:root {
  --paper: #f5f7fb;
  --paper-shade: #eaf1fb;
  --surface: #ffffff;
  --ink: #102033;
  --muted: #4a6280;
  --line: rgba(13, 27, 42, 0.12);
  --line-strong: rgba(13, 27, 42, 0.22);
  --slate: #102f4c;
  --slate-2: #1f5d93;
  --brick: #ef7f1a;
  --brick-2: #ffb35c;
  --moss: #259671;
  --shadow: 0 20px 44px rgba(16, 47, 76, 0.14);
  --shadow-soft: 0 10px 24px rgba(16, 47, 76, 0.09);
  --radius-md: 10px;
  --radius-lg: 14px;
  --container: min(1160px, calc(100% - 40px));
  --header-h: 84px;
  --serif: "IBM Plex Serif", Georgia, "Times New Roman", serif;
  --sans: "IBM Plex Sans", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "IBM Plex Mono", ui-monospace, "SFMono-Regular", Menlo, monospace;
}

html[data-theme="dark"] {
  --paper: #09111b;
  --paper-shade: #0f1a29;
  --surface: #122131;
  --ink: #ebf4ff;
  --muted: #a9bfd7;
  --line: rgba(171, 195, 220, 0.14);
  --line-strong: rgba(171, 195, 220, 0.26);
  --slate: #dcedff;
  --slate-2: #73b5ef;
  --brick: #f28d2e;
  --brick-2: #ffcf8e;
  --moss: #3fcf9e;
  --shadow: 0 22px 48px rgba(0, 0, 0, 0.4);
  --shadow-soft: 0 14px 28px rgba(0, 0, 0, 0.3);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--sans);
  background: var(--paper);
  color: var(--ink);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
img { max-width: 100%; display: block; }
a { color: inherit; text-decoration: none; }
button, input, textarea { font: inherit; }
h1, h2, h3 { font-family: var(--serif); font-weight: 600; letter-spacing: -0.01em; }
.container { width: var(--container); margin: 0 auto; }
.section { padding: 104px 0; position: relative; }
.section-alt { background: var(--paper-shade); }
.section-heading { max-width: 640px; margin-bottom: 44px; }
.section-heading h2 { font-size: clamp(1.7rem, 3.2vw, 2.5rem); line-height: 1.15; margin: 0; }
.eyebrow {
  display: flex;
  align-items: center;
  gap: 10px;
  text-transform: uppercase;
  letter-spacing: 0.14em;
  font-size: 0.72rem;
  color: var(--brick);
  font-weight: 600;
  font-family: var(--mono);
  margin: 0 0 14px;
}
.eyebrow::before {
  content: "";
  width: 22px;
  height: 1px;
  background: var(--brick);
  display: inline-block;
}
.section-note, .form-note { color: var(--muted); font-size: 0.95rem; }
.skip-link {
  position: absolute; left: -999px; top: auto; width: 1px; height: 1px; overflow: hidden;
}
.skip-link:focus {
  left: 16px; top: 16px; width: auto; height: auto; padding: 10px 14px;
  background: var(--surface); border-radius: 8px; z-index: 9999; border: 1px solid var(--line-strong);
}
.sr-only {
  position: absolute; width: 1px; height: 1px; padding: 0; margin: -1px;
  overflow: hidden; clip: rect(0,0,0,0); border: 0;
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(10px);
  background: color-mix(in srgb, var(--paper), transparent 12%);
  border-bottom: 1px solid var(--line);
}
.nav-wrap {
  min-height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}
.brand { display: flex; gap: 12px; align-items: center; }
.brand-mark {
  width: 42px;
  height: 42px;
  display: grid;
  place-items: center;
  border-radius: 8px;
  background: var(--slate);
  color: var(--paper);
  font-weight: 700;
  font-family: var(--serif);
  font-size: 0.95rem;
  letter-spacing: 0.02em;
}
.brand-text strong { display: block; font-size: 0.98rem; font-family: var(--serif); font-weight: 600; }
.brand-text small { color: var(--muted); font-family: var(--mono); font-size: 0.68rem; letter-spacing: 0.06em; text-transform: uppercase; }
.main-nav ul {
  display: flex; list-style: none; gap: 26px; padding: 0; margin: 0; align-items: center;
}
.main-nav a {
  position: relative;
  color: var(--muted);
  font-weight: 500;
  font-size: 0.88rem;
  letter-spacing: 0.01em;
}
.main-nav a::after {
  content: "";
  position: absolute; left: 0; bottom: -6px; width: 100%; height: 1px;
  transform: scaleX(0); transform-origin: left; transition: transform 0.2s ease;
  background: var(--brick);
}
.main-nav a:hover, .main-nav a:focus-visible { color: var(--ink); }
.main-nav a:hover::after, .main-nav a:focus-visible::after { transform: scaleX(1); }
.nav-toggle { display: none; }
.theme-toggle {
  width: 42px; height: 42px; border: 1px solid var(--line); border-radius: 8px;
  background: var(--surface); color: var(--ink); cursor: pointer;
}
.theme-toggle:hover { border-color: var(--line-strong); }

