:root {
  --bg: #0b1220;
  --bg-soft: #0f172a;
  --text: #e5e7eb;
  --muted: #94a3b8;
  --card: #0f172a;
  --border: #1f2937;
  --accent: #3b82f6;
  --accent-contrast: #ffffff;
}

html[data-theme="light"] {
  --bg: #f8fafc;
  --bg-soft: #ffffff;
  --text: #0f172a;
  --muted: #475569;
  --card: #ffffff;
  --border: #e2e8f0;
  --accent: #2563eb;
  --accent-contrast: #ffffff;
}

* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background: var(--bg);
  color: var(--text);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

.container { max-width: 1120px; margin: 0 auto; padding: 0 1rem; }

/* Accessibility */
.skip-link {
  position: absolute; left: -999px; top: -999px;
}
.skip-link:focus {
  left: 1rem; top: 1rem;
  background: var(--bg-soft); color: var(--text);
  padding: .5rem .75rem; border-radius: .5rem; outline: 2px solid var(--accent);
}

.h1 { font-size: clamp(2rem, 3vw + 1rem, 3.25rem); line-height: 1.1; margin: 0; }
.h2 { font-size: clamp(1.5rem, 1.6vw + 1rem, 2rem); margin: 0; }
.h3 { font-size: 1.125rem; margin: 0; }
.h4 { font-size: 1rem; margin: 0; }
.subhead { margin-top: .5rem; color: var(--muted); font-size: 1.125rem; }

/* Buttons */
.btn-primary, .btn-outline, .btn-ghost, .linklike {
  display: inline-flex; align-items: center; justify-content: center;
  gap: .5rem; border-radius: .75rem; text-decoration: none; cursor: pointer;
}
.btn-primary { background: var(--accent); color: var(--accent-contrast); padding: .6rem 1rem; font-weight: 600; }
.btn-primary:hover { filter: brightness(1.05); }
.btn-outline { border: 1px solid var(--border); color: var(--text); padding: .55rem .95rem; }
.btn-outline:hover { background: rgba(255,255,255,.03); }
.btn-ghost { border: 1px solid var(--border); background: transparent; color: var(--text); padding: .35rem .75rem; }
.linklike { border: none; background: none; color: var(--accent); text-decoration: underline; padding: 0; }

/* Header / Nav */
.site-header {
  position: sticky; top: 0; z-index: 50;
  backdrop-filter: blur(6px);
  background: color-mix(in srgb, var(--bg) 70%, transparent);
  border-bottom: 1px solid var(--border);
}
.nav { height: 56px; display:flex; align-items:center; justify-content:space-between; }
.brand { display:flex; align-items:center; gap:.5rem; }
.logo { width:32px; height:32px; border-radius:.75rem; background: linear-gradient(135deg, var(--accent), #22c55e); }
.brand-name { font-weight: 700; letter-spacing: .2px; }
.nav-links { list-style: none; display:flex; align-items:center; gap:1rem; margin:0; padding:0; }
.nav-toggle { display:none; border:1px solid var(--border); background:transparent; color:var(--text); padding:.35rem .5rem; border-radius:.5rem; }
@media (max-width: 720px) {
  .nav-toggle { display:block; }
  .nav-links { position:absolute; right:1rem; top:56px; background:var(--bg-soft); border:1px solid var(--border); border-radius:.75rem; padding:.5rem; width: 220px; flex-direction: column; align-items: stretch; }
  .nav-links[data-collapsed="true"] { display:none; }
}

/* Sections */
.section { padding: 3rem 0; }
.section-title { display:flex; flex-direction:column; gap:.25rem; }
.muted { color: var(--muted); }
.micro { font-size: .75rem; color: var(--muted); }

