:root {
  --bg: #ffffff;
  --bg-alt: #f6f7f9;
  --text: #1a1d23;
  --text-muted: #5a6070;
  --accent: #2f5fd0;
  --accent-contrast: #ffffff;
  --border: #e4e6eb;
  --card-bg: #ffffff;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 1px 3px rgba(16, 24, 40, 0.06);
  --radius: 12px;
  --max-width: 960px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #14161a;
    --bg-alt: #1b1e24;
    --text: #edeef1;
    --text-muted: #9aa1af;
    --accent: #6f95ef;
    --accent-contrast: #0e1116;
    --border: #2a2e37;
    --card-bg: #1b1e24;
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 1px 3px rgba(0, 0, 0, 0.4);
  }
}

:root[data-theme="dark"] {
  --bg: #14161a;
  --bg-alt: #1b1e24;
  --text: #edeef1;
  --text-muted: #9aa1af;
  --accent: #6f95ef;
  --accent-contrast: #0e1116;
  --border: #2a2e37;
  --card-bg: #1b1e24;
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 1px 3px rgba(0, 0, 0, 0.4);
}

:root[data-theme="light"] {
  --bg: #ffffff;
  --bg-alt: #f6f7f9;
  --text: #1a1d23;
  --text-muted: #5a6070;
  --accent: #2f5fd0;
  --accent-contrast: #ffffff;
  --border: #e4e6eb;
  --card-bg: #ffffff;
  --shadow: 0 1px 2px rgba(16, 24, 40, 0.04), 0 1px 3px rgba(16, 24, 40, 0.06);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  overflow-x: hidden;
}

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

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

a { color: var(--accent); }

/* Header */
.site-header {
  position: sticky;
  top: 0;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
}

.brand {
  font-weight: 700;
  text-decoration: none;
  color: var(--text);
  font-size: 1.05rem;
}

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

.nav-links a {
  text-decoration: none;
  color: var(--text-muted);
  font-size: 0.95rem;
  transition: color 0.15s ease;
}

.nav-links a:hover { color: var(--accent); }

.nav-toggle {
  display: none;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 6px;
}

.nav-toggle span {
  width: 22px;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
}

/* Hero */
.hero {
  display: flex;
  align-items: center;
  gap: 48px;
  padding: 72px 24px 56px;
  flex-wrap: wrap;
}

.hero-photo img {
  width: 180px;
  height: 180px;
  border-radius: 50%;
  object-fit: cover;
  box-shadow: var(--shadow);
  border: 3px solid var(--card-bg);
}

.hero-text { flex: 1; min-width: 280px; }

.eyebrow {
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-size: 0.8rem;
  color: var(--accent);
  font-weight: 600;
  margin: 0 0 8px;
}

.hero h1 {
  font-size: clamp(2rem, 4vw, 2.75rem);
  margin: 0 0 16px;
  letter-spacing: -0.02em;
}

.lede {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 60ch;
  margin: 0 0 28px;
}

.hero-actions { display: flex; gap: 12px; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 11px 22px;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: transform 0.15s ease, opacity 0.15s ease;
  border: 1px solid transparent;
}

.btn:hover { transform: translateY(-1px); }

.btn-primary {
  background: var(--accent);
  color: var(--accent-contrast);
}

.btn-outline {
  background: transparent;
  color: var(--text);
  border-color: var(--border);
}

/* Sections */
.section { padding: 56px 24px; border-top: 1px solid var(--border); }

.section h2 {
  font-size: 1.6rem;
  margin: 0 0 32px;
  letter-spacing: -0.01em;
}

.sub-heading { font-size: 1.1rem; margin: 40px 0 16px; }

.patent-heading {
  font-size: 1.6rem;
  letter-spacing: -0.01em;
  margin: 56px 0 32px;
  padding-top: 40px;
  border-top: 1px solid var(--border);
}

.about-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 48px;
}

.about-grid h3 { font-size: 1.05rem; margin: 0 0 20px; }

/* Timeline */
.timeline {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.timeline li {
  display: grid;
  grid-template-columns: 150px 1fr;
  gap: 16px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}

.timeline li:last-child { border-bottom: none; padding-bottom: 0; }

.timeline-date {
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  white-space: nowrap;
}

.timeline strong { display: block; margin-bottom: 4px; font-size: 1.02rem; }

.timeline p { margin: 4px 0 0; color: var(--text-muted); font-size: 0.94rem; }

/* Tags */
.tag-group { margin-bottom: 24px; }

.tag-group h4 {
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--text-muted);
  margin: 0 0 10px;
}

.tags { display: flex; flex-wrap: wrap; gap: 8px; }

.tag {
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 5px 13px;
  font-size: 0.83rem;
  color: var(--text);
}

/* Cards */
.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 20px;
}

.card {
  background: var(--card-bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 22px;
  box-shadow: var(--shadow);
}

.card-tag {
  font-size: 0.78rem;
  color: var(--accent);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
}

.card h3 { font-size: 1.05rem; margin: 10px 0 8px; }

.card p { margin: 0; color: var(--text-muted); font-size: 0.92rem; }

/* Publications */
.pub-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 22px; }

.pub-list li {
  display: grid;
  grid-template-columns: 60px 1fr;
  gap: 16px;
  padding-bottom: 22px;
  border-bottom: 1px solid var(--border);
}

.pub-list li:last-child { border-bottom: none; }

.pub-year { color: var(--text-muted); font-weight: 700; font-size: 0.9rem; }

.pub-list p { margin: 0 0 8px; font-size: 0.94rem; }

.pub-type {
  display: inline-block;
  background: var(--bg-alt);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 3px 11px;
  font-size: 0.76rem;
  color: var(--text-muted);
}

.pub-videos {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  margin: 4px 0 12px;
}

.pub-video {
  width: 280px;
  max-width: 100%;
}

.pub-video-label {
  display: block;
  font-size: 0.78rem;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.pub-video-frame {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: var(--bg-alt);
}

.pub-video-frame iframe {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border: 0;
}

/* Plain lists */
.plain-list { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 14px; }

.plain-list li {
  font-size: 0.92rem;
  color: var(--text-muted);
  padding-bottom: 14px;
  border-bottom: 1px solid var(--border);
}

.plain-list li:last-child { border-bottom: none; padding-bottom: 0; }

.plain-list strong { color: var(--text); }

/* Contact */
.contact-section { text-align: center; }

.contact-section p { color: var(--text-muted); max-width: 50ch; margin: 0 auto 28px; }

.contact-links { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }

/* Footer */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 28px 24px;
  text-align: center;
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* Responsive */
@media (max-width: 720px) {
  .nav-links {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--bg);
    border-bottom: 1px solid var(--border);
    flex-direction: column;
    padding: 16px 24px;
    gap: 16px;
    display: none;
  }

  .nav-links.open { display: flex; }

  .nav-toggle { display: flex; }

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

  .timeline li { grid-template-columns: 1fr; gap: 6px; }

  .pub-list li { grid-template-columns: 1fr; gap: 4px; }

  .hero { padding-top: 48px; }
}