/* ---------- Hero ---------- */
.hero { padding: 64px 0 40px; overflow: hidden; }
.hero-grid { display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 56px; align-items: center; }
.hero-copy h1 {
  font-size: clamp(2.6rem, 6vw, 4.1rem);
  line-height: 1.04;
  margin: 0 0 18px;
}
.hero-copy h1 em { font-style: normal; color: var(--brick); }
.hero-text { max-width: 52ch; font-size: 1.08rem; color: var(--muted); margin: 0 0 32px; }
.hero-cta { display: flex; flex-wrap: wrap; gap: 14px; margin-bottom: 40px; }
.button {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 48px; padding: 0 24px; border-radius: 6px; border: 1px solid transparent;
  transition: transform 0.2s ease, background 0.2s ease, border-color 0.2s ease;
  font-weight: 600; font-size: 0.92rem;
}
.button:hover, .button:focus-visible { transform: translateY(-1px); }
.button.primary { background: var(--brick); color: #fff8f3; }
.button.primary:hover { background: var(--brick-2); }
.button.ghost { border-color: var(--line-strong); background: transparent; color: var(--ink); }
.button.ghost:hover { border-color: var(--slate); }
.hero-meta {
  list-style: none; padding: 20px 0 0; margin: 0; border-top: 1px solid var(--line);
  display: grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 20px;
}
.hero-meta li { padding: 0; }
.hero-meta strong {
  display: block; margin-bottom: 4px; font-family: var(--mono); font-size: 0.68rem;
  text-transform: uppercase; letter-spacing: 0.08em; color: var(--brick); font-weight: 600;
}
.hero-meta span { color: var(--ink); font-size: 0.95rem; font-weight: 500; }

/* Drawing panel */
.drawing-panel {
  position: relative;
  border-radius: 22px;
  overflow: hidden;
  background: linear-gradient(165deg, #123a5c 0%, #081726 100%);
  box-shadow: var(--shadow);
}
.drawing-panel::before {
  content: "";
  position: absolute; inset: 0;
  background-image: linear-gradient(rgba(255,255,255,0.07) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,0.07) 1px, transparent 1px);
  background-size: 26px 26px;
}
.drawing-panel::after {
  content: "";
  position: absolute; inset: 0;
  background: radial-gradient(circle at 85% 0%, rgba(255,179,92,0.16), transparent 45%);
}
.drawing-panel-inner { position: relative; z-index: 1; padding: 28px 28px 22px; }
.status-pill {
  align-self: flex-start; display: inline-flex; align-items: center; gap: 8px;
  padding: 7px 13px; border-radius: 999px; border: 1px solid rgba(255,255,255,0.18);
  background: rgba(255,255,255,0.07); color: #f2f7ff; font-size: 0.78rem; font-weight: 600; margin-bottom: 22px;
}
.status-pill::before { content: ""; width: 7px; height: 7px; border-radius: 50%; background: var(--moss); display: inline-block; }
.metric-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  margin-bottom: 26px;
}
.metric-grid article {
  padding: 14px 10px;
  border-radius: 10px;
  background: rgba(255,255,255,0.06);
  border: 1px solid rgba(255,255,255,0.14);
  text-align: center;
}
.metric-grid strong {
  display: block;
  font-family: var(--serif);
  font-size: 1.7rem;
  line-height: 1;
  margin-bottom: 6px;
  color: var(--brick-2);
}
.metric-grid span {
  font-size: 0.72rem;
  color: rgba(240,245,255,0.72);
  line-height: 1.3;
  display: block;
}
.diagram-svg { width: 100%; height: auto; display: block; }
.focus-chips { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 18px; }
.chip {
  font-size: 0.78rem; font-weight: 500; padding: 6px 12px; border-radius: 999px;
  border: 1px solid var(--line); color: var(--muted); font-family: var(--sans);
}

