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

:root {
  --bg: #ffffff;
  --text: #1a1a1a;
  --text-secondary: #555;
  --accent: #2c5f7c;
  --accent-light: #e8f0f5;
  --border: #ddd;
  --card-bg: #fff;
  --serif: 'Source Serif 4', Georgia, serif;
  --sans: 'DM Sans', system-ui, sans-serif;
  --max-w: 860px;
  --nav-h: 56px;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--sans);
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 15.5px;
  -webkit-font-smoothing: antialiased;
}

/* NAV */
nav {
  position: sticky; top: 0; z-index: 100;
  background: rgba(255,255,255,.92);
  backdrop-filter: blur(12px);
  height: var(--nav-h);
  display: flex; align-items: center; justify-content: center;
}
nav .inner {
  width: 100%; max-width: var(--max-w);
  padding: 0 28px;
  display: flex; align-items: center; justify-content: space-between;
}
nav .name {
  font-family: var(--serif);
  font-weight: 600; font-size: 18px;
  color: var(--text); text-decoration: none;
  letter-spacing: -.02em;
}
nav .links { display: flex; gap: 28px; }
nav .links a {
  font-size: 14px; font-weight: 500;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color .2s;
  position: relative;
}
nav .links a:hover, nav .links a.active { color: var(--accent); }
nav .links a.active::after {
  content: ''; position: absolute;
  bottom: -4px; left: 0; right: 0;
  height: 2px; background: var(--accent); border-radius: 1px;
}
.hamburger { display: none; background: none; border: none; cursor: pointer; padding: 4px; }
.hamburger svg { width: 22px; height: 22px; stroke: var(--text); }

/* MAIN */
main { max-width: var(--max-w); margin: 0 auto; padding: 56px 28px; }

/* HOME */
.home-grid {
  display: grid;
  grid-template-columns: 240px 1fr;
  gap: 48px;
  align-items: start;
}
.photo-wrap {
  border-radius: 6px;
  overflow: hidden;
  aspect-ratio: 3/4;
  background: linear-gradient(135deg, var(--accent-light) 0%, #d4dfe6 100%);
  position: relative;
}
.photo-wrap .placeholder-text {
  position: absolute; inset: 0;
  display: flex; align-items: center; justify-content: center;
  font-size: 13px; color: var(--accent); font-weight: 500; opacity: .7;
}
.bio h1 {
  font-family: var(--serif);
  font-size: 32px; font-weight: 700;
  letter-spacing: -.03em;
  margin-bottom: 20px;
  line-height: 1.15;
}
.bio p { margin-bottom: 14px; color: var(--text-secondary); }
.bio p a { color: var(--accent); text-decoration: none; border-bottom: 1px solid transparent; transition: border-color .2s; }
.bio p a:hover { border-bottom-color: var(--accent); }
.contact-line {
  margin-top: 24px;
  padding-top: 20px;
}
.contact-line a {
  color: var(--accent); text-decoration: none; font-weight: 500;
  font-size: 15px;
}
.social-links { margin-top: 12px; display: flex; gap: 16px; flex-wrap: wrap; }
.social-links a {
  font-size: 13px; color: var(--text-secondary);
  text-decoration: none; transition: color .2s;
}
.social-links a:hover { color: var(--accent); }

/* RESEARCH */
.section-title {
  font-family: var(--serif);
  font-size: 26px; font-weight: 600;
  letter-spacing: -.02em;
  margin-bottom: 36px;
}
.paper-category {
  font-size: 12px; font-weight: 600;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--accent);
  margin-bottom: 20px;
  margin-top: 36px;
}
.paper-category:first-of-type { margin-top: 0; }

.paper {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 28px;
  margin-bottom: 20px;
  display: grid;
  grid-template-columns: 1fr 280px;
  gap: 28px;
  align-items: start;
  transition: box-shadow .25s;
}
.paper:hover { box-shadow: 0 4px 20px rgba(0,0,0,.06); }

.paper-info h3 {
  font-family: var(--serif);
  font-size: 18px; font-weight: 600;
  line-height: 1.35;
  margin-bottom: 6px;
  letter-spacing: -.01em;
}
.paper-info h3 a { color: var(--text); text-decoration: none; transition: color .2s; }
.paper-info h3 a:hover { color: var(--accent); }
.paper-meta {
  font-size: 13.5px; color: var(--text-secondary);
  margin-bottom: 10px;
}
.paper-meta .coauthors { font-style: italic; }
.paper-meta .status {
  display: inline-block;
  background: var(--accent-light);
  color: var(--accent);
  font-size: 11.5px; font-weight: 600;
  padding: 2px 8px; border-radius: 3px;
  margin-left: 6px;
  font-style: normal;
}
.abstract-toggle {
  background: none; border: none;
  font-size: 13px; color: var(--accent);
  cursor: pointer; font-weight: 500;
  font-family: var(--sans);
  padding: 0; margin-top: 4px;
}
.abstract-toggle:hover { text-decoration: underline; }
.abstract-text {
  display: none; margin-top: 12px;
  font-size: 14px; color: var(--text-secondary);
  line-height: 1.7;
  border-left: 3px solid var(--accent-light);
  padding-left: 16px;
  text-align: justify;
}
.abstract-text.open { display: block; }

.paper-graph {
  width: 200px; height: 140px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 6px;
  overflow: hidden;
  flex-shrink: 0;
}
.paper-graph svg { width: 100%; height: 100%; }

/* CV */
.cv-note { color: var(--text-secondary); margin-bottom: 20px; font-size: 14.5px; }
.cv-embed {
  width: 100%; height: 700px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--card-bg);
}

/* FOOTER */
footer {
  max-width: var(--max-w); margin: 0 auto;
  padding: 28px;
  text-align: center;
  font-size: 12.5px; color: #aaa;
}

/* ANIMATION */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}
.animate { animation: fadeUp .5s ease both; }
.animate-d1 { animation-delay: .1s; }
.animate-d2 { animation-delay: .2s; }
.animate-d3 { animation-delay: .3s; }

/* RESPONSIVE */
@media (max-width: 700px) {
  .home-grid { grid-template-columns: 1fr; gap: 28px; }
  .photo-wrap { max-width: 200px; }
  .paper { grid-template-columns: 1fr; }
  .paper-graph { width: 100%; height: 120px; }
  nav .links { display: none; }
  nav .links.open {
    display: flex; flex-direction: column;
    position: absolute; top: var(--nav-h);
    left: 0; right: 0;
    background: rgba(255,255,255,.97);
    backdrop-filter: blur(12px);
    padding: 16px 28px; gap: 16px;
  }
  .hamburger { display: block; }
  .bio h1 { font-size: 26px; }
}