none; }
.quick-facts i { color: var(--accent); font-size: 1.1em; width: 18px; }

/* ==========================================================================
   RESEARCH CARDS
   ========================================================================== */
.research-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
}
.research-card {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 28px 24px;
  border: 1px solid var(--line);
  transition: all 0.25s;
}
.research-card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--accent-soft);
}

.research-icon {
  width: 48px; height: 48px;
  border-radius: 12px;
  background: var(--accent-bg);
  color: var(--accent);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 1.6em;
  margin-bottom: 18px;
}

.research-card h3 {
  font-size: 1.15em;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.research-card p {
  color: var(--ink-soft);
  font-size: 0.93em;
  line-height: 1.6;
  margin-bottom: 18px;
}

.research-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}
.research-tags span {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72em;
  padding: 3px 9px;
  background: var(--bg-alt);
  color: var(--ink-soft);
  border-radius: 999px;
  border: 1px solid var(--line);
}

/* ==========================================================================
   PUBLICATIONS
   ========================================================================== */
.pub-legend {
  font-size: 0.82em;
  color: var(--ink-mute);
  margin-bottom: 24px;
  font-family: 'JetBrains Mono', monospace;
}

.pub-list {
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.pub-item {
  display: grid;
  grid-template-columns: 200px 1fr;
  gap: 24px;
  padding: 22px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--line);
  transition: all 0.22s;
}

.pub-item:hover {
  border-color: var(--accent-soft);
  box-shadow: var(--shadow-md);
}

.pub-item.featured {
  border-color: var(--accent);
  background: linear-gradient(135deg, var(--surface) 0%, var(--accent-bg) 100%);
}

.pub-thumb {
  position: relative;
  border-radius: var(--radius-sm);
  overflow: hidden;
  background: var(--bg-alt);
  border: 1px solid var(--line);
  aspect-ratio: 4 / 3;
}
.pub-thumb img {
  width: 100%; height: 100%;
  object-fit: cover;
}

.pub-badge {
  position: absolute;
  top: 8px; left: 8px;
  background: var(--accent);
  color: white;
  font-size: 0.68em;
  font-weight: 600;
  padding: 3px 9px;
  border-radius: 999px;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.pub-venue-tag {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.76em;
  color: var(--accent);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 8px;
}

.pub-title {
  font-size: 1.08em;
  line-height: 1.35;
  margin-bottom: 10px;
  letter-spacing: -0.005em;
}
.pub-title a { color: var(--ink); }
.pub-title a:hover { color: var(--accent); }

.pub-authors {
  font-size: 0.9em;
  color: var(--ink-soft);
  margin-bottom: 12px;
}
.pub-authors b { color: var(--ink); font-weight: 600; }

.pub-actions {
  display: flex;
  gap: 14px;
}
.pub-actions a {
  font-size: 0.85em;
  color: var(--ink-mute);
  display: inline-flex;
  align-items: center;
  gap: 5px;
}
.pub-actions a:hover { color: var(--accent); }
.pub-actions i { font-size: 1.05em; }

/* ==========================================================================
   TIMELINE
   ========================================================================== */
.timeline {
  position: relative;
  padding-left: 28px;
}
.timeline::before {
  content: '';
  position: absolute;
  left: 8px; top: 8px; bottom: 8px;
  width: 2px;
  background: linear-gradient(180deg, var(--accent), var(--accent-soft), transparent);
}

.timeline-item {
  position: relative;
  padding-bottom: 32px;
}
.timeline-item:last-child { padding-bottom: 0; }

.timeline-marker {
  position: absolute;
  left: -25px; top: 6px;
  width: 14px; height: 14px;
  background: var(--accent);
  border: 3px solid var(--bg-alt);
  border-radius: 50%;
  box-shadow: 0 0 0 2px var(--accent-soft);
}

.timeline-date {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82em;
  color: var(--accent);
  font-weight: 500;
  margin-bottom: 6px;
}

.timeline-content h4 {
  font-size: 1.1em;
  margin-bottom: 4px;
}

.tl-org {
  font-size: 0.92em;
  color: var(--ink-soft);
  font-weight: 500;
  margin-bottom: 8px;
}

.timeline-content p {
  font-size: 0.93em;
  color: var(--ink-mute);
  line-height: 1.6;
}

/* ==========================================================================
   SKILLS & AWARDS
   ========================================================================== */
.skills-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 18px;
  margin-bottom: 48px;
}

.skills-card {
  padding: 22px 24px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--line);
}
.skills-card h4 {
  font-size: 0.95em;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}
.skills-card h4 i {
  color: var(--accent);
  font-size: 1.2em;
}

.skills-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 7px;
}
.skills-tags span {
  font-size: 0.82em;
  padding: 4px 11px;
  background: var(--bg-alt);
  color: var(--ink-soft);
  border-radius: 999px;
  border: 1px solid var(--line);
  font-weight: 500;
}

.awards-block {
  padding: 28px 32px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--line);
}
.awards-block h3 {
  font-size: 1.15em;
  margin-bottom: 18px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.awards-block h3 i { color: var(--accent); }