/* ---------- Generic cards ---------- */
.card, .cert-card, .timeline-card, .contact-form, .pub-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
}
.card { padding: 28px; }
.card h3 { font-size: 1.1rem; margin: 0 0 10px; }
.card p { color: var(--muted); margin: 0; font-size: 0.96rem; }

/* ---------- About ---------- */
.section-grid { display: grid; gap: 24px; }
.about-grid { grid-template-columns: 0.85fr 1.15fr; align-items: start; gap: 48px; }
.about-lead { font-family: var(--serif); font-size: 1.35rem; line-height: 1.45; margin: 0; }
.about-body p { color: var(--muted); font-size: 1rem; margin: 0 0 18px; }
.about-body p:last-child { margin-bottom: 0; }

/* ---------- Timeline ---------- */
.timeline { position: relative; margin-left: 4px; border-left: 1px solid var(--line-strong); }
.timeline-item { position: relative; display: grid; grid-template-columns: 128px 1fr; gap: 28px; padding: 0 0 36px 28px; }
.timeline-item:last-child { padding-bottom: 0; }
.timeline-item::before {
  content: ""; position: absolute; left: -5px; top: 4px; width: 9px; height: 9px;
  border-radius: 50%; background: var(--brick); border: 2px solid var(--paper-shade);
}
.timeline-year { color: var(--muted); font-family: var(--mono); font-size: 0.78rem; padding-top: 2px; letter-spacing: 0.02em; }
.timeline-card { padding: 20px 22px; }
.timeline-card h3 { font-size: 1.02rem; margin: 0 0 4px; }
.timeline-role { color: var(--brick); font-weight: 600; font-size: 0.85rem; margin: 0 0 8px; }
.timeline-card p:not(.timeline-role) { color: var(--muted); margin: 0; font-size: 0.94rem; }

/* ---------- Grids ---------- */
.edu-grid, .skills-grid, .cert-grid, .highlight-grid { display: grid; gap: 18px; }
.edu-grid { grid-template-columns: repeat(3, minmax(0,1fr)); }
.skills-grid { grid-template-columns: repeat(3, minmax(0,1fr)); }
.cert-grid { grid-template-columns: repeat(4, minmax(0,1fr)); }
.highlight-grid { grid-template-columns: repeat(3, minmax(0,1fr)); }
.tag {
  display: inline-flex; align-items: center; width: fit-content; padding: 5px 10px;
  border-radius: 4px; font-size: 0.72rem; font-weight: 600; font-family: var(--mono);
  letter-spacing: 0.03em; text-transform: uppercase;
  background: color-mix(in srgb, var(--slate), transparent 90%); color: var(--slate);
  margin-bottom: 12px;
}
.cert-card { padding: 20px; }
.cert-card .issuer { display: block; font-family: var(--mono); font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); margin-bottom: 10px; }
.cert-card h3 { font-size: 0.98rem; margin: 0 0 6px; font-family: var(--sans); font-weight: 600; }
.cert-card p { color: var(--muted); font-size: 0.85rem; margin: 0; }