/* Hero */
.hero { padding-top: 2.5rem; }
.hero-grid { display:grid; grid-template-columns: 1.2fr .8fr; gap: 2rem; align-items: center; }
@media (max-width: 900px) { .hero-grid { grid-template-columns: 1fr; } }
.cta-row { display:flex; gap:.75rem; flex-wrap: wrap; margin-top: 1rem; }
.cred-list { display:grid; grid-template-columns: repeat(4, minmax(0,1fr)); gap:.5rem; margin-top:1rem; font-size:.85rem; color:var(--muted); }
.cred-list li { border:1px solid var(--border); padding:.5rem .75rem; border-radius:.5rem; text-align:center; }
.hero-photo img { width: 220px; height: 220px; object-fit: cover; border-radius: 1.25rem; border:1px solid var(--border); box-shadow: 0 10px 30px rgba(0,0,0,.35); }
@media (max-width: 900px) { .hero-photo { order:-1; display:flex; justify-content:center; } }

/* Cards */
.card-grid { display:grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: 1rem; margin-top: 1.25rem; }
@media (max-width: 960px) { .card-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 640px) { .card-grid { grid-template-columns: 1fr; } }
.card {
  background: var(--card); border:1px solid var(--border); border-radius: 1rem;
  padding: 1rem; box-shadow: 0 8px 24px rgba(0,0,0,.15);
}
.card-cta { color: var(--accent); text-decoration: underline; font-weight: 600; }

/* More projects */
.more-title { margin-top: 1.5rem; }
.more-grid { display:grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap: .75rem; }
@media (max-width: 800px) { .more-grid { grid-template-columns: 1fr; } }
.mini-card { border:1px solid var(--border); border-radius:.75rem; padding:.75rem; background: var(--bg-soft); }
.mini-title { font-weight: 600; }
.mini-desc { color: var(--muted); font-size:.9rem; }

/* Publications */
.pub-list { list-style:none; padding:0; margin: 1rem 0 0; display:grid; gap:.75rem; }
.pub-item { border:1px solid var(--border); border-radius: .75rem; padding: 1rem; background: var(--card); }
.pub-title { font-weight: 600; }
.pub-venue { font-size: .85rem; color: var(--muted); }
.pub-links a { color: var(--accent); text-decoration: underline; }

/* Education */
.edu-grid { display:grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top:1rem; }
@media (max-width: 800px) { .edu-grid { grid-template-columns: 1fr; } }
.edu-card { border:1px solid var(--border); border-radius:.75rem; padding:1rem; background: var(--card); }
.edu-school { font-weight: 600; }
.edu-degree, .edu-dates { color: var(--muted); font-size:.9rem; }

/* Gallery */
.gallery-grid { display:grid; grid-template-columns: repeat(3, minmax(0,1fr)); gap:.75rem; margin-top:1rem; }
@media (max-width: 900px) { .gallery-grid { grid-template-columns: 1fr 1fr; } }
@media (max-width: 520px) { .gallery-grid { grid-template-columns: 1fr; } }
.gallery-item img { width:100%; height:100%; object-fit: cover; border-radius:.75rem; border:1px solid var(--border); }

/* Contact */
.contact-grid { display:grid; grid-template-columns: 1fr 1fr; gap: 1rem; margin-top: 1rem; }
@media (max-width: 900px) { .contact-grid { grid-template-columns: 1fr; } }
.contact-card { border:1px solid var(--border); border-radius: .75rem; padding: 1rem; background: var(--card); }
.contact-row { display:flex; align-items:center; gap:.5rem; }
.contact-card input, .contact-card textarea {
  width: 100%; background: transparent; color: var(--text);
  border: 1px solid var(--border); border-radius: .5rem; padding: .6rem .75rem; margin-top: .5rem;
}
.contact-card input:focus, .contact-card textarea:focus { outline: 2px solid var(--accent); outline-offset: 2px; }
.hp { display:none; }

/* Footer */
.site-footer { border-top:1px solid var(--border); padding: 2rem 0; }
.footer-grid { display:flex; align-items:flex-start; justify-content:space-between; gap:1rem; }
.footer-links { display:flex; gap:1rem; }
.footer-links a { color: var(--muted); }
.footer-links a:hover { color: var(--text); }