.awards-list {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 10px 30px;
}
.awards-list li {
  font-size: 0.92em;
  color: var(--ink-soft);
  padding: 6px 0;
  display: flex;
  gap: 12px;
  align-items: baseline;
  border-bottom: 1px dashed var(--line);
}
.award-year {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.82em;
  color: var(--accent);
  font-weight: 500;
  white-space: nowrap;
  min-width: 75px;
}

/* ==========================================================================
   NOTES / BLOG
   ========================================================================== */
.notes-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
}

.note-card {
  display: block;
  padding: 26px 28px;
  background: var(--surface);
  border-radius: var(--radius);
  border: 1px solid var(--line);
  color: var(--ink);
  transition: all 0.25s;
}
.note-card:hover:not(.note-placeholder) {
  transform: translateY(-3px);
  border-color: var(--accent-soft);
  box-shadow: var(--shadow-md);
  color: var(--ink);
}
.note-placeholder {
  opacity: 0.7;
}

.note-meta {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
}
.note-tag {
  font-family: 'JetBrains Mono', monospace;
  font-size: 0.72em;
  color: var(--accent);
  background: var(--accent-bg);
  padding: 3px 10px;
  border-radius: 999px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}
.note-date {
  font-size: 0.82em;
  color: var(--ink-mute);
  font-family: 'JetBrains Mono', monospace;
}

.note-card h3 {
  font-size: 1.15em;
  margin-bottom: 10px;
  line-height: 1.35;
}
.note-card p {
  color: var(--ink-soft);
  font-size: 0.92em;
  line-height: 1.6;
  margin-bottom: 14px;
}

.read-more {
  font-size: 0.88em;
  color: var(--accent);
  font-weight: 500;
  display: inline-flex;
  align-items: center;
  gap: 4px;
}
.read-more i { transition: transform 0.2s; }
.note-card:hover .read-more i { transform: translateX(3px); }

/* ==========================================================================
   CONTACT
   ========================================================================== */
.section-contact {
  background: linear-gradient(135deg, var(--night) 0%, #2a3654 100%);
  color: #f5ede2;
  padding: 80px 28px;
}

.contact-head {
  text-align: center;
  margin-bottom: 40px;
}
.contact-head .section-num { color: var(--accent-soft); }
.contact-head h2 {
  color: #fff;
  font-size: 2.2em;
  margin: 8px 0 16px;
  letter-spacing: -0.025em;
}
.contact-head p {
  font-family: 'Crimson Pro', Georgia, serif;
  font-size: 1.15em;
  color: rgba(245, 237, 226, 0.78);
  max-width: 620px;
  margin: 0 auto;
}

.contact-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  max-width: 720px;
  margin: 0 auto;
}

.contact-card {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 18px 22px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid rgba(255, 255, 255, 0.1);
  border-radius: var(--radius);
  color: #f5ede2;
  transition: all 0.2s;
}
.contact-card:hover {
  background: rgba(255, 255, 255, 0.12);
  border-color: var(--accent-soft);
  color: #fff;
  transform: translateY(-2px);
}

.contact-card > i {
  font-size: 1.8em;
  color: var(--accent-soft);
}
.cc-label {
  font-size: 0.78em;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: rgba(245, 237, 226, 0.6);
  margin-bottom: 2px;
}
.cc-value {
  font-size: 1em;
  font-weight: 500;
}

/* ==========================================================================
   FOOTER
   ========================================================================== */
.footer {
  background: var(--ink);
  color: rgba(250, 248, 245, 0.6);
  padding: 28px;
  font-size: 0.88em;
}
.footer-inner {
  max-width: var(--max);
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
}
.footer strong { color: rgba(250, 248, 245, 0.9); font-weight: 600; }
.footer-meta { font-size: 0.85em; }

/* ==========================================================================
   RESPONSIVE
   ========================================================================== */
@media (max-width: 880px) {
  .nav-links { display: none; }

  .hero { padding: 110px 24px 60px; }
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 30px;
    text-align: left;
  }
  .hero-portrait { order: -1; justify-content: flex-start; }
  .portrait-frame { width: 180px; height: 180px; }

  .stats-bar { grid-template-columns: repeat(2, 1fr); padding: 0 24px 50px; }

  .section { padding: 60px 24px; }
  .section-head h2 { font-size: 1.7em; }

  .about-grid { grid-template-columns: 1fr; gap: 28px; }
  .about-side { order: -1; }

  .research-grid { grid-template-columns: 1fr; gap: 14px; }

  .pub-item {
    grid-template-columns: 1fr;
    gap: 14px;
  }
  .pub-thumb { max-width: 240px; }

  .skills-grid { grid-template-columns: 1fr; }
  .awards-list { grid-template-columns: 1fr; gap: 8px; }

  .notes-grid { grid-template-columns: 1fr; }
  .contact-grid { grid-template-columns: 1fr; }

  .footer-inner { flex-direction: column; text-align: center; gap: 8px; }
}

@media (max-width: 480px) {
  .hero h1 { font-size: 2.2em; }
  .hero-tagline { font-size: 1.1em; }
  .hero-cta { flex-direction: column; align-items: stretch; }
  .btn { justify-content: center; }
}