/* ---------- Highlights (formerly projects) ---------- */
.header-with-tools { display: flex; justify-content: space-between; gap: 16px; align-items: end; flex-wrap: wrap; }
.filter-bar { display: flex; flex-wrap: wrap; gap: 8px; }
.filter-btn {
  min-height: 38px; padding: 0 14px; border-radius: 999px; background: transparent;
  border: 1px solid var(--line-strong); color: var(--muted); cursor: pointer; font-weight: 500; font-size: 0.84rem;
}
.filter-btn.active { background: var(--ink); border-color: var(--ink); color: var(--paper); }
html[data-theme="dark"] .filter-btn.active { background: var(--slate); border-color: var(--slate); color: var(--paper); }
.highlight-card { padding: 26px; display: flex; flex-direction: column; gap: 10px; }
.highlight-card h3 { font-size: 1.08rem; margin: 0; }
.highlight-card .highlight-meta { color: var(--muted); font-size: 0.82rem; font-family: var(--mono); margin: -4px 0 4px; }
.highlight-card p { color: var(--muted); margin: 0; font-size: 0.94rem; }

.orcid-chip {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  margin-top: 16px;
  padding: 7px 12px 7px 8px;
  border: 1px dashed var(--line-strong);
  border-radius: 999px;
  font-size: 0.8rem;
  color: var(--muted);
  font-family: var(--mono);
}
.orcid-chip:hover { border-color: var(--brick); color: var(--brick); }
.orcid-mark { width: 16px; height: 16px; flex-shrink: 0; }

/* ---------- Publications ---------- */
.pub-card { padding: 30px; display: grid; grid-template-columns: auto 1fr; gap: 26px; align-items: start; }
.pub-card + .pub-card { margin-top: 18px; }
.pub-icon {
  width: 46px; height: 46px; border-radius: 8px; background: color-mix(in srgb, var(--brick), transparent 90%);
  color: var(--brick); display: grid; place-items: center; font-family: var(--serif); font-weight: 600;
}
.pub-title { font-size: 1.15rem; margin: 0 0 8px; }
.pub-meta { color: var(--muted); font-size: 0.86rem; margin: 0 0 12px; }
.pub-desc { color: var(--muted); font-size: 0.96rem; margin: 0 0 14px; }
.pub-link { color: var(--brick); font-weight: 600; font-size: 0.88rem; border-bottom: 1px solid currentColor; padding-bottom: 1px; }

/* ---------- Leadership ---------- */
.split-grid { display: grid; gap: 20px; grid-template-columns: repeat(2, minmax(0,1fr)); }
.plain-list { margin: 0; padding-left: 0; list-style: none; display: grid; gap: 14px; }
.plain-list li { padding-left: 18px; position: relative; color: var(--muted); font-size: 0.95rem; }
.plain-list li::before { content: "—"; position: absolute; left: 0; color: var(--brick); }
.plain-list strong { color: var(--ink); }

/* ---------- Contact ---------- */
.contact-grid { display: grid; grid-template-columns: 0.85fr 1.15fr; gap: 40px; align-items: start; }
.contact-links { display: flex; gap: 14px; flex-wrap: wrap; margin-top: 24px; }
.contact-form { display: grid; gap: 16px; padding: 30px; }
.contact-form label { display: grid; gap: 8px; font-weight: 600; font-size: 0.88rem; }
.contact-form input, .contact-form textarea {
  width: 100%; border: 1px solid var(--line); background: var(--paper); color: var(--ink);
  border-radius: 6px; padding: 12px 14px; font-size: 0.95rem;
}
.contact-form input:focus, .contact-form textarea:focus { outline: none; border-color: var(--slate); }

/* ---------- Contact popup ---------- */
.form-error { color: var(--brick); font-size: 0.88rem; margin: 0; }
.popup-overlay {
  position: fixed; inset: 0; z-index: 100;
  display: flex; align-items: center; justify-content: center;
  background: color-mix(in srgb, var(--ink), transparent 45%);
  padding: 20px;
  opacity: 0;
  transition: opacity 0.2s ease;
}
.popup-overlay[hidden] { display: none; }
.popup-overlay.is-visible { opacity: 1; }
.popup-card {
  position: relative;
  width: min(400px, 100%);
  background: var(--surface);
  border: 1px solid var(--line-strong);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
  padding: 36px 32px 32px;
  text-align: center;
  transform: translateY(10px) scale(0.98);
  transition: transform 0.2s ease;
}
.popup-overlay.is-visible .popup-card { transform: translateY(0) scale(1); }
.popup-icon {
  display: inline-flex; align-items: center; justify-content: center;
  width: 44px; height: 44px; border-radius: 50%;
  background: color-mix(in srgb, var(--moss), transparent 84%);
  color: var(--moss); font-size: 1.2rem; margin-bottom: 16px;
}
.popup-card h3 { margin: 0 0 8px; font-size: 1.2rem; }
.popup-card p { margin: 0; color: var(--muted); font-size: 0.95rem; }
.popup-close {
  position: absolute; top: 12px; right: 12px;
  width: 30px; height: 30px; border-radius: 6px; border: none;
  background: transparent; color: var(--muted); font-size: 1.3rem; cursor: pointer;
  line-height: 1;
}
.popup-close:hover { background: var(--paper-shade); color: var(--ink); }

/* ---------- Footer ---------- */
.site-footer { padding: 40px 0 60px; border-top: 1px solid var(--line); }
.footer-grid { display: grid; grid-template-columns: 1.4fr 1fr 1fr; gap: 24px; align-items: start; }
.footer-brand { font-size: 1.1rem; font-weight: 600; font-family: var(--serif); margin-bottom: 10px; }
.footer-grid > div:first-child p { color: var(--muted); font-size: 0.9rem; max-width: 32ch; }
.footer-title { font-weight: 600; margin-bottom: 12px; font-family: var(--mono); font-size: 0.7rem; text-transform: uppercase; letter-spacing: 0.07em; color: var(--muted); }
.footer-links { list-style: none; padding: 0; margin: 0; color: var(--muted); display: grid; gap: 10px; font-size: 0.92rem; }
.footer-links a:hover { color: var(--brick); }
.back-to-top {
  position: fixed; right: 20px; bottom: 20px; width: 44px; height: 44px; border: 1px solid var(--line-strong);
  border-radius: 8px; background: var(--surface); color: var(--ink); font-size: 1.1rem; cursor: pointer;
  opacity: 0; pointer-events: none; transform: translateY(10px); transition: opacity 0.2s ease, transform 0.2s ease;
}
.back-to-top.visible { opacity: 1; pointer-events: auto; transform: translateY(0); }

/* ---------- Motion ---------- */
.reveal { opacity: 0; transform: translateY(16px); transition: opacity 0.5s ease, transform 0.5s ease; }
.reveal.is-visible { opacity: 1; transform: translateY(0); }
.hidden-card { display: none !important; }

/* ---------- Responsive ---------- */
@media (max-width: 1080px) {
  .hero-grid, .about-grid, .contact-grid, .split-grid, .footer-grid,
  .skills-grid, .highlight-grid, .edu-grid, .cert-grid {
    grid-template-columns: repeat(2, minmax(0,1fr));
  }
  .about-grid, .contact-grid, .footer-grid { grid-template-columns: 1fr; }
}

@media (max-width: 820px) {
  .section { padding: 76px 0; }
  .main-nav ul {
    position: absolute; top: calc(100% + 1px); right: 0; left: 0; min-width: unset;
    padding: 18px 20px; background: var(--paper); border-bottom: 1px solid var(--line);
    display: none; flex-direction: column; align-items: flex-start; gap: 16px;
  }
  .main-nav ul.is-open { display: flex; }
  .nav-toggle {
    display: inline-grid; gap: 4px; width: 42px; height: 42px; place-content: center;
    border-radius: 8px; border: 1px solid var(--line); background: var(--surface);
  }
  .nav-toggle span:not(.sr-only) { display: block; width: 18px; height: 1.5px; background: var(--ink); }
  .main-nav { display: flex; align-items: center; gap: 10px; position: relative; }
  .hero-grid, .skills-grid, .highlight-grid, .edu-grid, .cert-grid, .split-grid {
    grid-template-columns: 1fr;
  }
  .hero-meta { grid-template-columns: 1fr; gap: 14px; }
  .timeline-item { grid-template-columns: 1fr; gap: 8px; padding-left: 20px; }
  .pub-card { grid-template-columns: 1fr; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .reveal, .back-to-top, .button, .main-nav a::after { transition: none; }
}